Characterization of human platelet binding of recombinant T cell receptor ligand

Table 1 Effects of inhibitors and antagonists on platelet surface area

	Platelet adhesion (cells/mm² × 10²)		Surface area (μm²)
Inhibitor/antagonists	RTL1000	fibrinogen	RTL1000	fibrinogen
vehicle	44.9 ± 1.1	52.8 ± 1.6	35.5 ± 3.1	31.8 ± 1.2
ADP-scavenger/cyclooxygenase inhibitor	33.4 ± 0.5	34.3 ± 0.7	34.5 ± 3.9	32.1 ± 2.2
α_IIbβ₃ antagonist	26.4 ± 0.8	7.9 ± 1.5	17.6 ± 1.8	16.7 ± 2.3
Src kinase inhibitor	26.4 ± 0.8	48.4 ± 1.9	23.7 ± 2.0	20.0 ± 1.5
Syk kinase inhibitor	36.1 ± 0.5	44.0 ± 0.4	19.5 ± 1.9	25.0 ± 1.4
PI3 kinase inhibitor	29.0 ± 0.5	30.8 ± 0.9	26.3 ± 1.7	17.3 ± 1.4
protein kinase C inhibitor	36.7 ± 0.5	53.7 ± 1.7	19.4 ± 2.3	27.3 ± 1.6
intracellular Ca²⁺ chelator	11.4 ± 1.1	13.2 ± 1.2	15.5 ± 2.1	17.2 ± 1.4

Purified human platelets (2 × 10⁷/ml) were placed on RTL1000- or fibrinogen-coated coverslips for 45 min at 37°C with an ADP-scavenger and cyclooxygenase inhibitor (apyrase/indometacin, 2 U/ml/10 μM), the α_IIbβ₃ receptor antagonist (eptifibatide, 20 μg/ml), inhibitors to Src kinases (PP2, 20 μM), Syk kinase (BAY 61-3606, 20 μM), PI3 kinase (wortmannin, 100 nM), protein kinase C (R0 31-8220, 20 μM) or an intracellular Ca²⁺ chelator (BAPTA-AM, 10 μM). Values are reported as mean ± SEM of 50-300 cells

ISSN: 1742-2094