Table 4. Parameter values for the leukocyte membrane and ligands along with corresponding wet-lab values.
Parameter Name | Description | Model Parameter Value | Experimental Value | Reference |
LeukTotalWidth | Leukocyte membrane width (in the y [east-west] dimension) | 20 membrane units | Average murine Neutrophil Diameter: ∼7 µm | [59] |
LeukTotalLength | Leukocyte membrane length (in the x [north-south] dimension) | 30 membrane units | Average murine Neutrophil Diameter: ∼7 µm | [59] |
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 |
LFA1GridSize ICAM1GridSize | Length/width of lfa1Grid and icam1Grid | 100×100 | NA | NA |
LFA1GridDensity | Density of lfa1Grid on membrane exposed to the surface. | 0.20 | NA | NA |
NumLFA1Clusters | Number of lfa1 clusters/lfa1Grid formed if clustering is initiated | 2 | N/A | N/A |
LFA1ClusterDiameter | The length and width of the lfa1 cluster on the lfa1Grid | 6 | N/A | N/A |
PSGL1Density | Mean number of PSGL-1 molecules (± standard deviation) represented by each psgl1 agent | 120±5 | ∼75,000/murine neutrophila | [60] |
LFA1Density | Mean number of LFA-1 molecules (± standard deviation) in each membrane unit | 25±5 | ∼50,000/murine neutrophila | [61] |
LFA1RemovalRate | Probability that an unbound lfa1 will be removed from the membrane | 0.0025 | NA | [31],[32] |
CXCR2Density | Number of CXCR-2 molecules (± standard deviation) represented by each cxcr2 agent | 1 | NA | NA |
Pon (psgl1-pselectin) | Probability of forming a psgl1-pselectin bond | 0.001 | NAb | [62] |
Pon (low affinity lfa1-icam) | Probability of forming a low affinity lfa1-icam1 bond | 0.01 | NAb | [63] |
Pon (high affinity lfa1-icam1) | Probability of forming a high affinity lfa1-icam1 bond | 1.0 | NAb | [64],[65] |
Pon (cxcr2-cxcl1) | Probability of cxcr2 interacting with cxcl1 | 1.0 | NA | NA |
Poff (cxcr2-cxcl1) | Probability of cxcr2 releasing cxcl1 | 1.0 | NA | NA |
Neutrophils were incubated with fluorescence-conjugated mAbs to LFA-1 or PSGL-1 and analyzed by FACScan flow cytometry. LFA-1 receptor number was quantified by comparing the binding of neutrophils to LFA-1-FITC with the binding of receptor-coated microbeads with known binding site densities [61]. PSGL-1 receptor number was determined in a similar fashion [60].
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.