The effects of blocking endogenous activin-A with follistatin on CD40L-mediated IL-12, TNF-α, and chemokine production by MoDCs. Immature MoDCs were cultured in 96-well plates for 24 hours with either GM-CSF and IL-4 alone or with CD40L in the absence or presence of increasing concentrations of follistatin, and supernatants were collected after 24 hours and assayed by ELISA for IL-12p70 (A) or TNF-α (B) or assayed for IL-8 (C), IP-10 (D), RANTES (E), and MCP-1 (F) production using a Cytometric Bead Array system. Data represent the mean plus or minus 1 SD of 3 separate donors. *P ≤ .01, **P ≤ .05 versus CD40L only.