CD4 and infection: Numerous studies identified several cell populations with high susceptibility to infection, including central memory CD4+ T cells (TCM) (Chomont et al., 2009; Jaafoura et al., 2014; Boritz et al., 2016), CD4+ T memory stem (TSCM) cells (Buzon et al., 2014), regulatory T (TREG) cells (Oswald-Richter et al., 2004; Tran et al., 2008; Moreno-Fernandez et al., 2009; McGary et al., 2017); TH17 cells (Gosselin et al., 2010, 2017), T follicular helper cells (TFH) (Perreau et al., 2013; Banga et al., 2016).