Figure 3. Platelets from Pf4-Cre⁺-Crry^flox/flox mice were resistant to complement attack.

(A) Peripheral platelet count in Pf4-Cre⁺-Crry^flox/flox mice was normal (n= 17–20 mice per group). Error bars represent SEM. (B) FACS analysis showing no C3 deposition on Pf4-Cre⁺-Crry^flox/flox mouse platelets in vivo. (C) ELISA assay showing normal plasma intact C3 levels in Pf4-Cre⁺-Crry^flox/flox mice. Each data point represents a single mouse. Levels are normalized to a reference plasma sample from a randomly chosen WT mouse. (D) ELISA assay of LPS-induced AP complement activation showing normal complement activity in the sera (1: 10 dilution) of Pf4-Cre⁺-Crry^flox/flox mice (n= 6 mice per group). Error bars represent SEM. (E) FACS analysis showing that DAF^−/−/Crry^−/−/C3^−/− (TKO) mouse platelets were sensitive to AP complementmediated C3 deposition, while Pf4-Cre⁺-Crry^flox/flox platelets were resistant. (F) FACS analysis showing that platelets from Pf4-Cre⁺-Crry^Δ/Δ mice (on DAF^−/− background), which had secondary complement insufficiency, were also sensitive to AP complement-mediated C3 deposition. Results in E and F were representative of >3 independent experiments. TKO: DAF^−/−/Crry^−/−C3^−/−, Pf4-Cre−: Pf4-Cre⁻-Crry^flox/flox, Pf4-Cre+: Pf4-Cre⁺-Crry^flox/flox mice. N.S. p > 0.05, Student t test.