CD4 and infection: Although HIV preintegration transcription is limited to early genes in resting CD4 T cells [14], culturing resting T cells with common gamma-chain cytokines, including IL-2, IL-,4, IL-7 and IL-15 relieved this restriction and permitted HIV-1 replication in the absence of integration [95]; in these cytokine-treated and post infection-activated T cells, mutating the HIV integrase active sites (D116N, D64E) or using an integrase inhibitor, raltegravir, did not block HIV-1 replication, although both effectively blocked viral integration.