IDENTIFICATION OF A NEW HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 DISTINCT FROM GROUP-M AND GROUP-O

A highly divergent HIV-1 isolate, designated YBF 30, was obtained in 1 995 from a 40-year-old Cameroonian woman with AIDS. Depending on the g enes studied, phylogenetic analysis showed that YBF30 branched either with SIVcpz-gab or between SIVcpz-gab and HIV-1 group M. The structura l genes and tat vpr, and nef of YBF30 are approximately equidistant fr om those of HIV-1 group M and SIVcpz-gab. In contrast, vif and rev are closer to HIV-1 group M, and vpu is highly divergent. Using a YBF30 V 3 loop peptide enzyme immunoassay, we screened 700 HIV-l-positive sera collected in Cameroon; three reacted strongly with the YBF30 peptides and one was confirmed as being related to YBF30 by genetic analysis o f a pol fragment. YBF30 is as distinct from SIVcpz-gab as it is from H IV-1 group M and can thus be considered as the prototype strain of a n ew human immunodeficiency virus group.