Up-regulation in Th17 immune response by T-bet^−/− LN cell infusion. In 2 experiments, we measured plasma cytokine concentrations by enzyme-linked immunoassay as detailed in methods. Infusion of B6 LN cells (n = 6) resulted in greater (P < .05) plasma IFN-γ (A) concentration in comparison with TBI-only control mice. In contrast, infusion of T-bet^−/− LN cells (n = 6) resulted in greater plasma TGF-β (P < .01, B) and IL17A (P > .05, B) concentrations relative to TBI-only control mice (n = 3).