FcγRI mediates LTB4/BLT1 enhancement of IgG-RBC phagocytosis. (A) AMs from wild-type and BLT1 KO mice were pretreated with LTB4 (1 and 100 nM) or LTD4 (100 nM) for 5 minutes before challenge with 50:1 IgG-RBCs. Phagocytosis was determined, as described in “Phagocytosis and bacterial killing,” and expressed as the mean ± SEM from 3 independent experiments, each performed in quintuplicate. *P < .05 compared with control wild type, and #P < .05 compared with BLT1 KO. (B) Rat AMs were pretreated for 30 minutes with vehicle control or 1 μg/mL anti-FcγRI, anti-FcγRII, or anti-FcγRIII, followed by a 5-minute incubation with or without 10 nM LTB4. They were then incubated with IgG-RBCs (50:1), and phagocytosis was determined, as described in “Methods,” and expressed as the mean ± SEM from 3 independent experiments, each performed in quintuplicate. *P < .05 compared with control; #P < .001 vs LTB4-treated cells.
