Simian immunodeficiency virus (SIV) from sun-tailed monkeys (Cercopithecussolatus): Evidence for host-dependent evolution of SIV within the C. lhoesti superspecies

Recently we reported the characterization of simian immunodeficiency virus (SIVlhoest) from a central African l'hoest monkey (Cercopithecus lhoesti lh oesti) that revealed a distant relationship to SIV isolated from a mandrill (SIVmnd). The present report describes a novel SIV (SIVsun) isolated from a healthy, wild-caught sun-tailed monkey (Cercopithecus lhoesti solatus), a nother member of the l'hoest superspecies. SNsun replicated in a variety of human T-cell lines and in peripheral blood mononuclear cells of macaques ( Macaca spp.) and patas monkeys (Erythrocebus patas). A full-length infectio us clone of SIVsun was derived, and genetic analysis revealed that SIVsun w as most closely related to SIVlhoest, with an amino acid identity of 71% in Gag, 73% in Pol, and 67% in Env. This degree of similarity is reminiscent of that observed between SIVagm isolates from vervet, grivet, and tantalus species of African green monkeys. The close relationship between SNsun and SIVlhoest, despite their geographically distinct habitats, is consistent wi th evolution from a common ancestor, providing further evidence for the anc ient nature of the primate lentivirus family. In addition, this observation leads us to suggest that the SIVmnd lineage should be designated the SIVlh oest lineage.