Inhibition of platelet collagen binding by JAQ1 and LEN/B. (A) Monoclonal anti-GPVI antibody (JAQ1) was injected intraperitoneally, and GPVI level was monitored by flow cytometric analysis. Platelets were detected by FITC-labeled anti-GPVI antibody (n = 6). The percentage of GPVI-positive platelets was significantly (P < .001) reduced following JAQ1 treatment after 3 days of injections. (B) Flow cytometric analysis of LEN/B-FITC binding to platelets from untreated mice (control), mice which received 100 µg of LEN/B, or mice lacking α2β1 (Itga2^−/−).²  Results are MFI ± standard deviation of 4 mice per group. The inhibition of α2β1 by LEN/B was significant and comparable to Itga2^−/−. (C) Washed platelets were incubated 10 minutes at 37°C with control IgG (control) or the indicated antibodies and subsequently stimulated with collagen. Light transmission was recorded on a Born aggregometer. Representative aggregation curves of 2 individual experiments (n = 4 each) are depicted. Delayed response in LEN/B-treated platelets and decreased response in JAQ1-treated platelets were observed. Aggregation was abolished with the inhibition of both. MFI, mean fluorescence intensity; N.S, not significant; ***P < .001.