PAM3- and M-CSF–stimulated monocytes suppress T-cell proliferation and alter the generation of Th1 vs Th2 cells. Autologous T cells stimulated with anti-CD3/CD28 were added to purified monocytes activated as described in Figure 2. (A) T-cell proliferation was monitored by carboxyfluorescein diacetate succinimidyl ester dilution on day 5 (mean ± standard deviation of 4-5 independently studied donors). Percentage of CD25⁺ T cells (B) and IL-4– vs IFN-γ–expressing T-cell ratio (C) on day 7 (mean ± standard error of the mean of 4-5 independently studied donors). *P < .05, **P < .01, ***P < .001 vs stimulated T cells plus monocytes; +P < .05 PAM3 vs M-CSF cultures.