Isolation and envelope sequence of a highly divergent HIV-1 isolate: definition of a new HIV-1 group.

We report here the isolation and envelope sequence of a divergent HIV-1 isolate from a French woman with AIDS. This virus, HIV-1VAU, is closely related to the recently described Cameroonian viral isolates HIV-1ANT70 and HIV-1MVP5180, until now designated HIV-1 subtype O. Phylogenetic analysis reveals that the three viruses are equidistant from one another and that their mutual divergence is similar to what has been reported between the more conventional HIV-1 subtypes. Therefore, these three viruses could be included in a new viral group, HIV-1 group O (outgroup), distinct from the cluster of other HIV-1 isolates, which we will refer to as group M (Major group). The HIV-1 group O is currently emerging in western central Africa but its spread in Europe has already started.