Human immunodeficiency virus type 1 intergroup (M/O) recombination in Cameroon

Here we describe, for the first time, recombinants between two highly diver gent major groups of human immunodeficiency virus type 1 (HIV-1), M and O, within a Cameroonian woman infected with three different HIV-1 strains, a g roup O virus, a subtype D virus, and a recently reported IBNG (A/G)-like re combinant virus. Using nested extra-long PCR amplification, we sequenced fr om the pol region to the env region including accessory genes of the viral genome obtained from the patient's uncultured peripheral blood mononuclear cells and examined the phylogenetic position of each gene. Compared with se quential blood samples obtained in 1995 and 1996, there were multiple segme ntal exchanges between three HIV-1 strains (O, D, and IBNG) and all the rec ombinants appeared to be derived from a common M/O ancestor. Importantly, r ecombination between groups M and O occurred, even though the homology betw een these two groups is 69, 76, 68, and 55% in the gag, pal, vif-vpr, and e nv regions, respectively. Recombination between strains with such distant l ineages may contribute substantially to generating new HIV-1 variants.