PDCD1 and HIV-1 infection: PD-1–PD-L2 interactions have recently been shown to affect the survival and maintenance of PCs in mice through a mechanism regulated by PD-1 expression on Tfh cells and PD-L2 expression on B cells.30 The molecular pathway leading to expression of PD-Ls on activated B cells remain poorly characterized and it is unknown whether this pathway is affected during HIV-1 infection.