Genetic characterization of HIV type 1 and type 2 from Bissau, Guinea-Bissau (West Africa)

Previous studies from Guinea-Bissau (West Africa) have demonstrated a uniqu e epidemiology with respect to both HIV-I and HIV-2 infection. In order to evaluate the prevalence and dynamics of HIV-1 and HIV-2 subtypes in Bissau, the capital city of Guinea-Bissau, a cross-sectional study was set up usin g serological and molecular techniques. Plasma samples from 103 individuals were screened for HIV-I and HIV-2 antibodies by ELISA and Western-blot. Se ropositive results were confirmed by PCR amplification of proviral sequence s in primary peripheral blood mononuclear cells (PBMC) with enu and LTR pri mer sets for HIV-2 and env, LTR and pol primers for HIV-1. A total of 38/10 3 individuals were HIV-seroreactive (four HIV-1, 15 HIV-2, 19 HIV-1/HIV-2). A total of eight out of 19 dually seropositive specimens showed double PCR amplification of HIV-I and HIV-2 proviral sequences, accounting for 21% of the infected individuals. In the remaining 11 individuals either HIV-2 or HIV-I sequences were detected, the majority (n = 9) amplifying only HIV-2. These screening data demonstrate a high discrepancy between serology and PC R results for dually seroreactive samples, Western-blot giving an overestim ation of double infection. Additionally, HIV-I strains were subtyped by het eroduplex mobility assay (HMA) on the basis of gp120 sequences. Subtyping o f HIV-2 was carried out by DNA sequencing and phylogenetic analysis of env V3 molecular clones. For both HIV-1 and HIV-2 strains circulating in Bissau , our results indicate dominance of subtype A. (C) 2000 Elsevier Science B. V. All rights reserved.