Interpatient genetic variability of HIV-1 group O

Objective: To analyse the genetic and phylogenetic characteristics of HIV-1 group O viruses. Materials and methods: The env gene, encoding the gp160 glycoprotein, and a partial p24-encoding gag gene fragment of a Cameroonian (CA9) and a Gabone se (V1686) HIV-1 group O virus, isolated from cultured peripheral blood mon onuclear cells of symptomatic patients, were sequenced, aligned with other representatives of group O for which the same region has been documented, a nd genetically and phylogenetically analysed. Results: Phylogenetic analysis of the env gene (gp160) revealed that CA9, V 1686, ANT70, and four Ha strains formed a separate cluster, which was suppo rted by 100% of all bootstrap trees. In addition, these seven isolates were part of the same clade in the p24 phylogeny. VAU and MVP5180 may represent two other subtypes. Conclusion: We have characterized two group O viruses, originating from Cam eroon and Gabon, which show a close evolutionary relationship to ANT70 and four Ha strains based on the entire env gene, suggestive of a first group O subgroup, tentatively named the HIV-1 group O env ANT70 clade or subtype. (C) 1999 Lippincott Williams & Wilkins.