WNT5A- and FZD5-dependent regulation of Th1 cytokine responses. (A) PBMCs of PPD-reactive donors were stimulated with PPD (10 μg/mL) in the presence of anti-Wnt5a or isotype-matched control antibodies. IFN-γ (96 hours) and IL-2 (24 hours) concentrations in supernatants were analyzed by ELISA. Stimulation was performed in triplicates: mean ± SD of 1 of 3 independent experiments are depicted. (B) PPD- or M avium–induced (10 μg/mL and MOI 3, respectively) IFN-γ and IL-12p40 release by PBMCs in the presence of optimal inhibitory anti-WNT5A antibody concentration (10 μg/mL) was determined. Three independent experiments using cells of individual donors were compared by normalizing control conditions (cultures treated with goat-IgG) to 100%. (C) PBMCs of PPD-reactive donors were stimulated with PPD (10 μg/mL) in the presence of an anti-FZD5 antiserum and preimmune serum. IFN-γ (96 hours) and IL-2 (24 hours) concentration in supernatants were analyzed by ELISA. Experiments were performed in triplicate; mean ± SD of 1 of 3 independent experiments are depicted. (D) PPD- or M avium–induced (10 μg/mL and MOI 3, respectively) IFN-γ and IL-12p40 release by PBMCs in the presence of optimal inhibitory dilution of the anti-FZD5 antiserum (1/100) were determined. Three independent experiments using cells of individual donors were compared by normalizing control conditions (cultures treated with preimmune serum) to 100% (*P < .05; **P < .01; ***P < .001).