TGFB1 and influenza: However, blocking TGFβ signaling in vivo, using either anti-TGFβ blocking antibody or the TGFβRII CD4+ T cell conditional-dominant negative (DN) mouse model (dnTGFβRII), did not alter the frequency of Tfh in models of NP-KLH immunization and influenza infection (35, 41, 68).