GP41 peptide biomarkers of chronicity of HIV infection identified through PepScan Epitope Approach

Background: Human immunodeficiency virus (HIV) is a retrovirus that integrates its genetic material into the host genome and establishes as a permanent chronic infection. HIV-1 infected individuals develop antibodies to gp41and the immune response varies from early to chronic stage of infection. We, therefore, performed studies to identify epitopes in the gp41 proteins that could potentially serve as biomarkers for changes in epitope recognition during disease progression. Method: Peptides of 20-mer with an overlap of 10 amino acids having two extra lysine at the N-terminus were synthesized for gp41 and were coated on to 96 well microplate. These peptides were evaluated using a europium nanoparticle-based immunoassay (ENIA) for binding of antibodies from patients who had recent or longstanding HIV -1 infection. We tested HIV-negative plasma control and calculated the signal ratio between negative and positive plasmas. Results: and conclusion: We identified three contiguous gp41 peptides gp16, gp17 and gp18, which elicit strong antibody reactivity with plasma from persons with long standing infection and little or low reactivity with recent infections. These three gp41 peptides showed consistent positive reactivity in different sets of well characterized long standing HIV infected patient Plasmas and negative or very low response in recently infected plasma.