Neutrophil recruitment into the peritoneal cavities of TNF-α knockout, mast cell-deficient, and FcγRIII knockout mice 8 h after injection of hIgG and SpA. The number of neutrophils was markedly reduced in TNF-α knockout versus wild-type mice (n = 6 in each group, mean ± standard deviation, P < 0.0008), mast cell-deficient versus wild-type mice (n = 9 in each group, mean ± standard deviation, P < 0.0007) and mast cell-deficient versus mast cell-reconstituted mice (n = 9, mean ± standard deviation, P < 0.0001), and in FcγRIII knockout mice versus wild-type mice (n = 10 in each group, mean ± standard deviation, P < 0.007).