As a result, there were fewer Tfh and more Th1 cells in the absence of the TGF-β receptor after viral infection.125 Human naive T cells cultured in the presence of TGF-β demonstrated increased expression of Tfh-related genes, including BCL6 and CXCR5, and decreased expression of Blimp-1.124 TGF-β signals through STAT3 to drive the differentiation of human Tfh cells;124 however, this has not been established in mice. Here, STAT3 is linked to viral infectious disease.