HIV-1 Naturally-Occurring BF Intersubtype Recombination in Gag-Protease Is Associated to Reduction in Viral Replication Capacity.

C. ESPADA; F. MELO; P.M. ZANOTTO; L. MARTÍNEZ PERALTA; M.G. CAROBENE

Barcelona

Congreso; Aids Vaccine 2013; 2013

Global HIV Vaccine Enterprise

Background: HIV-1 recombination may have a major impact on the global epidemic since the intersubtype recombinant variants might exhibit differential biological behaviors. gag and pol are closely related genes as both polyproteins precursors are cleaved by the viral protease. Gag is known to be targeted by the host CTL response and to be involved in the antiretroviral treatment outcome. We evaluated the consequences of intersubtype recombination in gag-protease by comparing the in vitro viral replication of pure subtype B vs BF recombinants variants, highly represented in South America. Methods: CRF12_BF-like and CRF28_BF-like gag-protease sequences from two HIV-infected subjects were used to construct chimeric NL4-3- derived viral variants: pNL-Bst (subtype B), pNL-CRF12_BF-like and pNLCRF28_BF-like. Viral stocks were generated by transfecting HEK293T cells using Lipofectamine 2000 (Invitrogen). MT2 cell cultures were infected with equal amounts of p24 antigen (300 ng) of each viral stock. Viral replication capacity (RC) was examined by quantifying p24 antigen (Murex, Abbot) in cell culture supernatants every 24 h. Statistical analysis was performed using GraphPad software. Results: Although at 24 h pi, NL-CRF12_BF-like RC was significantly higher than that of NL-Bst (p24= 1.7 vs. 0.55 ng/ml, p=0.0001), at 48 and 72 h pi no statistically differences were observed (p>0.05). Surprisingly, at 96 h, NL-CRF12_BF-like showed significantly lower RC than NL-Bst (p24= 749333 vs. 1672000 ng/ml, p=0.002). In contrast, the RC of the NL-CRF28_BF-like variant was lower than both, NL-Bst and NL-CRF12_BF-like at all times points (p24= 0.4, 0.6, 2.1 and 10 ng/ml, p