Phylogenetic analysis of HIV-1 archived DNA in blood and gut-associated lymphoid tissue in patients receiving antiretroviral therapy: a study from Provir/Latitude45 project

Abstract

One of the approaches to cure HIV is the use of therapeutic vaccination. We have launched the Provir/Latitude 45 study to identify conserved CTL epitopes in archived HIV-1 DNA according to the HLA class I alleles in aviremic patients under antiretroviral therapy (ART). A HIV-1 polypeptidic therapeutic vaccine based on viral sequence data obtained from circulating blood was proposed; here, our aim was to compare the proviral DNA in blood and gutassociated lymphoid tissue (GALT) at two different levels : nucleotide sequences and potential CTL epitopes. The reverse transcriptase was sequenced in both compartments using next generation sequencing (NGS) in samples from nine individuals, two of which had also single genome sequencing (SGS) performed; phylogenetic trees were established and compared ; CTL epitopes were also identified according to their potential affinity for the HLA alleles .The proviral sequences of both compartments intra-patient exhibited a very low genetic divergence while it was possible to differentiate the sequences inter-patients; SGS analysis of two couples of samples confirmed that there was not a compartmentalization of the sequences intra-patient.When we simulated the CTL epitopes which can be presented by the corresponding HLA alleles in both compartments, no significant difference was observed. We conclude that the proviral DNA sequences in blood and GALT are similar and that the epitope analysis in blood can be considered as relevant to that observed in the GALT, a hard-to-reach major compartment, and can therefore be used for therapeutic vaccine approaches. KeywordsHIV-1, proviral DNA, blood, gut associated lymphoid tissue (GALT), CTL epitopes, phylogenetic comparison of archived viral sequences