Strong antibody reactivity to HIV-1 synthetic peptides in seropositive indigenous Warao people.

INTRODUCTION: Previous studies have described an epidemic of HIV-1 in the indigenous Warao population living in the Orinoco Delta, Venezuela. The Warao face extraordinary challenges amid of their ongoing HIV-1 epidemic, the highest reported HIV-1 prevalence in indigenous groups (9.6%) in South America. OBJECTIVE: To investigate the antibody reactivity to HIV-1 synthetic peptides in seropositive individuals, with a particular focus on the indigenous Warao population from Venezuela. MATERIALS AND METHODS: The HIV-1 Pol region from infected patients' isolates was amplified, sequenced, and analyzed using phylogenetic tools. Custom-designed synthetic peptides were derived from conserved regions of HIV-1 glycoproteins 41 and 120, based on reference sequences. Multiple antigen blot assays were used to evaluate the presence of antibodies against synthetic peptides. RESULTS: The most frequent HIV-1 subtype was B, the most common in Venezuela, although some individuals were infected with subtype A1. Distinct patterns of reactivity to synthetic peptides were observed between the sera of the general population and the Warao population; the sera of the latter exhibited a high intensity of peptide recognition. CONCLUSIONS: The use of synthetic peptides, coupled with the robust performance of multiple antigen blot assays, enriches our understanding of antibody responses in different HIV-1-infected populations.