73 Identification of a Novel SIV Lineage with a Vpu Gene in Cercopithecus Monkeys from Cameroon Valerie Courgnaud1, Severin Loul2, Eitel Mpoudi2, Florian Liegeois1, Bernadette Abela2, Xavier Pourrut2, Eric Delaporte1, Beatrice Hahn3, Martine Peeters*1 1UR36, IRD and Univ of Montpellier, France; 2Projet Prevention du Sida au Cameroun (PRESICA), Yaounde, Cameroon; and 3Univ of Alabama at Birmingham
Background: Primate lentiviruses are a diverse group that naturally infect a variety of nonhuman African primate species. So far, 6 distinct lineages (SIVcpz, SIVsm, SIVagm, SIVsyk, SIVlhoest, and SIVcol) and potential recombinant lineages have been described. In order to elucidate origins and evolution in the primate lentivirus family, molecular characterization of additional SIVs in essential. During a large seroprevalence survey of wild-born monkeys in Cameroon, we identified SIV infected mona monkeys (SIVmon, Cercopithecus mona) and mustached guenons (SIVmus, Cercopithecus cephus).
Methods: The complete sequences of SIVmon-99CM-CML1 and SIVmus-01CM-1085 genome were obtained by long PCR methods. Viral sequences from uncultured PBMC DNA were amplified by targeting unintegrated circular DNA. The new sequences were compared to previously reported SIV sequences.
Results: Full-length genome sequence analysis revealed that SIVmon and SIVmus are closely related to the previously described SIVgsn from greater spot-nosed monkeys (Cercopithecus nicititans). They displayed the same genetic organization including the presence of a vpu gene, initially a unique feature of the members of the SIVcpz/HIV-1 lineage, and they are related to SIVsyk in gag and most of pol and related to SIVcpz in env. When comparing the new env sequences with SIVcpzANT, a remarkable conservation is seen in the V3 loop. The 3 viruses, SIVmon, SIVmus, and SIVgsn form a monophyletic lineage within the primate lentivirus family. The 3 Cercopithecus species, infected with a similar SIV, belong each to a different groups in the Cercopithecus genus.
Conclusions: This study presents evidence that different evolutionary groups of Cercopithecus monkeys can be infected with the same SIV lineage. However, additional characterizations of SIVs from the same monkey species from different geographic locations are necessary to find out whether this observation is the result of co-evolution or cross-species transmissions between different groups of the Cercopithecus genus. Furthermore, the predatory behavior of chimpanzees and the findings of SIVs with a similar structure as SIVgsn strengthen our hypothesis on the recombinant structure of the SIVcpz lineage.
