At 60 h post-infection, the activated Smarta CD4+ T cells were mostly in the 4th and 5th divisions, a window in which nascent TH1 and TFH cells emerge5,8, with nascent TH1 expressing higher Blimp1-YFP and nascent TFH cells being Blimp1-YFPlo. The gene discussed is CD4; the disease is infection.