Description: The eBio39D monoclonal antibody reacts with mouse, rat and human T-bet. T-bet is a Th1-specific T-box transcription factor critical to the development of the Th1 CD4+ T cell lineage. This is known based on the observations that T-Bet deficient mice have impaired Th1 cell development, and that ectopic expression of T-Bet results in development skewed to the Th1 lineage. T-Bet expression is induced by the Th1 cytokine IFN-γ, and T-Bet also regulates the expression of IFN-γ, likely, at least in part, through the modification of DNA accessibility and histone remodeling. In addition to IFN-γ, T-Bet is also known to regulate the expression of IL-12Rβ and IL-2. Moreover, T-Bet plays a role in class-switch recombination in B-cells.