CD4 and infection: The latent reservoir is established early during infection [5, 6] and latent proviruses can be found, albeit at different frequency, in all CD4+ T cell subsets including naive (TNA), stem cell memory (TSCM), central memory (TCM), effector memory (TEM), and terminally differentiated (TTD) T cells [7–10] as well as in monocyte and macrophages [11–13].