A novel antiplatelet antibody therapy that induces cAMP-dependent endocytosis of the GPVI/Fc receptor γ-chain complex
J. Clin. Invest. Hiroshi Takayama, et al. 118:1785 doi:10.1172/JCI32513 [Go to this article.]

Figure 2
mF1201, but not mF1232, induces both platelet aggregation and shedding of surface GPVI, while mF1232 inhibits collagen-induced, but not CRP- or ADP-induced, platelet aggregation. (A) Platelet aggregation was monitored after the addition of the indicated concentrations of mF1201 or mF1232 into human PRP. (B) After human PRP was incubated without (none) or with the indicated concentrations of CRP, mF1232, mF1201, or mIgG for 30 minutes at 37°C, the platelets were fixed and stained with PE-labeled anti-human CD62P Ab for flow cytometry analysis. Data represent mean ± SEM of triplicate determinations. MFI, mean fluorescence intensity. (C) Human PRP was preincubated with the indicated concentrations of mF1232 for 5 minutes at 37°C and stimulated with 1 μg/ml collagen, 4 μg/ml CRP, or 5 μM ADP as indicated by arrows. Traces are representatives of 2 or 3 separate experiments from different donors. (D) Washed human platelets were treated without (control) or with 0.15 μg/ml convulxin (Cvx), 10 μg/ml mF1232, or 10 μg/ml mF1201 for 60 minutes at 37°C, and centrifuged to isolate platelet pellets from supernatants. Platelet pellets (cell lysate) and supernatants were analyzed by western blotting using rabbit anti-GPVI polyclonal Abs. Data are representatives of 3 separate experiments from different donors.