ERK activation is critical for CARD9-mediated innate immunity against C. albicans. (A and B) WT and CARD9-deficient mice were intravenously injected with 5 × 10⁴ CFU of mnn5. Infected mice were treated with or without U0126 (50 µg per mouse) at days 0, 2, 4, and 6 after infection. Survival of infected mice (n = 10 per group) was monitored (A) and kidney CFU assay (n = 5 per group) was performed at day 2 after infection (B). *, P < 0.05; **, P < 0.01. (C) ELISA results of TNF, IL-1β, IL-6, IL-12p40, IL-17A, IL-10, and IL-23 in the extracts of homogenized kidneys from WT and CARD9-deficient mice 4 d after infection with 5 × 10⁴ CFU of mnn5. Infected mice were treated with or without 50 µg U0126 per mouse at days 0 and 2 after infection. *, P < 0.05; **, P < 0.01; ***, P < 0.001, n = 5 per group. Data shown are representative of three independent experiments. SDs are indicated.