Effect of coligation of LIR3 with LIR7 or FcϵRI on activation of human basophils. PBMCs (A-D) or purified basophils (E) were treated with IL-3 and then incubated with 0.1 μg/mL anti-LIR7 (A, C, and E), anti-FcϵRI (B, D, and E), or control IgG₁ (A-E), in the presence of increasing concentrations of anti-LIR3 or 10 μg/mL IgG₁ control antibody. Basophils were then activated by the addition of 10 μg/mL goat anti-mouse IgG for 45 minutes (A-D) or 4 hours (E). Supernatants were assayed for histamine (A-B), cysteinyl leukotrienes (C-D), or IL-4 (E) by EIA.