An Unusual HIV Type 1 env Sequence Embedded in a Mosaic Virus from Cameroon: Identification of a New env Clade

An atypical HIV-1 strain (CAM001) was identified in a pregnant Cameroonian woman in 1995. HMA subtyping of the env region was unsuccessful, and sequence analyses were performed. Unique sequence motifs were found at the V3 tip (GAGRALHA and GAGRAWIHA), and phylogenetic studies showed that the env C2-V5 sequence branched within group M but remained distinct from all known HIV-1 subtypes, while p17 gag branched with the subtype F sequences. Four other HIV group M viruses, undetermined by HMA, of African origin were found to cluster with CAM001 in the C2-V5 sequences. With the BLAST method, we found in databases three strains whose V3 sequences also clustered with CAM 001. These unusual env sequences from eight HIV-1 strains derived from Cameroon formed a separate cluster in HIV-1 group M, which we designated k.