Endogenously produced IL-10 suppresses OKT3-stimulated T-cell proliferation and inflammatory cytokine production in cocultures between G-PBMC-derived CD4 and CD14 cells. CD4 cells at fixed numbers (50 × 103) plus sorted CD14 cells at varying numbers were cultured in flat-bottom 96-well plates precoated with OKT3 antibody at a concentration of 50 ng/mL. (A) Proliferation was measured on day 4 by3H-thymidine incorporation in cultures with (dashed lines) or without (solid lines) neutralizing antibodies to IL-10. Values represent the mean ± SEM from triplicate cultures. (B through E) Concentrations of cytokines IL-10, IFN-γ, TNF-α, and IL-1α as indicated were determined at the time of the proliferation assay (day 4) by ELISA in cultures without (solid lines) or with (dashed lines) neutralizing antibodies to IL-10. Shown is the mean of duplicate ELISA determinations using pooled supernatants from triplicate cultures.
