Effect of 5-LO gene knockout in FcγR-mediated Syk activation. (A) Alveolar macrophages harvested from WT and 5-LO KO mice were challenged with IgG-SRBC (1:100 ratio) and then incubated for 7 minutes at 37°C. (B) Peritoneal macrophages harvested from WT and 5-LO KO mice were challenged with IgG-SRBCs (1:33 and 1:100 ratio) and then incubated for 7 minutes at 37°C. Incubations were terminated by addition of lysis buffer, and lysates were subjected to immunoprecipitation and immunoblotting as described in “Materials and methods.” Data are given as means ± SEMs. *P < .05 compared with WT group (ANOVA followed by Bonferroni t test). Results are representative of 3 separate experiments.