Genetic Variability of Human Immunodeficiency Virus Type 2 C2V3 Region within and between Individuals from Bissau, Guinea-Bissau, West Africa

Abstract

The V3 loop of both HIV-1 and HIV-2 is characterized by a high degree of genetic variation. To investigate the spectrum of HIV-2 variability in nature we have focused on the C2V3 region of Env and analyzed 108 viral sequences obtained from uncultured peripheral blood mononuclear cells obtained from 16 HIV-2-seropositive individuals from Bissau (Guinea-Bissau). The estimated values of genetic divergence between individuals were higher than those calculated from sequence information collected in a single individual. We have also found that the sequences surrounding the V3 loop contribute significantly to the overall genetic diversity of the C2V3 region of HIV-2 gp105, while the V3 loop itself seems to be rather conserved. Phylogenetic analysis demonstrated that all the individuals enrolled in this study were infected with HIV-2 subtype A viruses.

The role of the humoral immune response in the molecular evolution of the envelope C2, V3 and C3 regions in chronically HIV-2 infected patients

“…These results are in agreement with previous reports that have examined the C2V3C3 region [22,24] and with the observation that, globally, the HIV-2 env gene is under purifying selection [25]. Consistent with previous studies of a cross-sectional nature, we found that C2 and C3, but not V3, were the fastest evolving regions at the nucleotide and amino acid level contributing significantly to the high within-patient nucleotide divergence rate [22,63]. The conservation of the V3 region in vivo implies that in HIV-2, as in HIV-1, this region is submitted to strong structural and conformational constraints which are probably related to its crucial functional roles at the level of coreceptor binding and cell entry [29-32].…”

Profile of the HIV Epidemic in Cape Verde: Molecular Epidemiology and Drug Resistance Mutations among HIV-1 and HIV-2 Infected Patients from Distinct Islands of the Archipelago

“…Lower frequency of children infected by vertical transmission was observed for HIV-2 (2.3%) compared with HIV-1 (16.0%) infected individuals, as described for other countries where both types circulate [33], [34]. All HIV-2 samples belonged to the predominant group A, as previously described in Cape Verde [18] and other West African countries [35], [36]. Analyzing the HIV-2 group A samples according to the region of origin, we observed the presence of one highly supported cluster that included the majority of samples from the Barlavento region, suggesting possible independent introductions and/or distinct dynamics of the HIV-2 distribution among Cape Verde islands.…”

Molecular Epidemiology of HIV Type 2 Infections in South India

“…This was significantly lower than the V3 sequence heterogeneity observed in HIV-1, which could be as high as 6.1%. Another study by Parreira et al 13 estimated that the values of HIV-2 genetic divergence between infected individuals were higher than those calculated from sequence information collected in a single individual. They also found that sequences surrounding the V3 loop contribute significantly to the overall genetic diversity of the C2V3 region of HIV-2 gp105, while the V3 loop itself seems to be conserved.…”

“…They also found that sequences surrounding the V3 loop contribute significantly to the overall genetic diversity of the C2V3 region of HIV-2 gp105, while the V3 loop itself seems to be conserved. 13 Grez et al 2 reported the intrapatient diversity in a 346-bp stretch encompassing the V3 stretch in a single sample from India to be 3.6% on sequencing three clones from one patient. 2 Similarly, on analyzing multiple clones from seven subjects in this study, the mean quasispecies diversity of the HIV-2 envelope C2V3C3 sequences in a single sample was found to be 3.5%.…”