Opsonization of bacteria modulates cytokine production by human DCs. (A-B) DCs were stimulated for 24 hours with S aureus that was preincubated or not in (A) human serum (HS) or (B) purified IgG. Cytokine levels were determined in the supernatant by ELISA. Data shown are from 1 representative experiment of 6 experiments with different donors. (C) Monocytes were stimulated as described under panel B, after which cytokine levels in the supernatant were determined by ELISA. Data shown are from 1 representative experiment of 3 experiments with different donors. Error bars indicate SEM; *P < .05, **P < .01; ns indicates not significant; paired t test.