Figure 2.

Vav exchange activity is required for FcγR- but not CR3-mediated phagocytosis. The effect of expressing different Vav or GTPase constructs on the attachment (right) and phagocytosis (left) of IgG- or C3bi-opsonized RBC was analyzed. Results are shown relative to expression of a control vector (−). Dominant negative Vav constructs (Vav-C and VavΔDH) but not full-length Vav (pVav) inhibited FcγR-mediated phagocytosis in J774.A1 macrophages (A) and receptor-transfected COS cells (B) to levels comparable to blocking Rac (N17Rac) or Cdc42 (N17Cdc42) function. In contrast, dominant negative Vav had no effect on CR3 phagocytosis in J774 macrophages (C). Data shown are the mean ± SEM of at least three independent experiments.