Fig. 6.

FcγR-mediated uptake of IgG-opsonized Schu S4 restricts intracellular proliferation through NADPH oxidase-dependent ROS production. (A) ROS production by either C57BL/6, FcRγ-KO, or gp91^Phox-KO BMMs that were left untreated or were pretreated with E. coli LPS for 24 h and stimulated with PMA (LPS+PMA). Cells were placed in luminol-containing KRG buffer, and luminescence (cps) was measured over a 60-min period. Data are means ± standard deviations from triplicate samples of a representative experiment out of three. (B) ROS production by either C57BL/6, FcRγ-KO, or gp91^Phox-KO BMMs after 5 min of phagocytosis of PFA-killed IgG-opsonized Schu S4. Data are means ± standard deviations from triplicate samples of a representative experiment out of three. (C to E) ROS production by either C57BL/6 (C), FcRγ-KO (D), or gp91^Phox-KO (E) BMMs after 5 min of infection with either unopsonized (control), serum-opsonized (serum), or IgG-opsonized (IgG) live Schu S4. Data are means ± standard deviations from triplicate samples of a representative experiment out of three. (F) BMMs from gp91^Phox-KO mice were infected with either unopsonized (control), serum-opsonized (serum), or IgG-opsonized (IgG) Schu S4, and intracellular CFU were enumerated at 1 and 12 h p.i. Replication index was calculated as fold change in intracellular CFU between 1 and 12 h p.i. Values are means ± standard deviations of three independent experiments.