Characterization of DNA and MVA vectors expressing Nef from HIV-1 CRF12_BF revealed its low cross reactivity against Nef B derived peptides

ANA MARÍA RODRIGUEZ; G.TURK; MF.PASCUTTI; JL.NÁJERA; F.FERRER; D.MÓNACO; G.CALAMANTE; M. ESTEBAN; H.SALOMÓN; MM.GHERARDI

Ciudad del Cabo-Sud Africa

Conferencia; AIDS Vaccine 2008 conference; 2008

The Argentine HIV epidemic is characterized by the high prevalence of infections caused by subtype B and BF variants. Nef may be employed as a useful tool to study the impact of HIV-1 BF variants in the design of future vaccines, as it is one of the most HIV variable proteins, having 30% of differences between B and BF. In this work, we describe the generation, characterization, and immunogenicity of DNA and MVA vectors expressing Nef of the BF recombinant form of HIV-1. Nef gene was amplified by PCR from the viral genome from the CRF12_BF of HIV-1, and cloned in a DNA expression vector or in a transference plasmid to generate rMVA and rVV (Western Reserve strain) recombinant viruses. NefBF immunogenicity was analyzed in Balb/c mice, administering different prime/boost schedules. Ten days after the last immunization, the specific cellular immune response induced in the spleen was evaluated with overlapping peptides comprising the full NefBF or NefB proteins. Determinations were made by ELISPOT and quantifying specific IFN-gamma in the supernatant of splenocyte-cultures. Of all the immunization protocols applied, the DNA/MVA and the DNA/DNA/DNA (3xDNA) were the most immunogenic. Interestingly, in these groups in which a significant cellular response against NefBF peptides was detected, the cross-reactivity against NefB peptides was low or non-detectable. However when 3xDNANefBF primed mice were boosted with rVVNefBF, a response of higher magnitude against BF peptides was detected and more importantly, in this case a significant cross-reactivity against NefB peptides was found. NefBF delivered from DNA and MVA vectors generated a response of high specificity with low cross-reactivity against subtype B, but when a more potent response was generated, a significant cross-reactivity against NefB could be detected. These results will be of high relevance in the design of future vaccines for our region.