CD4 and infection: DNT cells seem essential in compensating CD4 T-cell depletion as they are associated to the nonpathogenic nature of the infection in SIV-infected natural hosts.[15] Natural hosts, such as sooty mangabeys and African green monkeys, do not develop AIDS and are able to maintain preserved T-cell populations and low levels of systemic immune activation despite high levels of virus replication.[16,17] These primates exhibit up to 40% of DNT cells that are capable of proliferating and producing T helper cytokines following antigen stimulation.[6,15]