FIG. 5.

Dependence of SpA-hIgG-induced peritoneal Arthus reaction on complement. The 8-h SpA-induced peritoneal Arthus reaction was reduced 90% in C3-deficient versus wild-type mice (n = 8 in each group, mean ± standard deviation, P < 0.04) and 60% in C5-deficient versus wild-type mice (n = 4 in each group, mean ± standard deviation, P < 0.004). BALB/c mice treated with a C5aR inhibitor (50 μg) demonstrated a 64% reduction in the number of neutrophils in the peritoneal cavity 8 h after injection of hIgG and SpA compared to those treated with saline (n = 10 in each group, mean ± standard deviation, P < 0.001).