Physiological Based Simulation of the Immune System

This is an old Physiological simulation of the Immune System, simulating the influenza virus done around 1999 to 2001.

Disclaimer: This article has not been peer reviewed or published. Provided for informational purposes only.

Contents

Source Code

  • Psim_immune.cpp .cpp file (Physiological simulation of the Immune System source code)
  • Psim_immune.h .h file (Physiological simulation of the Immune System source code)

Introduction

This is an old Physiological simulation of the Immune System, simulating the influenza virus done around 1999 to 2001. The model is based on a bronchial tissue model by Bocharov1994 and a immunological model based on the localization-dose-time model of Zinkernagel2000:

Physiological System and Compartments

Schematic of Cardiovascular Compartments

          82.5mm3/msec        pulmonaryCapillary     82.5mm3/msec (ml/sec)
  |------------>------------O--------+-----------O-------->--------------------|
  | VenaCava                      ___|___                                 aorta|
  |                              |       |      _______                        |
  |                              | lungs |     |       |                       |
  |                              |_______|     | brain |                       |
  |                                            |_______|                       |
  |       12.49mm3/msec                            |               12.5mm3/msec|
  |------------<------------------------O------------------------O------<------|
  |                                     |     |   cerebralCapillary            |
  |                  _________          |   __|_________                       |
  |                 |         |         |  |            |                      |
  |                 |pituitary|         |<-|hypothalamus|                      |
  |                 |_________|         |  |____________|                      |
  |   0.01mm3/msec      |               |                                      |
  |-------<----O------------------O------                                      |
  |              hypophysealPortal                                             |
  |                                                                            |
  |                                                 4.2mm3/msec                |
  |                              |----<------------------<---------------------|
  |               _______        |                 ____________                |
  |              |       |       |                |            |               |
  |              | liver |       |                |stomach, si |               |
  |              |_______|       |                |____________|               |
  |  21.7mm3/msec    |           |                      |        15.0mm3/msec  |
  |------<----O------------------O----<------O------------------O-----<--------|
  |             hepaticSinusoid  |                 portalVein                  |
  |                              |                   _______                   |
  |                              |                  |       |                  |
  |                              |                  | spleen|                  |
  |               _______        |                  |_______|                  |
  |              |       |       |                      |        2.5mm3/msec   |
  |              |kidneys|       |----<------O------------------O-----<--------|
  |              |_______|                    splenicCapillary                 |
  |  20.0mm3/msec    |                                                         |
  |------<----O------------------O------------------------------------<--------|
  |            GlomularCapillary                                               |
  |                _______      _______      _______     _______               |
  |               |       |    |adipose|    | bone  |   |other  |              |
  |               |muscle |    |tissue |    |marrow |   |tissue |              |
  |               |_______|    |_______|    |_______|   |_______|              |
  |  28.3mm3/msec     |            |            |           |                  |
  |------<----O---------------------------------------------------O---<--------|
                        genericCapillary

Notes:

  1. miscellaneous:
    1. see vessel compartment values table for more information

Schematic of Lymphatic Compartments

Lymph                                ____________                          Blood
      125.0ml/hr -->                |  Lymph     |
|---------------------------------->|  Junction  |---------------------------->|
|  ThoracicDuct(2,3,4,5)            |____________|          VenaCava           |
|  1.25e9cells/hr, 3.0e10cells/day                                             |
|                                                                              |
|ThoracicDuct1       ____________                                              |
|                   |            |<--------------------------------------------|
|                   |  Hepatic   |                             ______          |
|                   | Lymph Nodes|   14ml/hr                  |      |         |
|<------------------|            |<---------------------------|Liver |<--------|
|  14.0ml/hr        |  77grams   |   HepaticAfferent          |      |         |
|  (1.4e8cells/hr)  |____________|   1.4e7cells/hr            |______|         |
|                    ____________                                              |
|                   |            |<--------------------------------------------|
|                   |Subcutaneous|                             ______          |
|                   | Lymph Nodes|    1.3ml/hr                |      |         |
|<------------------|            |<---------------------------| Skin |<--------|
|   1.3ml/hr        |   7grams   |    SubcutaneousAfferent    |      |         |
|  (1.3e7cells/hr)  |____________|    1.3e6cells/hr           |______|         |
|                    ____________                                              |
|                   |            |<--------------------------------------------|
|                   |   Misc.    |                             ______          |
|                   | Lymph Nodes|    31.0ml/hr               |      |         |
|<------------------|            |<---------------------------| Misc |<--------|
|  31.0ml/hr        |  175grams  |     miscAfferent           |Tissue|         |
|  (3.1e8cells/hr)  |____________|    3.1e7cells/hr           |______|         |
|                                                         muscle/kidney/etc    |
|                                 +--------------------------------------------|
|                  ___________    |                            ______          |
|                 |           |   |                           | nalt |         |
|                 |           |<--+                           |......|         |
|                 |Mediastinal|                               | lalt |         |
|                 |  Lymph    |      30.0ml/hr                |......|         |
|<----------------|  Nodes    |<------------------------------|(balt)|<--------|
|  30.0ml/hr      |           |  Mediastinal Afferent         |      |         |
| (3.0e8cells/hr) |           |    3.0e7cells/hr              |......|         |
|                 | 168grams  |                               |lungs |         |
|                 |___________|                               |______|         |
|                                                             respiratory      |
|                                                              tract           |
|                  ___________                                                 |
|                 |   Test    |<-----------------------------------------------|
|                 |Mediastinal|                                _______         |
|                 |Lymph Node |     2.1 ml/hr                 | Test  |        |
|<----------------|           |<------------------------------|Bronchi|<-------|
|  2.1 ml/hr      |  12 grams |  Test Mediastinal Afferent    |_______|        |
|                 |___________|                                                |
|                                                                              |
|                                                                              |
|                                +-------------------------------+-------------|
|                  __________    |                 __________    |    ______   |
|                 |          |   |                |          |<--|   |      |  |
|                 |          |<--+                |  Peyers  |   |   |      |  |
|                 |Mesenteric|               |<---|  Patch   |<----->|      |  |
|                 |  Lymph   |   49.0ml/hr   |    |__________|   |   |      |  |
|<----------------|  Nodes   |<--------------|     __________    |   |      |  |
   49.0ml/hr      |          |   Mesenteric  |    |          |<--+   |      |  |
  (4.9e8cells/hr) |          |   Afferent    |    | Lamina   |       |      |  |
                  | 273grams | 4.9e7cells/hr |<---| Propria  |<----->|      |  |
                  |__________|                    |__________|       |______|  |
                                                                    intestine  |
                                                                               |
                   +------------------------+-------------------------+--------|
                   |      est:2.6e9cells/day|          2.5e11cells/day|        |
   ____________    |        ____________    |         ____________    |        |
  |            |<--+       |            |<--+        |            |<--+        |
  |   Thymus   |           |   Bone     |            |   Spleen   |            |
  |            |           |   Marrow   |            |            |            |
  |____________|-->|       |____________|-->|        |____________|-->|        |
                   |                        |                         |        |
    ~2.9e9cells/day|        ~3.0e10cells/day|                         |        |
                   +------------------------+-------------------------+--------|

Notes:

  1. miscellaneous:
    1. see vessel compartment values table for more information
    2. References: Zhu1996, Pabst1988, Young1994, Springer1994
    3. CellFlowPerHour = flow * EfferentConcentration
    4. thoraticDuctFlow: 125ml/hour = 2-3liters/day = 0.0347mm3/msec = 4.167e4 mm3/20 minutes, Guyton P.194;
    5. thoraticDuctCellsPerHour = ~0.3e11 cells/day = 1.25e9cells/hour; Pabst1988
  2. Total exchange from blood is 5.0e11/day, Pabst1988
  3. Pabst1988: Spleen, Lymph junction flows
  4. most flow numbers from Zhu1996
  5. Liver, Small intestine flow cross checked with Young1994
  6. lymphNode weights proportional to flows. (test mediastinal lymphNode from Bocharov1994)

Lymph Node Flow diagram

Adapted from Young1999, Seabrook1999. 1 gram lymph node receives
0.012% of cardiac output = ~1.2e8 cells/hour (at least 1 in 4 lymphocytes
cross the HEV and enter the lymph node). average transit time
(blood -> efferent) = ~20 hours for lymphNode (6 hrs for spleen), minimum
appearance time = 1-2hours. Total lymph nodes receives 1-2% of cardiac output.

                              _________
                          HEV|         |
Blood ---------------------->| lymph   |
 flow  = 26e6 cells/hr       | node    |
 (naive > memory)            |         |-----------> Efferent Lymph
                             | 1 gram  |     flow  = 30e6 cells/hr (1gram node)
                             |         |
Afferent Lymph ------------->|         |          100% lymphocytes
 flow  = 3e6 cells/hr        |_________|            5% produced within node
 (memory > naive)         (1gram = 2e9 cells)      10% from afferent
                                                   85% from blood (HEV)
6-12 afferent/Node
each at 1e6 cells/hour
10-15% macrophage/dendritic, 5-15% dendritic (Fossum1989)
85-90% lymphocytes

Immune System

Overview

The immunological architecture for this design is based on the localization-dose-time model
of Zinkernagel2000:

Briefly stated, the localization-dose-time model proposes that antigen structure, dose, time and the localization of antigen — vis-a-vis the organized lymphoid tissues — determines reactivity as follows:

  • Antigen that does not reach secondary lymphoid organs in minimum doses or for sufficiently long time periods is immunologically ignored.
  • Antigen that either usually exists in the lymphoid systems or reaches it and persists in excessive amounts for long periods deletes T cells (clonal exhaustion).
  • Antigen that is transported to secondary lymphoid organs in sufficient (but not excessive) amounts and for a sufficient time period (but does not persist) induces an effective immune response.

Kinetic data to develop this model is provided by Gudmundsdottir1999 and Iezzi1998 for tCell activation vs. time and antigen dose.
B cell peripheral tolerance is based on the Fulcher1996 article: localization, dosage and lack of tCell help.

This design also builds upon previous mathematical models, in particular: Bocharov1994, for the influenza A bronchial tissue model. And Kesmir1999 for Germinal center kinetic data.

Some Mathematical Modeling References

  • Kesmir1999, germinal center kinetics
  • Funk1998, Viral immune response
  • Rundell1998, Influenza B, primary/secondary response
  • Bocharov1994, Influenza A
  • Marchuk1991, Hepatitis B, lymphNode data

Some Useful Immunological Reviews

  • General Architecture:
    • Zinkernagel2000: localization-dose-time model
    • Doherty1995: Anatomical environment in immunity. Cognate, milieu, bystander effects
    • Matzinger1994: Two-signal “danger” model
  • tCell References:
    • Doherty2000: virus specific tCell response
    • Swain1996: tCell overview
  • bCell References:
    • Maclennan1997: germinal center
    • Maclennan1993: bCell overview
    • Liu1991: germinal center
  • Peripheral Tolerance References:
    • Fulcher1996: bCell tolerance: function of system (dosage, lack of tCell help)
    • Goodnow1995: alternative bCell tolerance model: follicular exclusion
    • Oral Tolerance:
      • Weiner1994: review
      • Faria1999: review
      • Chung1999: Memory cells refactory to oral tolerance
    • Also see: Zinkernagel2000, Matzinger1994 for tCell tolerance

Primary Humoral Immune Response Schematic (influenza):

                                 plasmaCell
          ...........................||.............................
          .INFECTED TISSUE           ||                            .
          .                          /          antigen           .
          .    infectedCell         igA            ||              .
          .        ||                              []<==igA        .
          .        ||Replication                   ||neutralization.
          .        /                              /              .
          .      antigen                           Die             .
          .                                                        .
          .       dendriticImmature              macrophage        .
          .               ||                        ||             .
          .               []<== antigen             []<== antigen  .
          .               ||                        ||             .
          .               /                        /             .
          .         dendriticApc                macrophageApc      .
          .               ||                        ||             .
          ................||........................||..............
                          ||                        ||
..........................||........................||........................
.                         /                        /                       .
.       thNaive                   bCellNaive                 macrophageApc   .
.         ||                        ||                           ||          .
.         []<==dendriticApc         []<==dendriticApc            ||die       .
.         ||                        ||   (or antigen)            /          .
.         /                        /                         antigen       .
.       thBlast                   bCellApc                       ||          .
.         ||                        ||                           []<==igM    .
.         []<== il2                 []<== thEffector             ||          .
.         ||replicate               ||activate                   /          .
.         ||                        ||                       immuneComplex   .
.         []<==dendriticApc         /                                       .
.         ||polarize               bCellBlast                                .
.         /                        ||    ||                                 .
.     thEffector        ClassSwitch ||    ||                                 .
.         ||           thEffector==>[]    /                                 .
.         ||          dendriticApc  ||   bCellPlasmaMedullary==> igM         .
.         ||  tZone                 ||                                       .
.   ----  ||  -------------------   ||  -------------------------------      .
.         ||                        ||                       follicle        .
.         ||               replicate[]                                       .
.         /                        ||                                       .
.     thGerminalCenter              /                                       .
.                             bCellCentroblast==> die                        .
.                                   ||                        dark zone      .
.                 ---------------   []duplicate   ---------------------      .
.                                   ||                       light zone      .
.                                   /                                       .
.                fdcapc      bCellCentrocyteInitial==> die                   .
.                 / ||             ||                                       .
. immuneComplex==>[] []==>Antigen==>[]                                       .
.                 || ||             ||                                       .
.                 || /             /                                       .
.                  fdc          bCellCentrocyteApc==> die                    .
.                                   ||                                       .
.                thGerminalCenter==>[]                                       .
.                                   ||                                       .
.                                   /                                       .
.LYMPH NODE                       bCellCentrocyte==> bCellCentroblast        .
.or SPLEEN                         ||       ||       (re-entry)              .
...................................||.......||................................
                                   /       /
                             plasmaCell    bCellMemory

Immune System Models:

LymphNode/Spleen Common model

Equations common to both lymph node and spleen

TcCell (CD8) (T Zone (pals))

Migration, TcNaiveBlood => TcNaive:

rate = k2 * TcNaiveBlood;
TcNaive += rate;
TcNaiveBlood -= rate; 

k2 Based on flow rate of 0.21 ul/sec-gram (or 1151 ul/sec for spleen, Pabst1988), from rate of thymus generation, tCell half life, size of tCell pool in lymphNode.

TcNaive => die:

rate = k2 * TcNaive;
TcNaive -= rate;

k2 from: HL = ~27weeks, derived from Berzins1998

Activation (with anergy), TcNaive + professionalAPC => TcBlast:

Based on Zinkernagel2000 localization/time/dosage model:

TcNaive (CD8) Activation Table
Apc type Apc concentration Notes
Low Medium High
Dendritic (with influenza virus) 1k/ml 10k/ml 100k/ml adapted from Ludewig1998
Dendritic (with rye grass) 1k/ml 10k/ml 100k/ml adapted from Ludewig1998
bCellMemoryApc (with influenza virus) 10k/ml 100k/ml 1000k/ml HamiltonEaston1995 (scaled by Ludewig1998)

also see: Iezzi1998 fig.1

Computer model uses 4 intermediate “activation” states between TcNaive and TcBlast: TcBlastPrecursor1,2,3,4 and also a TcAnergy state

step 1: TcNaive + professionalAPC => TcBlastPrecursor1:

rate = k2 * dendriticApc * tcNaive / (km + dendriticApc);
tcBlastPrecursor1 += rate;
tcNaive -= rate; 

tcNaivehalflife: 3 hours @ high dosage, 10 hours @ low dosage,
and > 98% activated in 20 hours from Gudmundsdottir1999 to match corresponding responder frequency, see step 2

step 2: TcBlastPrecursor1,2,3,4 + professionalAPC => TcBlastPrecursor2,3,4,TcBlast (tcAnergy):

Activation time: Iezzi1998: 10 hours @ high dosage, 30 hours @ Low dosage

Anergy: Gudmundsdottir1999: As the tCell proceeds from TcBlastPrecursor1 to TcBlast, a percentage of tCells will go to the anergy state depending on dosage: 23% anergy (77% responder frequency) @ high dosage, 80% anergy (20% responder frequency) @ Low dosage

repeat every 3 hours {
 rate = k2 * dendriticApc * tcBlastPrecursor4 / (km + dendriticApc);
 tcBlast += rate;
 tcAnergy = tcBlastPrecursor4 - rate;
 tcBlastPrecursor4 = 0;
 rate = k2 * dendriticApc * tcBlastPrecursor3 / (km + dendriticApc);
 tcBlastPrecursor4 += rate;
 tcAnergy = tcBlastPrecursor3 - rate;
 tcBlastPrecursor3 = 0;
 rate = k2 * dendriticApc * tcBlastPrecursor2 / (km + dendriticApc);
 tcBlastPrecursor3 += rate;
 tcAnergy = tcBlastPrecursor2 - rate;
 tcBlastPrecursor2 = 0;
 rate = k2 * dendriticApc * tcBlastPrecursor1 / (km + dendriticApc);
 tcBlastPrecursor2 += rate;
 tcAnergy = tcBlastPrecursor1 - rate;
 tcBlastPrecursor1 = 0;
} 

Rate = .94 @ high dosage (anergy = 23%), .65 @ low dosage (anergy = 80%)

minimum appearance time (from tcNaive to tcBlast) = 12 hours, average time: 12.8 hours @ rate = .94, 18.5 hours @ rate = .65

TcBlastPrecursor2,3,4,TcBlast => il2:

rate = k2 * TcBlastPrecursor[4,3,2],TcBlast;
il2 += rate; 

from Cho1999 (fig.2) after 24 hours il2 = ~15ng/ml @ 5.0e5 cells (also see: Zimmermann1999, Hamann1997, Gett1998)
~300 molecules/second; conversion factor: il2: 1ng = 6.5e-8 umoles, 10 units = 1ng

Clonal Expansion, TcBlast + il2 => TcEffector:

  • MuraliKrishna1998: (fig.4) 1 tCell increases to ~1.0e5 in ~7days = ~17 repetitions = ~10 hours/rep. (maximum rate = 6-8hours, slowing to 24-30hours as antigen clears);
  • MuraliKrishna1998: (fig.4) ~11 replications in 5 days (days 3-8): from day 3 to 5: ~9 replications @ 6-8hours/rep; from day 5 to 8: ~2-3 replications @ 24-30hours/rep; estimate: from day 1 to 3: ~6 replications @ 8hours/rep;
  • Gudmundsdottir1999: 7+ repetitions from Blast to Effector, repetition speed is antigen dependent;
  • Oehen1998: average 8 hours per repetition;
  • Swain1999 (cd4), antigen not needed (revisit this for homeostasis, especially secondary response, ditto th expansion);
  • Hamann1997: il2 (or il15 or il4) required for replication;
  • Bocharov1994: tcEffector increase = ~10k in 3 days, ~14 repetitions, 1rep each ~five hours,

Computer model uses 15 intermediate states between TcBlast and TcEffector: TcEffectorPrecursor1 to TcEffectorPrecursor15, each state represents 1 replication (also assumes replication rate is dependent on il2, not antigen)

TcBlast,TcEffectorPrecursor[1..15] + il2 => TcEffectorPrecursor[1..15],tcEffector

rateReplication = k2 * il2 / (km + il2);
count += rateReplication;
if(count >= 1.0){
  count = 0;
  rate = kDispersion * TcEffectorPrecursor15;
  tcEffector += 2 * rate;
  TcEffectorPrecursor15 -= rate;
  rate = kDispersion * TcEffectorPrecursor[14..1];
  TcEffectorPrecursor[15..2] += 2 * rate;
  TcEffectorPrecursor[14..1] -= rate;
  rate = kDispersion * TcBlast;
  TcEffectorPrecursor1 += 2 * rate;
  TcBlast -= rate;
} 

rateReplication (k2,km):

  • Cho1999, Gett1998: il2 vs. time/replications
  • constraint: averageReplicationTime = 50 hours @ il2 = 0.03 ng/ml
  • constraint: averageReplicationTime = 15 hours @ il2 = 0.3 ng/ml
  • constraint: averageReplicationTime = 7.5 hours @ il2 = 10.0 ng/ml
  • fit k2,km to these constraints (note: multiply by kDispersion to get minimumReplicationTime)

Dispersion (dispersion coefficient):

  • MuraliKrishna1998: minimum appearance time is ~72 hours. If assume 16 replications then minimumReplicationTime = 4.5 hours; averageReplicationTime (days 1-5) is ~6-8hours
  • kDispersion = minimumReplicationTime / averageReplicationTime = ~4.5/7.5 = 0.6
  • derived from: averageReplicationTime = kDispersion * minimumReplicationTime * (1 + 2k + 3k^2 + 4k^3…) = kDispersion * minimumReplicationTime / ((1-k)^2) = kDispersion * minimumReplicationTime / kDispersion^2; (note: k = 1 – kDispersion)
  • but see: Hasbold1998: bCell cycle times are all at the same rate, therefore kDispersion = 1.0

TcEffectorPrecursor1,2,3…15 => il2:

totalPrecursor = TcEffectorPrecursor[10..1]
rate = k2 * totalPrecursor;
il2 += rate; 

Cho1999, Gett1998: il2 vs. time/replications

uses same k2 as: TcBlastPrecursor2,3,4,TcBlast => il2
tcEffector Produces minimal il2, Hamann1997, assume cutoff at TcEffectorPrecursor10

il2 + TcEffectorPrecursor1,2,3…15 => autocrine usage:

rate = k2 * il2 * totalPrecursor;
il2 -= rate; 

uses same totalPrecursor as: TcEffectorPrecursor1,2,3…15 => il2

k2 from: tHalflife = 45 hours @ totalPrecursor = 2.0e7/ml

Assume kinetics similar to ifnAlpha, then from Bocharov1994 each tCell consumes ~50 il2 molecules/min = 1.4e-18 umoles/sec-cell, il2 concentration = 6.5e-6 umoles/ml (~100ng/ml)

TcEffector + il2 => 2TcEffector:
ignore for now, ~10x slower than TcBlast, Hamann1997

Activation, TcMemory + professionalAPC => TcMemoryBlast:

rate = k2 * dendriticApc * tcMemory / (km + dendriticApc);
tcMemoryBlast += rate;
tcMemory -= rate; 

activation time = 6 hours, Lalvani1997
1 hour to activate, Iezzi1998, activates even at low doses
Estimate about 10x primary Curtsinger1998, (Zimmermann1999: memory similar to naive)

TcMemoryBlast => il2:
Similar to naive blast, Hamann1997, table 3 (higher amounts, Zimmermann1999)

Clonal Expansion, TcMemoryBlast + il2 => TcEffector:
MuraliKrishna1998: re-challenge (fig.6b): 1 tCell increases to ~110-300 in ~5days = ~7-9 repetitions (day0-3: 5-6 divisions, day4-5: 2 divisions)
Zimmermann1999 20-50% lower than naive tCells, become effectors more quickly
Flynn1999: 5-10x greater than naive.
Cho1999: requires il15. Kedl1998: effectors within twelve hours. (Homeostatis, “decreasing potential hypothesis”)

TcMemory => die:

long lived?

ThCell (CD4) (T Zone (pals))

Migration, ThNaiveBlood => ThNaive:

ThNaive recirculate blood->lymph organs (high endothelial venules, HEV), Swain1999. Rose p.30: naive tCells usually don’t enter non-lymphoid tissue; CCR7, L-selectin, home to lymph, Lanzavecchia 2000

rate = k2 * ThNaiveBlood;
ThNaive += rate;
ThNaiveBlood -= rate; 

k2 Based on flow rate of 0.35 ul/sec-gram (or 1151 ul/sec for spleen, Pabst1988), from rate of thymus generation, tCell half life, size of tCell pool in lymphNode.

ThNaive => die:

rate = k2 * ThNaive;
ThNaive -= rate;

k2 from: HL = ~7weeks, Swain1996, Berzins1998
However, seems to be homeostasis regulated. Sprent1994: tHalfLife = years, if thymus is removed (same for tcNaive)

Activation (with anergy), ThNaive + professionalAPC => ThBlast:

See TcNaive activation (step1: tHalfLife = 3 hours @ high, 10 hours @ low; step2: rate = .94 @ high, .65 @ low)
Based on Zinkernagel2000 localization/time/dosage model
This equation is broken into 2 steps, step 1 is the initial activation from ThNaive to thBlastPrecursor1, and step 2 from tcBlastPrecursor1 to tcBlast, adapted largely from the Gudmundsdottir1999 article.

ThBlastPrecursor3,4,ThBlast => il2:

rate = k2 * ThBlastPrecursor[4,3],ThBlast;
il2 += rate; 

from Cho1999 (also see: Zimmermann1999, Hamann1997, Gett1998), ~300 molecules/second

Clonal Expansion, ThBlast + il2 => ThEffector:

Assume similar to TcNaive clonal expansion
Overall magnitude and duration at least 3 to 4 fold less than cd8, Doherty2000 p.582
Swain1996: 10reps @10 hours/rep, 4-5 days
Swain1999: antigen not needed, divisions: ~6-8 hours;

Polarization: ThEffectorPrecursor + dendriticApc => ThEffectorPrecursor:

This hypothetical model is based on dendritic cells carrying a “third signal” (derived from the anatomical environment of the tissue of origin) which regulates the th1/th2 cytokine profile. See:

  • Kalinski1999, third signal model
  • Iwasaki1999
  • Secrist1995, ApcType
  • MaldonadoLopez1999
  • Stumbles1998
  • Sangster1997, cytokine profiles
  • Everson1996
  • Doherty1995, anatomical environment
  • Mo1995
  • Sarawar1994

The model assumes cognate interactions between thCell and dendritic cell determine polarization (instead of milieu cytokine interactions), from Sangster1997
And from Marshall1999: “Th cells may be imagined as decoding information from DC as to the nature of the antigen they carry and the site of entry, and flexibly “interpreting” this information for antigen-specific B cells in their immediate vicinity.”

Results from influenza studies: Sangster1997, Sarawar1994, Doherty1995 Secrist1995 and Marshall1999 were used to develop and constrain the tCell polarization algorithm as well as the bCell class switching algorithm.

  • Influenza cytokine profile: Minimal il4, il5, tnfAlpha. Il2, ifnGamma increase from day 3 through day 7. Il10 remains constant from day 3 through 7. Sarawar1994, Mo1995
  • Assume dendritic cells are producing il10 and il12 (il12 polarizes th cells to th1-like cytokine profile: il2, ifnGamma). Sarawar1994, Mo1995
  • Initial site anatomy dependent: Same virus injected in 2 different locations generates in one case an igA response and in the other an igG response, Sangster1997
  • cognate not milieu or bystander effects: 2 different virus responses in same lymphNode at same time, one is igA, the other is igG, Sangster1997
  • lymphNode environment independent: virus specific APC are igA, others are igG, Sangster1997
  • igA class switching: il4 or il6 not required, Sangster1997
  • class switching possibly dependent on APC and dose (Allergen immunotherapy) Secrist1995
  • tMemory => bCellNaive => ig profile, reflects current infection, not the tMemory (old) infection, (re-polarization) Marshall1999
ThCell Polarization Table
Dendritic
il12
thCell Polarization (in %) Notes
th0 th1 th2
100% 17 83 0 strong th1
Iezzi1999
0% 59 1 40 strong th2
Iezzi1999
Polarization algorithm:
 for all ThEffectorPrecursor {
  il12 = dendriticApc.profile[IL12] ;
  rate = k2th1 * ThEffectorPrecursor.profile[TH0] * il12 / (kmth1 + il12) ;
  ThEffectorPrecursor.profile[TH0] -= rate ;
  ThEffectorPrecursor.profile[TH1] += rate ;
  x1 = 1.0 - il12;
  rate = k2th2 * ThEffectorPrecursor.profile[TH0] * x1/ (kmth2 + x1) ;
  ThEffectorPrecursor.profile[TH0] -= rate ;
  ThEffectorPrecursor.profile[TH2] += rate ;
 } 

Set k2th1,kmth1, etc. such that at the end of 10 repetitions, th cell profile percentages match table values.

ThEffector => il2:

th2 generates no il2; estimate th0, th1 generate at ~300 molecules/sec.

il2 + ThEffectorPrecursor => autocrine usage:

See TcEffectorPrecursor autocrine usage

ThEffector => thGerminalCenter:

rate = k2 * ThEffector;
if (thGerminalCenter > thGerminalCenterTarget) {
  rate = 0; /* LIMIT FUNCTION */
}
ThEffector -= rate;
thGerminalCenter += rate; 

Assume number of thGerminalCenter cells are anatomically constrained to 5-10% of total germinal center cells, Gray1997
Set thGerminalCenterTarget = maximumThGerminalCenter * numberOfGerminalCenters; maximumThGerminalCenter = ~1500 cells/GC
maximum death rate = 0.036 cells/sec, therefore set tHalfLife = ~2 hours

thGerminalCenter => die:

tHalfLife = 8 hours, Kesmir1999

Replication: thGerminalCenter => 2 thGerminalCenter:

GulbransonJudge1997 (nothing for now)

Activation, ThMemory + professionalAPC => ThMemoryBlast:

rate = k2 * dendriticApc * thMemory / (km + dendriticApc);
thMemoryBlast += rate;
thMemory -= rate; 

Assume same as tcMemory

dendritic cell needed for secondary response, Lambrecht1998, Lambrecht2001

ThMemoryBlast => il2:

assume same as naive blast

Clonal Expansion, ThMemoryBlast + il2 => ThEffector:

Assume same as tcMemory

ThMemoryBlast + dendriticApc => ThMemoryBlast re-Polarization:

See Marshall1999 (placeHolder for now), also Kalinski2000 p.1877

ThMemory => die:

long lived?

bCell (T-Zone, Follicles)

Migration, bCellNaiveBlood => bCellNaive:

rate = k2 * bCellNaiveBlood;
bCellNaive += rate;
bCellNaiveBlood -= rate; 

k2 Based on flow rate of 1.15 ul/sec-gram (or 1151 ul/sec for spleen, Pabst1988), from rate of boneMarrow generation, bCell half life, size of bCell pool in lymphNode.

Migration, bCellNaiveRecirculatingBlood => bCellNaiveRecirculating:

migrates: blood -> tzone -> follicules -> lymph -> blood

rate = k2 * bCellNaiveRecirculatingBlood;
bCellNaiveRecirculating += rate;
bCellNaiveRecirculatingBlood -= rate; 

k2 Based on flow rate of 0.24 ul/sec-gram (or 1151 ul/sec for spleen, Pabst1988), from afferent and efferent flow rates, 125ml/hr, 1.25e9 cells/hr = 347222 cells/sec = 34722 bCells/sec = 50bCells/sec-gram.

bCellNaive => (die):

apoptosis ,HL = 3 days, Janeway P.215, Liu1997; MacLennan1997: > 90% die. Also can derive from size of bCellNaive pool, boneMarrow generation and bCellNaiveRecirculating half life.

bCellNaive => bCellNaiveRecirculating:

rate = k2 * bCellNaive / (ki + bCellNaiveRecirculating);
bCellNaiveRecirculating += rate;
bCellNaive -= rate; 

homeostasis equation from MacLennan1997 page 58 item ii
Also see follicular exclusion, Liu1997, Goodnow1995 (peripheral tolerance for auto reactive bCells)

bCellNaiveRecirculating => (die):

rate = k2 * bCellNaive * bCellNaiveRecirculating;
bCellNaiveRecirculating -= rate; 

homeostasis equation from MacLennan1997: HL (follicles) = 4-5 weeks (page 58, items i, iii)

bCellNaiveRecirculating + dendriticApc => bCellAPC:

rate = k2 * bCellNaiveRecirculating * dendriticApc / (km + dendriticApc);
bCellNaiveRecirculating -= rate;
bCellAPC += rate; 

k2,km from: MacPherson2000: DC/bCell clusters, tHalfLife = ~6 hours at dendriticApc sufficient (1k/ml low-level)
currently antigen is from dendritic cells. from Wykes1998, MacPherson2000. Revisit for free antigen, MacLennan1997

Peripheral Tolerance: bCellAPC => (die):

tHalfLife = 3 days, MacLennan1997 page 58

MacLennan1997: stays in Tcell zone and no longer recirculates, waits for t-cell or dies
Peripheral Tolerance Model from Fulcher1996: bCell tolerance is function of system (dosage and lack of tCell help). Autoreactive cells (lacking tCell help) die here.
(but see: T independent response model — Baumgarth2000)

Activation: bCellAPC + ThEffector => bCellBlast:

rate = k2 * bCellApc * ThEffector / (km + ThEffector);
bCellBlast += rate;
bCellAPC -= rate; 

tActivation = 1-3 hours at ThEffector concentration = 1.0e5/ml (sufficient response) Funk1998
(but see: Baumgarth2000, revisit?)

Germinal Center Formation: bCellBlast => bCellCentroblast:

Liu1991: in each follicle: 3-5 (or 10-20 Liu1997) bCellBlast generate 1.2e4 to 1.5e4 bCellCentroblast in 12 divisions, ~6 hours cycle time = 72 hours total, during the fourth day germinal center develops
Germinal center first appears 4-5 days after antigen, maximum cell numbers at 10-11 days and decline after about 3 weeks, Liu1991
See TcNaive clonal expansion for example code
bCellCentroblastPrecursor[11...1], choose kbCentroblastReplicateInitial such that 95% of bCellBlast take the plasma medullary route, and 5% take the bCellCentroblast route. (See bCellPlasmaMedullary)

bCellCentroblastPrecursor + ThEffector + dendriticApc => classSwitch:

This hypothetical model assumes cognate interactions between bCell and thCell and dendritic cell determine isotype switching. Also see tCell polarization.
Note: class switching also occurs in germinal center, however most before germinal center, Toellner1998, Toellner1996.

bCell Isotype Switching Table
Dendritic
il10
thCell Profile Isotype (in %) Notes
th1
ifnGamma
th2
il4
IgA IgM IgG IgE
100% 83% 0% 19 9 72 0 Influenza (live), Sangster1997
100% 1% 40% 0? 40 40 20 Hasbold1998, il4

class switch: 6+ divisions, Deenick1999
dendritic cells (il10) => isotype switch to igA, Fayette1997;
ifnGamma => igG, Snapper1993
Human isotypes: igG1,igG2,igG3,igG4,igA1,igA2,igM,igE, Stavnezer1996

class switch algorithm:
 for all bCellCentroblastPrecursor {
  ifnGamma = ThEffector.profile[TH1] ;
  il4 = ThEffector.profile[TH2] ;
  rate = k2igg * bCellCentroblastPrecursor.profile[IGM] * ifnGamma / (kmigg + ifnGamma) ;
  bCellCentroblastPrecursor.profile[IGM] -= rate ;
  bCellCentroblastPrecursor.profile[IGG] += rate ;    (IgG2)
  il10 = dendriticApc.profile[IL10] ;
  rate = k2iga * bCellCentroblastPrecursor.profile[IGM] * il10 / (kmiga + il10) ;
  bCellCentroblastPrecursor.profile[IGM] -= rate ;
  bCellCentroblastPrecursor.profile[IGA] += rate ;
  rate = k2igg1 * bCellCentroblastPrecursor.profile[IGM] * il4 / (kmigg1 + il4) ;
  bCellCentroblastPrecursor.profile[IGM] -= rate ;
  bCellCentroblastPrecursor.profile[IGG] += rate ;    (IgG1)
  rate = k2ige * bCellCentroblastPrecursor.profile[IGG] * il4 / (kmige + il4) ;
  bCellCentroblastPrecursor.profile[IGG] -= rate ;
  bCellCentroblastPrecursor.profile[IGE] += rate ;
 } 

empirically adjust k2,km to fit table data.

Germinal Center Overview

The model is based on Liu1991, MacLennan1997. Architecturally similar to the germinal center mathematical model of Kesmir1999
Model assumes germinal center collapse within ~2 days unless continual renewal of bCellCentroblasts from centrocytes (which must undergo cognate interaction with fdc and thGerminalCenter). Cyclic re-entry hypothesis. Maclennan1997, Kesmir1999
Centroblasts have a 6-7 hours cell cycle time, centroblasts don’t increase in numbers, instead they migrate to light zone to become centrocytes, Liu1991
Assume total Centrocyte pool size is 15k, broken down as: bCellCentrocyteInitial = 12k, bCellCentrocyteApc = 2500, bCellCentrocyte = 500
(but see: Camacho1998. Also revisit numbers after adding affinity maturation model, Smith1997)

Germinal Center flow kinetics
source destination flow (bCells/sec) Notes
bCellCentroblast Die 0.14 tHalfLife = ~20 hours, Kesmir1999; bCellCentroblast pool size = ~15k
bCellCentroblast bCellCentrocyteInitial 0.6 Liu1991: 6-7hrs cycle time => tHalfLife = 4.85hrs
bCellCentrocyteInitial Die 0.3 tHalfLife = 8 hours, Kesmir1999, GulbransonJudge1997 (total die for all Centrocytes = .36/sec (15k @ thl=8hrs))
bCellCentrocyteInitial bCellCentrocyteApc 0.3 derived: tHalfLife = 8 hours
bCellCentrocyteApc Die 0.06 tHalfLife = 8 hours
bCellCentrocyteApc bCellCentrocyte 0.24 Derived: tHalfLife = 2 hours
bCellCentrocyte bCellCentroblast 0.14 must match “bCellCentroblast => die” for stable germinal center, Derived: tHalfLife = 41min
bCellCentrocyte plasmaCell 0.04 remainder of budget assigned to plasma and memory, derived: tHalfLife = 2.4hr
bCellCentrocyte bCellMemory (recirculating) 0.06 derived: tHalfLife = 1.6hr
bCellCentrocyte bCellMemoryMarginal 0.002 derived: tHalfLife = 48hr

bCellCentroblast => bCellCentrocyteInitial + bCellCentroblast:

See Germinal Center Overview

bCellCentroblast => die:

See Germinal Center Overview
tHalfLife = ~20 hours, Kesmir1999

bCellCentrocyteInitial => die:

See Germinal Center Overview
tHalfLife = 8 hours, Kesmir1999, GulbransonJudge1997

bCellCentrocyteInitial + fdcApc => bCellCentrocyteApc:

Affinity selection ,See Germinal Center Overview

rate = k2 * bCellCentrocyteInitial * fdcApc / (km + fdcApc);
bCellCentrocyteApc += rate;
bCellCentrocyteInitial -= rate;
fdc += kn * rate;
fdcApc -= kn * rate; 

kn = 0.01, assumes 100 IC (immune complexes) per fdcApc; tHalfLife = 8 hours @ fdcapc saturated.
about 75 fdcApc per Germinal center (GC), Tew1997
(but see: Hannum2000, IC not essential on FDC), Lindhout1998: < 4 hours (1-2 hours) to block apoptosis

bCellCentrocyteApc => die:

See Germinal Center Overview
tHalfLife = 8 hours, Kesmir1999, GulbransonJudge1997

bCellCentrocyteApc + thGerminalCenter => bCellCentrocyte:

“Peripheral Tolerance”, See Germinal Center Overview

rate = k2 * bCellCentrocyteInitial * thGerminalCenter / (km + thGerminalCenter);
bCellCentrocyte += rate;
bCellCentrocyteApc -= rate; 

activation time = 1-3 hours, Funk1998
tHalfLife = 2 hours @ thGerminalCenter saturated
thGerminalCenter quantity = 1500/GC, (5-10% of GC cells), Gray1997

bCellCentrocyte => bCellCentroblast:

See Germinal Center Overview
germinal center, light zone, migrate to dark zone, recirculation hypothesis, McHeyzerWilliams1997 page176

rate = k2 * bCellCentrocyte;
[LIMIT FUNCTION (see note)]
bCellCentrocyte -= rate;
bCellCentroblast += rate;

note: limit function: limit rate to amount of cells lost by the
"bCellCentroblast => die" equation 

Model assumes germinal center size is limited by anatomical constraints. Therefore germinal center size can’t exceed its initial “maximum” size. centrocytes “re-entering” the dark zone to become centroblasts can’t increase the size of the germinal center but only “restore” centroblasts lost due to cell death (apotosis)
Maximum rate should equal the rate of “bCellCentroblast => die” = 0.14 bCells/sec, which gives a tHalfLife = 41min. (set at 28min for extra margin)

bCellCentrocyte => plasmaCell:
See Germinal Center Overview

rate = k2 * bCellCentrocyte;
bCellCentrocyte -= rate;
plasmaCell += rate; 

germinal center, light zone, migrate to boneMarrow, etc. type: IgG, IgA, IgM, IgE, Liu1997, McHeyzerWilliams1997
maximum rate = 0.1 cells/sec-gc (divided between plasma cells and memory cells)

bCellCentrocyte => bCellMemory:

See Germinal Center Overview

rate = k2 * bCellCentrocyte;
bCellCentrocyte -= rate;
bCellMemory += rate; 

less than 5% of peak germinal center bCell number survive as memory cells, Smith1997

marginal zone memory, recirculating memory — McHeyzerWilliams1997

bCellCentrocyte => bCellMemoryMarginal:

See Germinal Center Overview

rate = k2 * bCellCentrocyte;
bCellCentrocyte -= rate;
bCellMemoryMarginal += rate; 

marginal zone memory, recirculating memory — McHeyzerWilliams1997

bCellBlast => bCellPlasmaMedullary:

See TcNaive clonal expansion for example code, dispersion = 0.6
Red pulp / medullary cords
7 repetitions @ 6 hours/rep., peak at 48 hours

Cell kinetics, Liu1997
cell appearance time peak ending time
blasts day 0 day 2 day 3
plasmaCell day 1 day 2-4 day 5

5 repetitions in 3 days, Sze2000
6-7 divisions, lasts for three days, Maclennan1997

From Sangster1997: plasmaMedullary = 0.2% of spleen
Liu1991: germinal center = 0.3% of spleen (also Smith1997), primary response (~1% or less secondary response, Liu1991)
therefore: ~95% of bCellBlast => plasmaMedullary, ~5% of bCellBlast => germinal center

Selection between plasma and germinal center (alternative theories): BCR driven, DalPorto1998, Smith1997. McHeyzerWilliams2000: b220-, b220+

il12,il6, Dubois1998

bCellPlasmaMedullary => igM, igG, igA, igE:

rate = k2 * bCellPlasmaMedullary;
igM,igG += rate; 

rate = 2000 igM/sec-cell, Funk1998.
rate = 14,000 igG/sec-cell, Funk1998

bCellPlasmaMedullary => die:

tHalfLife = ~3 days, Maclennan1997
tHalfLife = 3-5 days, McHeyzerWilliams1997
revisit for long-lived plasma cells??

bCellPlasmaMedullary => plasmaCell:

See Wehrli2001, (assume approximately 10% exit lymphNode).

bCellMemory + dendriticApc => bCellMemoryAPC:

rate = k2 * bCellMemory * dendriticApc / (km + dendriticApc);
bCellMemory -= rate;
bCellMemoryAPC += rate; 

k2,km from: Arpin1997: lower threshold than naive (dendriticApc or antigen, revisit)

bCellMemoryMarginal + antigen => bCellMemoryAPC:

rate = k2 * bCellMemoryMarginal * antigen / (km + antigen);
bCellMemoryMarginal -= rate;
bCellMemoryAPC += rate; 

k2,km from: Arpin1997: lower threshold than naive (antigen, revisit)

Peripheral Tolerance: bCellMemoryAPC => (die):

assume the same as naive: tHalfLife = 3 days

Activation: bCellMemoryAPC + ThEffector => bCellBlastMemory:

rate = k2 * bCellMemoryApc * ThEffector / (km + ThEffector);
bCellBlastMemory += rate;
bCellMemoryAPC -= rate; 

4x more than naive, Liu1997. 10x more than naive McHeyzerWilliams1997

bCellBlastMemory => bCellCentroblast:
see Liu1991 figure 4: initially ~5x primary, dies out more rapidly

bCellBlastMemory => bCellPlasmaMedullary:
see Liu1997 figure 8: 3-5x more than primary. 5-8 fold more plasma cells than primary, (homeostatis, “decreasing potential hypothesis”.) Arpin1997

bCellMemory => die:

long lived?

Miscellaneous (dendritic, macrophage, cytokines…)

il2 => die:

half life = ~45 minutes

dendriticAPC => die:

tHalfLife = 1 day ?? (with tCell interaction), Iezzi1999; waits in lymph node

macrophageApc + TcEffector => die:

rate = k2 * TcEffector * macrophageApc;
macrophageApc -= rate;
TcEffector -= rate * N;

Estimate: tHalfLife = 20 minutes at TcEffector = 8000/ul, N = 0.1, Bocharov1994
assumes TcEffector cells destroy infected macrophage and dendritic cells.

dendriticApc + TcEffector => die:

rate = k2 * TcEffector * dendriticApc;
dendriticApc -= rate;
TcEffector -= rate * N;

Estimate: tHalfLife = 20 minutes at TcEffector = 8000/ul, N = 0.1, Bocharov1994, Iezzi1999, Ingulli1997, Knight1997
assumes TcEffector cells destroy infected macrophage and dendritic cells.

macrophageApc => antigen (macrophage die):

rate = k2 * macrophageApc;
macrophageApc -= rate;
antigen += kn * rate; 

Bender1998, tHalfLife = ~24 hours, kn = 2.0 estimate
Assumes macrophages transport antigen from infected tissue to draining lymphNode, die and release antigen for fdc.

antigen + igM => immuneComplex:

rate = k2 * antigen * igM;
antigen -= rate;
igM -= kn * rate;
immuneComplex += rate; 

From Tew1997, kn = 1.0 / 6.02e17
tHalfLife = 10 minutes at igM = 1.7e-10umoles/ul (assume tZone), Bocharov1994

(but see Baumgarth2000, Hannum2000)

fdc + immuneComplex => fdcApc:

rate = k2 * fdc * immuneComplex / (km + immuneComplex);
if (fdcApc > fdcApcTarget) {
  rate = 0; /* LIMIT FUNCTION */
}
fdc -= rate;
fdcApc += rate;
immuneComplex -= kn * rate;

Assume number of fdcApc cells are anatomically constrained to ~0.5% of total germinal center cells, adapted from Tew1997
maximum fdcApc = ~75 cells/GC; kn = 100.0
immuneComplex trapped in fdc within minutes, Tew1997
Assume km saturated at immuneComplex = fdc * 1000.0
set tHalfLife = ~30 minutes @ saturation

Lymph Node Model

Equations unique to the lymph node, such as afferent lymph input

Migration, bCellNaiveRecirculatingLymphInput => bCellNaiveRecirculating:

Rate = k2 * bCellNaiveRecirculatingLymphInput;
bCellNaiveRecirculatingLymphInput -= Rate;
bCellNaiveRecirculating += Rate;

flow = 0.05 ul/sec-gram (from 125 ml/hour per 700 grams)

Migration, macrophageApcLymphInput => macrophageApc:

Rate = k2 * macrophageApcLymphInput;
macrophageApcLymphInput -= Rate;
macrophageApc += Rate;

flow = 0.05 ul/sec-gram (from 125 ml/hour per 700 grams)

Migration, dendriticApcLymphInput => dendriticApc:

Rate = k2 * dendriticApcLymphInput;
dendriticApcLymphInput -= Rate;
dendriticApc += Rate;

flow = 0.05 ul/sec-gram (from 125 ml/hour per 700 grams)

Migration, bCellNaiveRecirculating => bCellNaiveRecirculatingLymphOutput:

Rate = k2 * bCellNaiveRecirculating;
bCellNaiveRecirculating -= Rate;
bCellNaiveRecirculatingLymphOutput += Rate;

output formula missing inflammatory response “shut down”, Mackay1992
tHalfLife = 23 days [revisit] (derived to match efferent flow 1.25e9 cells/hour = 347222/sec, 10% bCells = 34722/sec)

Migration, thNaive => thNaiveLymphOutput:

Rate = k2 * thNaive;
thNaive -= Rate;
thNaiveLymphOutput += Rate;

output formula missing inflammatory response “shut down”, Mackay1992
tHalfLife = 16.3 days [revisit] (derived to match efferent flow)

Migration, tcNaive => tcNaiveLymphOutput:

Rate = k2 * tcNaive;
tcNaive -= Rate;
tcNaiveLymphOutput += Rate;

output formula missing inflammatory response “shut down”, Mackay1992
tHalfLife = 54.7 days [revisit] (derived to match efferent flow)

Migration, igM => igMLymphOutput:

Migration, plasmaCell => plasmaCellLymphOutput:

Migration, thEffector => thEffectorLymphOutput:

Migration, tcEffector => tcEffectorLymphOutput:

Example:
Rate = k2 * tcEffector;
tcEffector -= Rate;
tcEffectorLymphOutput += Rate;

output formula missing inflammatory response “shut down”, Mackay1992
flow = 0.05 ul/sec-gram, tHalfLife = ~3 hours (from 125 ml/hour per 700 grams)

Migration, bCellMemory => bCellMemoryLymphOutput:

Migration, thMemory => thMemoryLymphOutput:

Migration, tcMemory => tcMemoryLymphOutput:

Example:
Rate = k2 * tcMemory;
tcMemory -= Rate;
tcMemoryLymphOutput += Rate;

tHalfLife = ~23 days, estimates from bCellNaiveRecirculate

Migration, bCellMemoryLymphInput => bCellMemory:

Migration, thMemoryLymphInput => thMemory:

Migration, tcMemoryLymphInput => tcMemory:

Example:
Rate = k2 * tcMemoryLymphInput;
tcMemory += Rate;
tcMemoryLymphInput -= Rate;

flow = 0.05 ul/sec-gram (from 125 ml/hour per 700 grams)

Spleen Model

Equations unique to the spleen, such as blood output and marginal zone

Migration, bCellNaive => bCellNaiveBlood:

Rate = k2 * bCellNaive;
bCellNaive -= Rate;
bCellNaiveBlood += Rate;

tHalfLife = 1.5 hours (derived to match steady state input flow rate + cell death, Pabst1988)

Migration, bCellNaiveRecirculating => bCellNaiveRecirculatingBlood:

Rate = k2 * bCellNaiveRecirculating;
bCellNaiveRecirculating -= Rate;
bCellNaiveRecirculatingBlood += Rate;

tHalfLife = 11.7 hours (derived to match steady state input flow rate + cell death, Pabst1988)

Migration, thNaive => thNaiveBlood:

Rate = k2 * thNaive;
thNaive -= Rate;
thNaiveBlood += Rate;

tHalfLife = 2.5 hours (derived to match steady state input flow rate + cell death, Pabst1988)

Migration, tcNaive => tcNaiveBlood:

Rate = k2 * tcNaive;
tcNaive -= Rate;
tcNaiveBlood += Rate;

tHalfLife = 2.1 hours (derived to match steady state input flow rate + cell death, Pabst1988)

bCellNaiveRecirculating => bCellNaiveMarginalZone:

Rate = k2 / (ki + bCellNaiveMarginalZone;
bCellNaiveRecirculating -= Rate;
bCellNaiveMarginalZone += Rate;

Assume anatomically limited and at steady state, rate matches loss rate, Maclennan1997, Maclennan1993

bCellNaiveMarginalZone => die:

Rate = k2 * bCellNaive;
bCellNaiveRecirculating -= Rate;

tHalfLife = 3-5 weeks. Maclennan1997, Maclennan1993, extended indefinitely if no new naive cells.

bloodRbc => die:

tHalfLife = ~120 days, 0.36ul/sec Guyton page 425

platelets => die:

tHalfLife = ~8-12 days, 6.84ul/sec ,Guyton page 436

Migration, monocyteBlood => macrophage:

Migration, monocyteBlood => dendriticImmature:

macrophage => 2 * macrophage:

macrophage => die:

See General Tissue Model

Migration, bCellMemory => bCellMemoryBlood:

Migration, thMemory => thMemoryBlood:

Migration, tcMemory => tcMemoryBlood:

Example:
Rate = k2 * tcMemory;
tcMemory -= Rate;
tcMemoryBlood += Rate;

tHalfLife = ~2.5 hours, estimates from thNaive

Migration, bCellMemoryBlood => bCellMemory:

Migration, thMemoryBlood => thMemory:

Migration, tcMemoryBlood => tcMemory:

Example:
Rate = k2 * tcMemoryBlood;
tcMemory += Rate;
tcMemoryBlood -= Rate;

k2 Based on flow rate of 1151 ul/sec for spleen, Pabst1988

Bronchial Test model

Influenza A model:

From Bocharov1994: “Human influenza is an infection of the upper respiratory tract and
the major central airways.
As the virus multiplies in the epithelium throughout the respiratory tract it causes
degeneration and necrosis.
The pathology, characterized by desquamation of the epithelium, involves the nasal mucosa,
larynx and tracheobronchial tree.
Infection with influenza A virus can result in a spectrum of clinical responses
ranging from an asymptomatic infection to a primary viral pneumonia that rapidly
progresses to a fatal outcome.
The typical uncomplicated influenza syndrome is tracheobronchitis with the additional
involvement of small airways.”

inject => antigenBal:

antigenBal += infectionDose (at time 0);

influenza infectionDose = 2.9e7 particles/ml; equals approximately 10% of epithelia cells in bronchial test region), Bocharov1994

antigenBal => die:

tHalfLife = 14 hours, mucociliary Clearance, Bocharov1994

antigenBal + igABal => die:

rate = k2 * igABal * antigenBal;
antigenBal -= rate;
igABal -= N * rate; (neutralize)

tHalfLifeAntigenBal = 68 min @ igABal = 1.7e-10 umole/ul; N = 10 molecules, Bocharov1994 (rate constant = 8.6e9-8.6e12 ul/umole-day, use 8.6e10)

igABal => die:

tHalfLife = 6 days

Epithelium equations

epitheliaDead => epitheliaCell:

tissue regeneration, fibroblasts. Assumes epithelia region is anatomically constrained. New epithelia cells can only replace dead cells

rate = k2 * epitheliaDead;
epitheliaCell += rate;
epitheliaDead -= rate;

tHalfLife: 5 hours, Bocharov1994

epitheliaCell + antigenBal => epitheliaApc:

Infection

rate = k2 * epitheliaCell * antigenBal;
epitheliaApc += rate;
epitheliaCell -= rate;
antigenBal  -= N * rate;

N = 10; tHalfLife = 1.7 hours at antigenBal = 1.0e7 particles/ul, Bocharov1994 (rate constant = 5.9e11 ul/umole-day)

epitheliaCell + interferonAlpha => epitheliaResistive:

Rate = K2 * epitheliaCell * interferonAlpha;
epitheliaResistive += Rate;
epitheliaCell -= Rate;
interferonAlpha -= N * rate;

N = 10 molecules = 1.3e-7 iu; tHalfLife = 1 hours at interferonAlpha = 0.05 iu/ul, from Bocharov1994 (tc->tr = 1 hour, nsufi = 10-100 iu/ml)

epitheliaCell => die:

rate = k2 * epitheliaCell;
epitheliaCell -= rate;
epitheliaDead  += rate;

k2 from: HL = ~30hours, Stites 678,679

epitheliaResistive => epitheliaCell:

Rate = K2 * epitheliaResistive;
epitheliaResistive -= Rate;
epitheliaCell += Rate;

tHalfLife = ~24 hours, Bocharov1994

epitheliaApc => epitheliaDead:

rate = k2 * epitheliaApc;
epitheliaApc -= rate;
epitheliaDead += rate;

tHalfLife = ~16 hours, Bocharov1994

epitheliaApc => antigenBal:
virus replication

rate = k2 * epitheliaApc;
antigenBal += rate;

production rate = ~7000 virus particles/day-cell, Bocharov1994 (6000/day)

epitheliaApc + TcEffector => die:

rate = k2 * TcEffector * epitheliaApc;
epitheliaApc -= rate;
epitheliaDead += rate;
TcEffector -= rate * N;

tHalfLife = 20 minutes at TcEffector = 8000/ul, N = 0.05, adapted from Bocharov1994

TcEffector => die:

ThEffector => die:

rate = k2 * TcEffector;
TcEffector -= rate;

tHalfLife = 20 hours, AICD, placeHolder for now, revisit… Swain1996

macrophage + antigenBal => macrophageApc:

rate = k2 * macrophage * antigenBal;
macrophageApc += rate;
macrophage -= rate;
antigenBal  -= N * rate;

N = 5; tHalfLife = 1 hours at antigenBal = 1.0e7 particles/ul, Bocharov1994 (rate constant = 1.4e13-1.4e11 ul/umole-day)

macrophageApc => interferonAlpha:

Rate = k2 * macrophageApc;
interferonAlpha += Rate;

generation, 2.0e-4 iu/day-cell, Bocharov1994 (0.17 molecules/sec), 0.15 molecules/sec Lehmann1996

interferonAlpha => die:

tHalfLife = ~42 minutes

macrophageApc => tnfAlpha:

Rate = k2 * macrophageApc;
tnfAlpha += Rate;

generation, 155 molecules/sec-cell, Lehmann1996

tnfAlpha => die:

tHalfLife = ~45 minutes, estimate

Interstitium equations

Activation/Polarization: dendriticImmature + antigenBal => dendriticAPC:
Hypothetical third signal model algorithm. Kalinski1999. See tCell polarization.

Dendritic Polarization Table
Antigen il12 il10
influenza 100% 100%
Ryegrass 0% 100%
rate = k2 * dendriticImmature * antigenBal;
dendriticApc += rate;
dendriticImmature -= rate;
antigenBal  -= N * rate;

N = 5; tHalfLife = 1 hours at antigenBal = 1.0e7 particles/ul, assumes same as macrophage

plasmaCell => igABal,igE:

rate = k2 * plasmaCell.profile[IGA];
igABal += rate;

generation, igA = 13,000 molecules/sec-cell, Funk1998

igE = 11,000 molecules/sec-cell, extrapolated from Funk1998

igE => die:

tHalfLife = 2 days

plasmaCell => die:

tHalfLife = 3 weeks, Maclennan1997

TcEffector + !dendriticApc => TcMemory:

rate = k2 * TcEffector / (1.0 + dendriticApc / km);
TcEffector -= rate;
TcMemory += rate;

MuraliKrishna1998: only about 1% survive. (also see Zinkernagel1996)

tHalfLife = estimate 1000 hours. km = 10k/ml estimate.

thBlast + !dendriticApc => ThMemory:

ThEffector + !dendriticApc => ThMemory:

rate = k2 * ThEffector / (1.0 + dendriticApc / km);
ThEffector -= rate;
ThMemory += rate;

Assume same as tcMemory.

Activation, ThMemory + dendriticApc => thBlast:

rate = k2 * dendriticApc * thMemory / (km + dendriticApc);
thBlast += rate;

See tcMemory activation (lymphNode).

1-6 hours, activation time, Lalvani1997, Iezzi1998

thBlast + dendriticApc => il5:

rate = k2 * dendriticApc * thBlast;
il5 += rate;

9600 molecules/sec @ dendriticApc = 1000/ml, loosely adapted from Swain1996, Horie1996, and asthma timelines

asthma: il5: 80% tCell, 15% eosinophil, 11% mast, Moqbel1994

thBlast + dendriticApc => il3:

rate = k2 * dendriticApc * thBlast;
il3 += rate;

6000 molecules/sec @ dendriticApc = 1000/ml (placeHolder, adapted from il5)

macrophageApc => bloodGmcsf:

Rate = k2 * macrophageApc;
bloodGmcsf += Rate;

generation, 1.3e4 molecules/sec-cell, adapted from Petros1992 (assume at serum = 1ng/ml, MW=~50k, thl=2 hours, #macrophageApc = ~500k)

macrophageApc => die:

tHalfLife = ~24 hours, Bender1998

macrophageApc => macrophageApcLymphOutput:

Rate = k2 * macrophageApc;
macrophageApc -= Rate;
macrophageApcLymphOutput += Rate;

flow = 6.25e-3 ul/sec

dendriticApc => dendriticApcLymphOutput:

Rate = k2 * dendriticApc * (inflammatoryOutputRate?);
dendriticApc -= Rate;
dendriticApcLymphOutput += Rate;

flow = 6.25e-3 ul/sec, from lymphatics compartment schematic, (30ml/hr (lungs) * 7.5e-4 (bronchial test portion))
increased by inflammatoryOutputRate? Revisit

macrophageApc + TcEffector => die:

rate = k2 * TcEffector * macrophageApc;
macrophageApc -= rate;
TcEffector -= rate * N;

Estimate: tHalfLife = 20 minutes at TcEffector = 8000/ul, N = 0.1, Bocharov1994
assumes TcEffector cells destroy infected macrophage and dendritic cells.

dendriticApc + TcEffector => die:

rate = k2 * TcEffector * dendriticApc;
dendriticApc -= rate;
TcEffector -= rate * N;

Estimate: tHalfLife = 20 minutes at TcEffector = 8000/ul, N = 0.1, Bocharov1994, Iezzi1999, Ingulli1997, Knight1997
assumes TcEffector cells destroy infected macrophage and dendritic cells.

mastNaive + igE => mastCell:

rate = k2 * mastNaive * igE;
mastCell += rate
mastNaive -= rate;
igE -= rate * N;

N = 300k/6.02e17 umoles, Metcalfe1997, 300k receptors/cell

k2 from tHalfLife = 68 minutes @ igE = 1.7e-10 umoles/ul adapted from Bocharov1994

mastCell + antigen => mastCellDegranulated,histamine:

rate = k2 * mastCell * antigen;
mastCellDegranulated += rate
mastNaive -= rate;
histamine += rate * N1;
antigen -= rate * N2;

N1 = 1.6e10/6.02e17 umoles, Metcalfe1997, 3-8pg histamine/cell, molecular weight = 111 (c5h9n3)

N2 = 30k particles, Metcalfe1997, maximum histamine release at 30k receptors/cell occupied. (minimal at 100 receptors), internalized within 6-10 minutes

k2 from: high affinity = 8.6e11 ul/umoles-day => tHalfLife = 5.8 minutes @ antigen = 1.2e8 particles/ul adapted from Bocharov1994

histamine => die:

tHalfLife = 15 minutes, 13-96minutes, Erjavec1986, Irmanflorjanc1994

mastCellDegranulated => die:

tHalfLife = 1 day, placeHolder

mastNaive => die:

tHalfLife = 20 days, Kiernan1979

mastCell => die:

tHalfLife = 20 days, Kiernan1979

eosinophil + il5 => ltc4:

rate = k2 * eosinophil * il5^4;
ltc4 += rate

k2 from: 200 molecules/second @ il5 = 12 ng/ml (adapted from Wenzel1990, also see Horie1996, Moqbel1994)

ltc4 molecular weight = 625, Murphy1982 p.201

currently placeHolder equation “curve-fit” to match late response timelines. Hill equation with N > 1
revisit: see Laviolette1995

eosinophil => die:

tHalfLife = 11 weeks, Weller1991, (but see Yamaguchi1994, half life vs. il5)

ltc4 => die:

tHalfLife = 20 minutes, 10-20 minutes estimate, Wenzel1990

il3 => die:

tHalfLife = ~35 minutes, Khwaja1994

il5 => die:

tHalfLife = ~45 minutes

Migration, il3 => il3Blood:
Migration, il5 => il5Blood:

Rate = k2 * il3;
il3 -= Rate;
il3 += Rate;

tHalfLife = ~15 minutes, placeHolder

Inflammatory Response:
for inflamed tissues generating tnfAlpha from macrophages

inflammatoryRate = 1.0 + kn * tnfAlpha / (km + tnfAlpha);

kn = 160, adapted from McWilliam1994, Flynn1999, (9x VanFurth1989)
km = 3.0e-7 umoles/ml (6ng/ml), adjusted to match Flynn1999 data

Inflammatory Output Response:
for inflamed tissues generating tnfAlpha from macrophages

inflammatoryOutputRate = 1.0 + kn * tnfAlpha / (km + tnfAlpha);

kn = 9 estimate, McWilliam1994
km = 3.0e-7 umoles/ml (6ng/ml)

Inflammatory il3 Response:

il3inflammatoryRate = 1.0 + kn * il3

kn = 4.0 @ il3 = 1.1e-7 umoles/ml, placeHolder

Inflammatory il5 Response:

il5inflammatoryRate = 1.0 + kn * il5

kn = 5.0 @ il5 = 3.3e-8 umoles/ml, placeHolder

Migration, eosinophilBlood => eosinophil:

Rate = k2 * eosinophilBlood * il5inflammatoryRate;
eosinophilBlood -= Rate;
eosinophil += Rate;

Also See General Tissue Model

Migration, mastCellBlood => mastNaive:

Rate = k2 * mastCellBlood * il3inflammatoryRate;
mastCellBlood -= Rate;
mastCell += Rate;

Also See General Tissue Model

Migration, bCellNaiveRecirculatingBlood => bCellNaiveRecirculating:

Migration, ThEffectorBlood => ThEffector:

Migration, TcEffectorBlood => TcEffector:

Migration, plasmaCellBlood => plasmaCell:

Rate = k2 * plasmaCellBlood * inflammatoryRate;
plasmaCellBlood -= Rate;
plasmaCell += Rate;

Also See General Tissue Model

Migration, bCellNaiveRecirculating => bCellNaiveRecirculatingLymphOutput:

Rate = k2 * bCellNaiveRecirculating * inflammatoryRate;
bCellNaiveRecirculating -= Rate;
bCellNaiveRecirculatingLymphOutput += Rate;

Also See General Tissue Model

Migration, monocyteBlood => dendriticImmature:

Migration, monocyteBlood => macrophage:

Rate = k2 * monocyte * inflammatoryRate;
monocyte -= Rate;
macrophage += Rate;

Also See General Tissue Model

Migration, thBlast => thMemoryLymphOutput: (assume same as thMemory)

Migration, bCellMemory => bCellMemoryLymphOutput:

Migration, thMemory => thMemoryLymphOutput:

Migration, tcMemory => tcMemoryLymphOutput:

Example:
Rate = k2 * tcMemory * inflammatoryOutputRate;
tcMemory -= Rate;
tcMemoryLymphOutput += Rate;

Also See General Tissue Model

Migration, bCellMemoryBlood => bCellMemory:

Migration, thMemoryBlood => thMemory:

Migration, tcMemoryBlood => tcMemory:

Example:
Rate = k2 * tcMemoryBlood * inflammatoryRate;
tcMemory += Rate;
tcMemoryBlood -= Rate;

Also See General Tissue Model

macrophage => 2 * macrophage:

dendriticImmature => 2 * dendriticImmature:

Example:
if ((macrophage + macrophageApc) < macrophageInitial) {
    Rate = k2 * macrophage;
    macrophage += Rate;
} /* if */

Assume anatomically constrained, revisit?
il4 based? Bertorelli2000

Also See General Tissue Model

macrophage => die:

dendriticImmature => die:

See General Tissue Model

General Tissue Model

Equations for tissues not under investigation (mostly migration)

Migration, bCellNaiveRecirculatingBlood => bCellNaiveRecirculating:

Migration, ThEffectorBlood => ThEffector:

Migration, TcEffectorBlood => TcEffector:

Migration, plasmaCellBlood => plasmaCell:

Tissue Migration
tissue Effector cells: ThEffectorBlood, TcEffectorBlood, plasmaCellBlood bCellNaiveRecirculatingBlood
ul/sec Note1 %total Note1 ul/sec Note2
Liver 5.2 15 77 * 11.3 / 700
Skin 3.5 10 7 * 11.3 / 700
Miscellaneous 5.2 15 175 * 11.3 / 700
Respiratory Tract 6.9 20 168 * 11.3 / 700
Bronchial Test 6.9 * 7.5e-4 168 * 7.5e-4 * 11.3 / 700
Intestines 6.9 20 273 * 11.3 / 700
boneMarrow 6.9 20  

Note1: Effector Cells: From Binns1992: percentage of 125 ml/hr, (see migration pattern worksheet, and lymphatic compartments schematic)
Note2: total all tissues = 11.3 ul/sec, derived to match afferent flow concentration to draining lymph node. (see lymphatic compartments schematic)

Rate = k2 * plasmaCellBlood;
plasmaCellBlood -= Rate;
plasmaCell += Rate;

Migration, bCellNaiveRecirculating => bCellNaiveRecirculatingLymphOutput:

Tissue Migration
tissue flow ul/sec volume ul cells/sec tHalfLife days
Liver 2.3 1,600,000 total 231 5.6
Skin 10.5 3,800,000 total 21 3.1
Miscellaneous - - 525 306
Respiratory Tract 0.36 640,000 interstitium 0.38 17.5
Bronchial Test 0.36 480 interstitium 0.38 17.5
Intestines - - 819 133.0
boneMarrow - - - -
Rate = k2 * bCellNaiveRecirculating;
bCellNaiveRecirculating -= Rate;
bCellNaiveRecirculatingLymphOutput += Rate;

Derived to match blood -> internal cell flows at steady state. Revisit, as the numbers for miscellaneous and intestines look incorrect.

Migration, mastCellBlood => mastNaive:

Migration, eosinophilBlood => eosinophil:

Migration, monocyteBlood => dendriticImmature:

Migration, monocyteBlood => macrophage:

Tissue Migration
tissue macrophage dendritic Mast Eos
ul/sec Note1 %total Note1 ul/sec Note2 ul/sec ul/sec Note3
Liver 50 53 - - -
Skin - - - - -
Miscellaneous - - - - 104.8
Respiratory Tract 14 15 - 267 0.13
Bronchial Test 14 * 7.5e-4 0.14 * 7.5e-4 267 * 7.5e-4 0.13 * 7.5e-4
Intestines 7 7 - - -
boneMarrow - - - - -
Spleen 24 25 - - -
lymphNode - - - - -
Rate = k2 * monocyteBlood;
monocyteBlood -= Rate;
macrophage += Rate;

Note1: From VanFurth1989: percentage of 95 ul/sec, (4465 cells/sec)
Note2: matches steady state, revisit

Note3: 105ul/sec total

macrophage => 2 * macrophage:

tHalfLife = 1 days (anatomically constrained?) (respiratory tract, bronchial test, intestines) otherwise zero, adapted from VanFurth1989

macrophage => die:

tHalfLife = 4 days, adapted from VanFurth1989

dendriticImmature => 2 * dendriticImmature:

tHalfLife = 1 days (anatomically constrained? ) (respiratory tract, bronchial test, intestines) otherwise zero, adapted from Lambrecht1998

il4 based? Bertorelli2000

dendriticImmature => die:

tHalfLife = 3 days, adapted from Lambrecht1998

plasmaCell => die:

tHalfLife = 3 weeks, Maclennan1997; 3-6 weeks, McHeyzerWilliams1997

ThEffector => die:

TcEffector => die:

rate = k2 * TcEffector;
TcEffector -= rate;

tHalfLife = 20 hours, AICD, placeHolder, revisit… Swain1996

ThEffector + !dendriticApc => ThMemory:

TcEffector + !dendriticApc => TcMemory:

rate = k2 * TcEffector / (1.0 + dendriticApc / km);
TcEffector -= rate;
TcMemory += rate;

MuraliKrishna1998: only about 1% survive. (also see Zinkernagel1996)

tHalfLife = estimate 1000 hours. km = 10k/ml estimate.

Migration, bCellMemory => bCellMemoryLymphOutput:

Migration, thMemory => thMemoryLymphOutput:

Migration, tcMemory => tcMemoryLymphOutput:

Example:
Rate = k2 * tcMemory;
tcMemory -= Rate;
tcMemoryLymphOutput += Rate;

tHalfLife = ~4 days estimate

Migration, bCellMemoryBlood => bCellMemory:

Migration, thMemoryBlood => thMemory:

Migration, tcMemoryBlood => tcMemory:

Example:
Rate = k2 * tcMemoryBlood;
tcMemory += Rate;
tcMemoryBlood -= Rate;

Estimate: k2 Based on flow rate of effector cells.

boneMarrow/thymus Model

bloodGmcsf => die:

tHalfLife = ~2 hours, Petros1992, (actually 5 minutes in blood, 2 hours in tissue)

bloodil3 => die:

tHalfLife = ~35 minutes, Khwaja1994

bloodil5 => die:

tHalfLife = ~45 minutes

boneMarrow => mastCellBlood:

rate = k2 * (1.0 + kn * bloodil3 / (km + bloodil3));
mastCellBlood += rate;

generation/migration, k2 => tHalfLife blood = 3.9 hours, 160/sec
km = 2ng/ml, estimated from Khwaja1994
kn = 1.0, placeHolder for now

boneMarrow => eosinophilBlood:

rate = k2 * (1.0 + kn * bloodil5 / (km + bloodil5));
eosinophil += rate;

generation/migration, k2 => tHalfLife blood = 9 hours, 21393/sec (from Stites p.184; Weller1991: tHalfLife = 11 weeks, tissue levels = several hundred times blood level)
km = 1ng/ml, placeHolder
kn = 3.0, placeHolder for now

boneMarrow => monocyteBlood:

rate = k2 * (1.0 + kn * bloodgmcsf / (km + bloodgmcsf));
monocyteBlood += rate;

generation/migration, k2 => tHalfLife = 10-12 hours, 4446/sec
kn = 2 (3x increase in 24 hours, normal at 96 hours, VanFurth1989, McWilliam1994)
km = 2.0e-9 umole/ml, assume saturated at gmcsf = 1ng/ml, Petros1992

boneMarrow => rbcBlood:

rate = k2;
rbcBlood += rate;

generation/migration, tHalfLife = ~120 days, 1.8e6/sec

boneMarrow => plateletsBlood:

rate = k2;
plateletsBlood += rate;

generation/migration, thl = 8-12days, 1.9e6/sec

boneMarrow => bCellNaiveBlood:

rate = k2;
bCellNaiveBlood += rate;

generation/migration
estimate 5-10% of total b lymphocyte population/day = ~3e10 cells/day, Janeway P. 214

Thymus => ThNaiveBlood:

rate = k2;
ThNaiveBlood += rate;

Berzins1998: total tCell rate = ~.7% of total tCell population per day (thymus generation: cd4/cd8 ratio = ~3.5/1; in periphery cd4/cd8 ratio = ~2/1 typical) (thNaive generation: .78 * .007 * 1.2e12/day), (tcNaive generation: .22 * .007 * 1.2e12/day)

Thymus => TcNaiveBlood (thymus):

rate = k2;
TcNaiveBlood += rate;

see ThNaiveBlood

Migration, plasmaCellBlood => plasmaCell:

rate = k2 * plasmaCellBlood;
plasmaCell += rate;
plasmaCellBlood  -= rate;

in boneMarrow, MacLennan1997
up to 90% of IgG production from boneMarrow, Janeway P.219, see General tissue

plasmaCell => IgGBlood:

rate = k2 * plasmaCell.profile[IGG];
IgGBlood += rate;

generation, 14,000/sec

plasmaCell => die:

tHalfLife = 3-6 weeks, McHeyzerWilliams1997

plasmaCell => IgMBlood:

rate = k2 * plasmaCell.profile[IGM];
IgMBlood += rate;

generation, 2,000/sec

IgMBlood => die:

tHalfLife = 5 days

IgGBlood => die:

tHalfLife = 23 days

ThEffector + !dendriticApc => ThMemory:

TcEffector + !dendriticApc => TcMemory:

See General Tissue Model

Results:

Influenza A (primary and secondary response) Results:

This initial simulation studies the kinetic characteristics of an “uncomplicated” influenza A virus infection.
See Bocharov1994.

primary

Influenza A Primary Response simulation output, starting with an initial infectious dose of 2.9e7 particles/ml.

Infection was cleared in approximately 9 days, which matches Flynn1999.

From simulation results, viral clearance appears to be quite sensitive to migration kinetics.
The “inflammationRate” variable
from tnfAlpha (see inflammationRate, Bronchial Tissue model, inflammatory response)
was “curve fit” to match the Flynn1999 data. The current value needs to be re-visited.

secondary

Influenza A Secondary Response simulation output.
Continuing from the primary response, on day 28, plasma cells and igA were removed from tissues.
And an infectious dose of 2.9e7 virus particles/ml was added.

Infection was cleared in approximately 7 days, which matches Flynn1999.

Encouragingly, in both the primary and secondary responses, the “qualitative” shape/timeline
of the germinal center response curves match the Liu1991 data.
Hopefully indicating that the lymph node model is generally correct.

As with the primary response various variables (inflammationOutputRate, bCellPlasmaMedullary => plasmaCell rate coefficient)
were “curve fit” to match the Flynn1999 data.

The secondary response model is still incomplete. Unresolved is the homeostatsis of memory cells.
Why doesn’t a particular strain overwhelm the memory repertoire, or die out? Also, recirculating memory cells
appear to be insufficient to generate a secondary response. It was necessary to add a bCellMemoryMarginal pool
in order to generate a sufficient bCell response. The tCell response also required adjustment.
tCellEffector -> tCellMemory was adjusted to generate a sufficient tCell response.
Do memory cells, upon activation in tissues, replicate? Currently they only replicate in lymph nodes, as this generates a timeline which matches the Flynn1999 data.
If memory cells replicate in tissues it would appear to cause viral elimination much earlier than the Flynn data would seem to indicate.

Appendix A: Tables

Fluid in the Body 
Compartment Name volume
liters
% of Body Weight % Of Total Body Water
Extracellular total 14 20% 33%
Blood Total 5.4    
Blood Plasma 3.0 (4.3%) (7%)
Blood Erythrocytes 2.4    
Interstital 11 (15.7%) (26%)
Intracellular 28 40% 67%
Total Body Water 42 60% 100%

Notes:

  • Guyton P.306: extracellular = 16liters, intracellar = 32 liters, total body = 48 liters
  • Vander P.7: extracellular = 14liters (interstital = 11L, plasma = 3L), intracellar = 28 liters, total body = 42 liters (60% body weight)
  • Vander P.372: hemocrit = 45% men, 42% women, blood total = 5.4L, erythrocytes = 2.4L
  • Shargel page.52
Vessel Compartment Values
Cardiovascular vessels
compartment Name Flow, mm3/msec Volume, mm3
Total Plasma
Pulmonary Capillary 82.5 864000 475200
Vena Cava 82.5 3432792 1888036
Aorta 82.5 702000 361100
Cerebral capillary 12.5 55621 30592
Hypophyseal portal 0.01 118 65
Hepatic sinusoid 21.7 105458 58002
Portal Vein 17.5 23090 12700
Splenic Capillary 2.5 6075 3341
Glomular Capillary 20.0 88994 40047
Generic Capillary 28.3 119852 65919
Blood reservoir   5400000 2970000
Total 82.5 5400000 2970000
Lymphatic vessels
compartment Name Flow, ml/hour Volume, mm3
Total
Thoratic Duct 5 125.0 200000
Thoratic Duct 4 125.0 100000
Thoratic Duct 3 125.0 100000
Thoratic Duct 2 125.0 100000
Thoratic Duct 1 125.0 100000
HepaticAfferent 14.0 362000
SubcutaneousAfferent 1.3 227000
MiscAfferent 31.0 9.7e6
MediastinalAfferent 30.0 300000
TestMediastinalAfferent 2.1 225? 21000?
MesentericAfferent 49.0 372000
Interstitial reservoir   11500000
Total 125.0 11500000

Notes:

  • cardiovascular:
    1. total flow: 75bpm 66ml stroke vol. = 4.9L/min = 82500 mm^3/sec, (actually derived from Guyton P. Page162, aorta: cross-sectional area,velocity)
    2. references: flow information: Guyton P.200, Greger P.2439, (hypophyseal portal: Greenspan P.97-99)
    3. references: volume information: Guyton P.162, pulmonary:9%, heart:7% (note:combine heart with pulmonary), arteries:13%, capillary:7%, veins:64%, total:5.4e6mm3
      hemocrit = 45% => plasma volume = 5.4e6 * .55 = 2.97e6
    4. blood reservoir: “temporary placeHolder” common pool for blood cells etc. (for now, speeds up simulation)
  • lymphatic:
    1. References: see Schematic of Lymphatic compartments
    2. Chylomicron lymph flow latency: approximately 2 hours
    3. Efferent volume: .6? liters lymph, derived from simulation: ~9hours to remove chylomicrons from lymph
    4. assume Afferent volume = interstital fluid, see organ compartment values table (below)
    5. peritoneal cavity = ~2-3 liters, estimate from Yuan1994
    6. thoratic duct volume numbers are rough “place holders” for now
    7. Interstitial reservoir: “temporary placeHolder” for glucose, tsh, etc.
Organ Compartment Values 
Compartment Name Weight
kilograms
Total volume
ml
blood flow
ml/min
lymphatic flow
ml/hour
interstital volume
ml
vascular volume
ml
Spleen total 0.150 150 150 0 ?  
tZone (pals) 0.021   - - - -
follicle 0.006   - - - -
Marginal Zone 0.011   - - - -
red pulp 0.112   - - - -
Lymph Nodes total 0.7 700.0   125 ?  
tZone (pals) 79%   - - - -
follicle 21%   - - - -
Small Intestine Total 1.6 2147   45 372  
Epithelium -   - - - -
Lamina propria -   - - - -
Peyer’s patches -   - - - -
Lung Total 1.1 999 4950 30 300  
Broncho Alveolar space (BAL) - 560 - - - -
Epithelium - 800 - - - -
Interstitium - 640 - - - -
Bronchial test segment Total       2.1 21?  
Broncho Alveolar space (BAL) - 0.42 - - - -
Epithelium - 0.6 - - - -
Interstitium - 0.48 - - - -
Bone / Bone Marrow 9.8       279  
Skin 4.0 3.8e3 500 1.3 227  
Liver 1.6 1809 1300 14 362  
Thymus            
Brain 1.4   750      
Heart 0.3 300 250   43  
Kidneys 0.3 284 1200   97  
Skeletal Muscle 35.0 2.6e4 1000   4558  
Fat 10.0          
connective tissue 4.9          
adrenals 0.014          
thyroid 0.028          
Total Body 70.0   4950 125 11000  

Notes:

  • miscellaneous:
    • References:
      • References: Greger p.2439 (Blood flows, weights)
      • Shargel page 68
      • Zhu1996, volumes
      • References lymphatic flows: see Schematic of Lymphatic compartments
  • Compartment:
    1. spleen:
      • Chadburn2000: spleen volume: 75% red pulp, 25% white pulp
      • volumes derived from cell distribution (percentage of white pulp): tzone = 55%, follicle = 16%, marginal zone = 28%, 1.8e9 lymphocytes/gram of white pulp
    2. lymphNode:
      • Marchuk1991
      • 600-800grams, 1% of body mass, 500-1000 lymph nodes in body
      • volumes derived from cell distribution: tzone = 79%, follicle = 21%
    3. Small Intestine:
      • surfaceArea = ~100m2, Pabst1987, 200m2 Shargel p.when 13 ,300m2 Faria1999, 1e11 Lymphoid cells/meter Faria 1999
      • 13-20 intra-epithelia lymphocytes per 100 epithelia cells, Pabst1987 = 2.7e11 epithelia cells in small Intestine
      • bacteria = ~1.0e12/gram-stool ? Faria 1999?
    4. Lung:
      • Bocharov1994, Crapo1982
      • surfaceArea = 70-90m2 = 8.0e7mm2
      • bal thickness = 7um, volume = 560ml
      • epithelium thickness = 10um, volume = 800ml
      • interstitium thickness = 8um (placeHolder), volume = 640ml
      • surfaceArea of epithelia cell = 500um2, ~2000 epithelia cells / mm2; total epithelia cells in lung: 1.6e11
    5. bronchial test segment:
      • Bocharov1994
      • surfaceArea = 6.0e4 mm2 = 0.075% of lung; (scale lungs values by 7.5e-4)
      • bal thickness = 7um, volume = .42ml
      • epithelium thickness = 10um, volume = .6ml
      • interstitium thickness = 8um (placeHolder), volume = .48ml
    6. Skin:
      • Goldsmith1990
      • surfaceArea = weight^.425 * height^.725 * 71.84; averageSurfaceArea = 1.7 square meters
      • average thickness = 2.23mm; density = 1.102 gm/ml (assumes skin is 70% water + 30% protein)
B-Cell Pools Worksheet 
Pool Total Cells Subset Plasma B1 (cd5)
Total Naive
%
Recir.
%
Memory
%
Blood 3.4e9 3.4e9 65 30 5 0  
Lymph Fluid efferent 5.0e8 5.0e8       0  
afferent 4.7e8 4.7e8       0  
Peritoneal Cavity 8.3e7 8.3e7       0  
Spleen total 3.5e10         ?  
tZone (pals)   7.0e9 50   50?    
follicle   1.3e10   100      
Marginal Zone   1.5e10 100        
red pulp              
Lymph Nodes 2.3e11 2.1e11 52 48   2.1e10  
Bone Marrow 4.5e10 2.5e10       total:2.0e10
IgA:4.4e9
IgM:4.3e9
IgG:1.1e10
 
Small Intestine Total              
Epithelium 1.0e8 1.0e8       0  
Lamina propria 3.5e10 7.5e9       total:2.8e10
IgA:1.3e10
IgM:9.5e9
IgG:5.4e9
 
Peyer’s patches 6.0e9 6.0e9       0  
Lung Total              
BronchoAlveolar space (BAL) 4.8e5         0  
Epithelium 2.4e8         0  
Interstitium 9.0e8         ?  
Skin 8.0e6 8.0e6       0  
Liver 1.6e8 1.6e8       0  
Thymus 5.0e8 5.0e8       0  
Misc Tissue 2.0e10 2.0e10       0  
Total Body 3.7e11            

Notes:

  • miscellaneous:
    • References:
    • Adapted from Westermann1992 fig.2, table1 (except for below, especially lymphNode)
    • Seabrook1999: Afferent lymph composition = interstitial fluid composition
    • Others: Guyton, Janeway, Pabst1988, Pabst1995
  • Plasma Cells:
    • Funk1998
    • 1 igA plasma cell generates: ~13,000 molecules/second
    • 1 igG plasma cell generates: ~14,000 molecules/second
    • 1 igM plasma cell generates: ~2,000 molecules/second
  • individual strains:
    • Janeway p. 404,311
    • bCells: 1:1.0e4 to 1:1.0e6
    • tCells: 1:1.0e4 to 1:1.0e6
  • Pool:
    1. Blood: 5.4L blood * 2544cells/ul = 1.37e10 cells, Janeway P.67; naive vs. recirculating % loosely derived from Young1999
    2. Lymph Fluid:
      • EfferentConcentration = 1.0e7 cells/ml = thoraticDuctCellsPerHour / thoraticDuctFlow
      • AfferentLymphConcentration = 1.0e6 cells/ml (Seabrook1999)
      • Percentages between afferent (85%), PeritonealCavity (15%) estimate from Yuan1994
    3. Spleen: Percentages from: MacLennan1993: 20% tZone, 36% follicle, 44% marginal zone
    4. lymphNode:
      • Marchuk1991: germinal center diameter = .1 to .3 mm
      • Marchuk1991: cells/gram of lymphNode: bCells: 3.0e8; plasma: 3.0e7; tCells: 1.4e9 (th:7.0e8, tc:7.0e8, thfollicle:1.0e7); macrophage: 3.3e6; macrophageApc: 2-8e5, idc=1.6e7; dendritic:1.6e7
    5. boneMarrow: plasma cells: quantities to generate average Ig blood levels.
    6. Small Intestine:
      • Percentages between Epithelium (60%), LaminaPropria (25%), PeyersPatches (15%), Pabst1987?
      • LaminaPropria: plasma cells: derived from Elson1997 (3-4 grams IgA produced/day): igA: 70-90%, IgM: 5-15%, igG: 3-5%
    7. Lung:
      • BAL concentrations (Velluti1984): macrophage:138k/ml, lymphocytes:17k/ml, neutrophil:1.3k/ml, eosinophils:0.7k/ml
      • BAL (9.5e6 lymphocytes), Epithelium (2.4e10 lymphocytes (Westermann1992: 15lymphocytes/100 epithelia cells)), Interstitium (6.0e9)
    8. Skin: 8.0e8 cells = 2.0e5 cells/gram (Seabrook1999) * 4000 grams
    9. Liver: .5e9 / 35% (derived from Westermann1992, NT cells) = 1.4e9 cells
    10. MiscTissue: Percentages between bCells (50%), tCells (50%) are place holders for now
    11. Total Body: lymphocytes = order of 1.0e12 cells, Stites page 43. Total bCells: ~9.0e11, Rolink1993
T-Cell Pools Worksheet 
Pool Total Cells Th (cd4) Tc (cd8) Gamma
Sigma
Total Naive
%
Memory
%
Total Naive
%
Memory
%
Blood 1.0e10 6.9e9 23 77 3.4e9     0.0
Lymph Fluid efferent 4.8e9 3.3e9 85 15 1.0e9     5.0e8
afferent 7.0e9 3.7e9     1.9e9     1.4e9
Peritoneal Cavity 1.6e9 4.1e8     9.9e8     1.7e8
Spleen Total 3.5e10   69 31       0.0
tZone (pals) 3.0e10 2.3e10     7.0e9      
follicle 1.0e9 1.0e9     0      
Marginal Zone 4.0e9 3.3e9     7.0e8      
red pulp                
Lymph Nodes 9.8e11 4.9e11 90 10 4.9e11     9.5e9
Bone Marrow 2.5e10 1.0e10 0 100 1.5e10     0.0
Small Intestine Total 3.5e10              
Epithelium 1.0e10 1.5e9 33 67 8.5e9     0.0
Lamina propria 1.8e10 1.3e10 33 67 5.0e9     0.0
Peyer’s patches 6.8e9 4.5e9 100 0 1.5e9     7.5e8
Lung Total                
BronchoAlveolar space (BAL) 9.0e6 5.6e6 15 85 3.4e6 15 85 6.0e7
Epithelium 2.4e10 7.2e9 15 85 1.7e10 15 85 2.0e8
Interstitium 5.0e9 2.5e9 15 85 2.5e9 15 85 0.0
Skin 7.2e8 3.6e8     3.6e8     0.0
Liver 9.6e8 4.0e8 31 69 5.6e8     0.0
Thymus 5.1e10 2.3e10 0 100 2.3e10     4.5e9
Misc Tissue 2.0e10 1.0e10     1.0e10     0.0
Total Body 1.2e12             1.7e10

Notes:

  • miscellaneous:
    1. See bCells pools worksheet
    2. Th: percentages between Naive and Memory adapted from Swain1996
  • Pool:
    1. MiscTissue: Percentages between Th (50%), Tc (50%) are place holders for now
    2. Lymph efferent: Farstad1997
Leukocyte Pools Worksheet 
Pool Macrophage Neutrophil Dendritic cells Eos Baso Mast cells NK
Blood 0 4200/ul 0 203/ul 7/ul 0.6/ul 0
Lymph Fluid efferent 0   0       2.5e8
afferent     5-15e4/ml       1.9e9
Peritoneal Cavity             0
Spleen 4.6e10           0
Lymph Nodes 2.5e9   2.2e10       3.8e8
Bone Marrow 0           1.0e8
Small Intestine total 2.8e10 9.3e8         0
Epithelium             0
Lamina propria             0
Peyer’s patches             7.5e8
Lung total 2.3e10   2.3e8       0
BronchoAlveolar space (BAL) 7.7e7 1.3e6   6.2e5   2.7e4  
Epithelium 2.3e10   2.3e8 6.0e6   1.0e7 2.5e9
Interstitium 8.0e7 1.6e8   2.4e8   4.0e8 5.0e8
Skin     1.0e9       4.0e7
Liver 1.0e11           4.8e8
Thymus             0
Misc Tissue       ~2.0e11     0
Total Body             1.7e10

Notes:
Pool:

  • Blood:
    • mast cells: Metcalfe1997
    • Monocytes: not listed, blood only
  • Lymph Fluid:
    • Dendritic cells: Fossum1989
  • Spleen:
    • macrophage: VanFurth1989, rough estimate
    • platelets: 30% of total
    • number of germinal centers = ((initialStrain * 5%) * 4096 / 3%) / 15,000
    • very rough estimate: fdc = 5.6e6 total, estimate: ~75k follicles total
  • lymphNode:
    • Marchuk1991
    • very rough estimate: fdc = 1.5e5/gram, estimate: follicles = ~2000/gram
  • Small Intestine:
    • macrophage: VanFurth1989, rough estimate
    • neutrophil: Pabst1987
  • Lung:
    • macrophage total: Crapo1982
    • dendritic total: xia1995: < 1%, (but Holt1994: 500-800dc/mm2 * 8e7mm2 = 4.8e10)
    • interstitium: Jeffery1989: neutrophil, eosinophils, mast
    • epithelium: Djukanovic1990, Pesci1993, Laitinen1993: eosinophils
    • BAL: Velluti1984: macrophage
    • BAL: Liu1991b: neutrophil, eosinophils, mast
    • BAL: iga: .9mg/ml, igg: .17mg/ml, ige: 77.2ng/ml, Reynolds_1976
  • skin:
    • dendritic: Banchereau1998
  • Liver:
    • macrophage: VanFurth1989, also from web: 1600grams * 1.0e7 kupfer/gram
  • miscellaneous tissue:
    • Eos: Weller1991
Migration Patterns Worksheet 
Destination Source
Lymphoblasts Non-Blasts
Lymph Node Spleen Lungs Gut skin
Bone Marrow 27 20 20     30
Muscle 10 25 8     3
Skin 12 10 5     1
Lungs 8 8 20     10
Liver 8 8 15     30
Gut 15 15 20     2
Lymph Nodes 4 3 5     10
Spleen 2 2 2     8
Misc 14 9 5     6
Total 100% 100% 100%     100%

Notes:

  • miscellaneous:
    • adapted from Binns1992
Lymphocyte Homing
homing receptor vascular addressin destination
L-selectin (cd62L) cd34, glyCAM-1 naive => lymphNode
L-selectin (cd62L) MAdCAM naive => peyersPatches
alpha4Beta7 MAdCAM naive => peyersPatches
memory/effector => Lamina Propria of GI tract
CLA E-selectin memory/effector => skin
VLA-4 VCAM-1 lymphoblasts => inflammation site
memory/effector => inflammation site
cd44 hyaluronate lymphoblasts => inflammation site

Notes:

  1. References: Farber2000, Springer1994, Stites p.61
T-Cell Surface Markers
Marker Naive effector Central Memory Memory
cd45ro - + + +
cd45ra high high low low
cd29 low high high high
cd25 (il2r) low high low low
cd28 high      
cd2 low     high
cd44 low     high

Notes:

  1. References: Farber2000, Springer1994, Lanzavecchia2000
  2. cd5, cd3+, cd4, cd8
Cells Table Worksheet
Cell name Diameter Half Life Rate Default Concentration Reference
RBC 7.8um life span = ~120days 1.6e11/day 5.0e6 cells/ul blood Guyton P.425
platelets 2-3um life span = 8-12 days 30k/day/mm3, 1.62e11/day 250e3 cells/ul blood Guyton P.435, 436, 463
neutrophils 10-15um circulation: 12 hours, tissue: 2 days ~1.0e9/kg-day = ~7.0e10/day 4200 cells/ul blood Guyton P.435, Stites p.32, storage in boneMarrow = 5x blood, eats 5 to 20 bacteria before dies; Benestad1989: migration to inflamed tissue (skin .5cm2) = ~2e6/hr
eosinophils 15-20um 30min circulation, 12days tissue   203 cells/ul blood Guyton P.435; for each in circulation: 500 in connective tissue, 200 in bone marrow
basophils       7 cells/ul blood Guyton P.435
monocytes 12-15um 10-12 hours in blood   42 cells/ul blood Guyton P.435, 436
bCells 5-12um     620 cells/ul blood Janeway P.67, 214, Westermann1992, Stites p.43
helper tCells 5-12um     1278 cells/ul blood Janeway P.67, Stites P.49,43, Westermann1992
cytotoxic tCells 5-12um     620 cells/ul blood Janeway P.67, Stites P.49, 43, Westermann1992
Dendritic cells   ~3 days   ? cells/ul Ruedl2,000
Mast cells 10-15um     ? cells/ul  
Macrophage 20-50um     ? cells/ul Guyton 439: eats ~100 bacteria before dies
NK cells       ? cells/ul  
Cytokines Table Worksheet 
Cytokine Molecular Weight Half Life Rate Default Conc. Cells Reference
gcsf 18k         Benestad1989
gmcsf 19k-90k, 22k Benestad1989 HL = 5 min. blood, HL = 1-3 hours tissue   1ng/ml blood macrophage, tCells Petros1992
il-1 17000 HL < 1hr     macrophage Mondino1996; Stites; inflammatory
il-2 15400 HL < 1hr     activated Th1 produces, co-stimulus for tCell expansion, autocrine, paracrine Stites
il-3 18k 35 min     Mast, eos growth Benestad1989, Khwaja1994
il-4 15000 HL < 1hr       Stites; immunosuppressive
il-5 30,000 HL < 1hr     Th2 produces, eosinophil growth Portanova1995
il-6 22000 – 30000 HL < 1hr       Stites; inflammatory
il-10 18000 HL < 1hr     Th2, CD8+, macrophage, monocytes, dendritic, bCells, eosinohil, mast cells… Mondino1996; Stites; immunosuppressive
il-12 35000 – 40000 HL < 1hr     macrophage, dendriticMature Lanzavecchia2000; Stites
il-15   HL < 1hr        
il-18   HL < 1hr     dendriticMature Lanzavecchia2000
ifn-alpha 16000 – 27500, 17k HL = 42min     dendriticMature Lanzavecchia2000; Stites; type1; (note: 8e-5iu = 6e3 molecules, conversion factor = 7.5e7)
ifn-gamma 18000 HL < 1hr     Th1 produces, activates macrophage, iG class switching (igG2a in mouse, igG2a: fix complement, macrophage Fc receptors), cd8 Stites; type2
mif   HL < 1hr     activates macrophages macrophage inhibition factor
tnf-alpha ~20k HL < 1hr     macrophage Mondino1996; inflammatory
tgf-beta   HL < 1hr       Mondino1996; immunosuppressive

Notes:

  • miscellaneous:
    • References: Janeway p.588; Stites p.16, ch 10
Plasma and Extracellular Fluid pools:
Extracellular Fluid triglycerides
(grams)
fatty acids
(grams)
glucose
(grams)
protein
(grams)
Blood plasma 3, note c .3-.45, note d 2.7, note b 219, note e
Interstitial fluid     10.0, note b 280, note e

Notes:

  • Stryer P. 771, Voet P.792
  • in lipoproteins,Voet P. 792
  • free fatty acids, Guyton P. 866, Voet P.792
  • 7.3grams/dl * 3liters = 219grams, 2.5g/dl interstitial, Guyton P.190, Voet P.375

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Books/Monographs

  • Berne, Levy – Physiology, 4th ed
  • Brooks – Exercise Physiology, 3rd ed
  • Greenspan – Basic and Clinical Endocrinology 5th ed
  • Greger – Comprehensive Human Physiology (vol I,II), 1996
  • Guyton and Hall – Textbook of medical physiology, 9th ed
  • Janeway – Immunobiology 4th ed, 1999
  • Lehninger – Principles of Biochemistry, 2nd ed
  • Mims – Medical Microbiology 2nd ed, 1998
  • Rose – The Autoimmune Diseases 3rd ed, 1998
  • Salway – Metabolism at a Glance, 1994
  • Shargel – Applied biopharmaceutics and pharmacokinetics, fourth ed
  • Stites – Medical Immunology 9th ed, 1993
  • Stryer – Biochemistry, 4th ed
  • Vander – Human physiology, 7th ed
  • Voet & Voet – Biochemistry, 2nd ed
  • Abramson – blood vessels and lymphatics in organ systems (flow data for organs)
  • Alberts – Molecular Biology of the Cell, 3rd ed
  • Berne P.,Levy – Cardiovascular physiology
  • Fung – Biomechanics, circulation
  • Johnson – Gastrointestinal Physiology
  • Netter – Atlas of human anatomy
  • Segel – Enzyme Kinetics, 1993

Web Sites

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