Survival of human platelets in NOD/SCID mice. Human PRP (200 μL) at 2 × 109 platelets/mL was injected into the retro-orbital plexus of NOD/SCID mice, and human platelet survival was measured by flow cytometry using AP2 (a monoclonal antibody specific for the human GPIIb-IIIa complex). (A) Flow cytometric data showing a typical time course of human platelet survival following intraperitoneal injection of an isotype-matched control mAb. Note that approximately 50% of the human platelets are lost from circulation over a period of 24 hours, most likely reflecting the kinetics of normal clearance resulting from platelet aging. (B) Comparison of human platelet survival over time in mice treated with an isotype-matched intact monoclonal IgG, the GPVI-specific mAb 11A12, or the anti–PECAM-1 mAb PECAM 1.3. (C) Human platelet survival in the mouse circulation following exposure to 30 μg Fab fragments of the GPVI-specific mAb 6B12 or PECAM 1.3. Note that the rate of platelet clearance (∼ 40% in 24 hours) is not significantly greater than observed in mice treated with nonbinding isotype-matched mAbs shown in Figure 1B. Data shown is representative of 5 (A,B) and 7 (C) separate experiments.
