FIG 1.

Monocyte responses to PGN are not influenced by IgG titer. (A) Sera from 8 individual donors were analyzed for IgG titers as described in Materials and Methods. From these data we identified 2 high-titer donors (open shapes) and 2 low-titer donors (black-filled shapes). Data shown represent means ± standard errors of the means (SEM) from sera tested in quintuplicate at each concentration. (B) Paired PBMCs were stimulated with PGN in the presence of serum from either the high- or low-titer donors. Monocyte responses to PGN were assayed by intracellular staining for TNF-α. Titration curve was conducted in quintuplicate. Data shown represent means ± standard deviations (SD) from 3 separate donors. Unless connected by a line, significance shown is that compared to cells stimulated with PGN in the presence of FCS only. *, P < 0.05; **, P < 0.01; ***, P < 0.001; n.s., not significant. Two-way ANOVA with Bonferroni posttest was used.