Table 4.
Model parameter values for the LEUKOCYTE MEMBRANE and LIGANDS along with corresponding in vitro values
| Parameter Name | Description | Model Parameter Value | Experimental Value | Reference | |
| LeukTotalWidth | LEUKOCYTE MEMBRANE width (in the y [east-west] dimension) | 20 MEMBRANE UNITS | Avg. Human Leukocyte Diameters (μm): Lymphocyte: 6.2; Neutrophil: 7; Monocyte: 7.5 | [48] | |
| LeukTotalLength | LEUKOCYTE MEMBRANE length (in the x [north-south] dimension) | 30 MEMBRANE UNITS | |||
| LeukExposedWidth | CONTACT ZONE width (in the y dimension) | 8 MEMBRANE UNITS | NA | NA | |
| LeukExposedLength | CONTACT ZONE length (in the x dimension) | 10 MEMBRANE UNITS | NA | NA | |
| PSGL1DensityMean ± PSGL1DensitySTDev | Mean number of PSGL-1 molecules (± SD) represented by each PSGL1 agent | Experiment 1: Neutrophils | 150 ± 5a molecules | ~18,000/Human Neutrophil | [54] |
| Experiment 3: Monocytes | 150 ± 5b molecules | N/A | N/A | ||
| VLA4DensityMean ± VLA4DensitySTDev | Mean number of VLA-4 molecules (± SD) represented by each VLA4 agent | Experiment 2: T-lymphocytes | 45 ± 5 molecules | 3,000/Human T-Lymphocyte | [55] |
| Experiment 3: Monocytes | 60 ± 5 molecules | 6,000/Human Monocyte | |||
| CXCR2DensityMean ± CXCR2DensitySTDev | Number of CXCR-2 molecules (± standard deviation) represented by each CXCR2 agent | 1 ± 0 molecules | NA | NA | |
| VLA4MaxPercHighAff | Maximum percent of VLA-4 integrins on the leukocyte membrane that can be induced into a high affinity statec | 12.5% | 10% | [49] | |
| Pon (PSGL1-PSELECTIN1) | Probability of forming a PSGL1-PSELECTIN1 BOND | 0.001 | NAd | [56] | |
| Pon (LOW AFFINITY VLA4-VCAM1) | Probability of forming a LOW AFFINITY VLA4-VCAM1 BOND | 0.001 | NAd | [55] | |
| Pon (HIGH AFFINITY VLA4-VCAM1) | Probability of forming a HIGH AFFINITY VLA4-VCAM1 BOND | 0.005 | NAd | [55] | |
| Pon (CXCR2-GROA) | Probability of forming a CXCR2-GROA BOND | 1.0c | NA | NA | |
| Poff (CXCR2-GROA) | Probability of breaking a CXCR2-GROA BOND | 1.0c | NA | NA | |
a PSGL1DensityMean ± PSGL1DensitySTDev parameter values used for simulating Experiment 1, neutrophil rolling, were originally 25 ± 5. They were changed to the values currently listed to more closely reflect the experimental values of PSGL-1 density reported in the literature. No significant differences were observed when using these new parameter values.
b Values for PSGL-1 sites/human monocyte were not found in the literature and were assumed to be similar to values reported for human neutrophils.
c See Methods.
d Pon and Kon are intended to map to aspects of the same in vitro phenomena. However, there is no direct mapping between these parameters because the parent models belong to fundamentally different classes [57].