CD4 and infection: Interestingly, the survey of the kinetics of CD4+ T helper cell responses in blood demonstrated a Th1 (Tbet+CD27-) dominated immune response, and only a weak increase of Th2 (CD27-GATA3+) cells in the circulation at 2-4 weeks post-infection that resolved during chronicity (Figures 1C, D, Supplementary Figure 1A).