CD4 and infection: Like the origins of latent infections by direct infection of resting CD4+ T cells, we speculate that the permissiveness of ostensibly resting T cells to direct infection and establishment of both productive and latent infections is related to the LT environment of cell-cell contact and interactions and secreted cytokines and factors (35–38), as has been described in cell culture models of direct establishment of latent infections in resting T cells.