LB1. Molecular Characterization of a Novel Simian Immunodeficiency Virus with a Vpu Gene from Greater Spot-Nosed Monkeys <i>(Cercopithecus nictitans)</i> from Cameroon

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Session 10 Oral Abstract Session
Late Breakers I
Session Time: Monday, 2 pm - 4 pm
Room 6E

2:00 LB1.

Molecular Characterization of a Novel Simian Immunodeficiency Virus with a Vpu Gene from Greater Spot-Nosed Monkeys (Cercopithecus nictitans) from Cameroon
V. Courgnaud*¹, M. Salemi², X. Pourrut¹, E. Mpoudi-Ngole³, B. Abela³, P. Auzel³, F. Bibollet-Ruche⁴, B. Hahn⁴, A. M. Vandamme², E. Delaporte¹, and M. Peeters¹
¹UR36, Inst. de Recherche pour le Développement (IRD) and Univ. of Montpellier I, France; ²Rega Inst. for Med. Res., KU Leuven, Belgium; ³Projet PRESICA, Hôp. Militaire, Yaounde, Cameroon; and ⁴Univ. of Alabama at Birmingham

Background: Primate lentiviruses are a diverse group that naturally infect a variety of nonhuman African primate species. So far, fully characterized SIVs cluster into 6 distinct lineages: SIVcpz, SIVsm, SIVagm, SIVsyk, SIVlhoest, and SIVcol. During a large seroprevalence survey of wild-born monkeys in Cameroon, we identified 19 greater spot-nosed monkeys (Cercopithecus nictitans) whose sera contained antibodies cross-reacting with HIV-1 envelope gene products.
Methods: To characterize the infecting viruses, we used long PCR method to amplify viral sequences from uncultured PBMC DNA by targeting unintegrated circular DNA. The complete sequences of 2 SIVgsn genomes (SIVgsn-99CM71 and SIVgsn-99CM166) were determined.
Results: Together with SIVsyk, SIVgsn represents the second virus isolated from a monkey belonging to the C.mitis group of the Cercopithecus genus. Full-length genome sequence analysis of these 2 SIVgsn strains revealed that despite the close phylogenetic relationship of their hosts, SIVgsn was highly divergent from SIVsyk. They differ in their genomic organization: SIVgsn codes for a vpu homologue, so far a unique feature of the members of the SIVcpz/HIV-1 lineage; and detailed phylogenetic analyses on various regions of the viral genome indicated that SIVgsn might be a mosaic of sequences with different evolutionary histories. SIVgsn was related to SIVsyk in Gag and most of Pol and related to SIVcpz in Env, with a middle part of the genome that did not cluster significantly with any of the known SIV lineages. When comparing the 2 SIVgsn Env sequences with SIVcpzANT, a remarkable conservation is seen in the V3 loop, indicating a possible common origin for the envelopes of these 2 viruses.
Conclusions: The complex genomic structure of SIVgsn, the presence of a vpu gene and its relatedness to SIVcpz in the envelope suggest a link between SIVgsn and SIVcpz and provide new insights about the origin of SIVcpz in chimpanzees.

Š2002 9^th Conference on Retroviruses and Opportunistic Infections