Phylogenetic analysis of a new chimpanzee lentivirus SIVcpz-gab2 from a wild-captured chimpanzee from Gabon.

OF A TOTAL OF 50 chimpanzees wild-captured in different O areas of the tropical iain forest in Gabon, two were found to be positive for HIV-1 antibodies.’ From one chimpanzee a lentivirus, sIv,z,ab, was isolated. As a result of virological and molecular studies it was classified as an HIV-l-related nonhuman Subsequently, another chimpanzee lentivhs, SIVEpz-mo has been isolated from a wild-captured chimpanzee from Zaire? Its molecular features are under study. Here we report genetic evidence for infection of the second seropositive Gabonese chimpanzee’ with an HIV-l-like lentivirus. This chimpanzee was about 2 years old when the mother was killed by hunters in the tropical rain forest of northeastern Gabon. The animal stayed for 2 days in a village after having been shot. It was then brought to the primatology center of the Centre Intemational de Recherches Médicales de Franceville (CIRM, Franceville, Gabon) for medical care, where it died of its wounds 1 week later. To the best of our knowledge, the animal had no history of inoculation with human blood products. From this chimpanzee, we have been unable thus far to isolate a lentivhs, but some of the primary peripheral blood mononuclear cells (PBMCs) have remained available in a frozen state. To investigate the genetic relationship to the sIv,z-gab isolate, proviral DNA was extracted from these primary PBMCs, and a 280-base pair (bp) fragment of the pol gene was amplified by a nested polymerase chain reaction (PCR)! Subsequently PCR fragments were cloned and sequenced. The newly obtained sequences were aligned with the corresponding pol gene fragments of strains belonging to different HIV-1 subtypes, sIvcpz-gab and HIV-2ROD,5*6 and a phylogenetic tree was generated (Fig. l)? The resulting phylogenetic tree corresponded with the phylogenetic tree based on the fulllength pol gene for the isolates €or which this information was available. The new strain, referred to as sIvcpz-gab2, was positioned as an outlier of the HIV-1 group of viruses, containing genotype A, B, and D sequences, and was found to be genetically equidistant to the other viruses classified in the “outlier”