(A) Native Pneumocystis carinii (Pc) major surface glycoprotein (Msg) significantly dampens production of tumor necrosis factor (TNF)-α in vitro in the presence of Pc β-glucan or with (B) Saccharomyces cerevisiae (Sc) β-glucan. RAW 264.7 macrophages (2 × 10⁵) were incubated with or without Pc Msg and in the presence of absence of β-glucans (150 µ g/mL) for 24 hours. Supernatants were collected, and secreted TNF-α was analyzed. Data are the ±standard error of the mean for 4–5 biological replicates per group. **, P < .01 and ****, P < .0001.