ABSTRACT
"In order to identify HIV-1 strains prevalent in Northern Uganda; peripheral blood mononuclear cells (PBMC) of 19 asympotomatic seropositive pregnant women from the District of Gulu-Northern Uganda have been analysed. A 700bp fragment of the HIV-1 env gene; including the V3-V5 region; amplified by Polymerase chain Reaction (PCR) from 10 samples (52.6); was subjected to both heteroduplex Mobility Assay (HMA); for genetic subtyping; and DNA sequence analysis; for nucleotide comparison and phylogenetic studies. The results show the presence of HIV-1 ""A"" and ""D"" subtypes/clades with a strong prevalence; in this rural area; of the ""A""(8/10) over the ""D"" subtype (2/10) unlike what was previously reported in Uganda. By pairwise comparison analysis; the percentage of sequence divergence is low among samples within each subtype (average inter-subtypes divergence of 23). At the aminoacidic level; the two HIV-1 groups are clearly distinct by a tetrameric GPGQ sequence at the V3 loop apex for the A and a GPGR sequence for the D clade. In addition; 10 out of the 19 viral samples (52.6) have been isolated in vitro and 9 of them have been classified as Rapid/High (R/H); showing the high in vitro replication capacity to field isolated also when obtained from asymptomatic individuals. These data; even though on a limited sample size; suggest that in Uganda HIV-1 isolates can be prevalently grouped in 2 major clades; and the comparison of Gulu HIV-1 sequences with the two consensus sequences (Group A and B) identified by Albert et al 1990; indicates that in a 4-year period no major genetic shifts have occurred. These results should be extremely relevant for Uganda future HIV-1 vaccine programs. Supported by Ministero Italiano Sanita (Ric.Corr.1994) and ISDC-World Laboratory; Lausanne (Project MCD-2/7)."