SYNTHETIC PEPTIDE ELISA CAN PREDICT AN ANTISERUM'S ABILITY TO NEUTRALIZE A SPECIFIC STRAIN OF THE HUMAN IMMUNODEFICIENCY VIRUS TYPE 1

Abstract

In order to better understand the specificity of the immune response toward infection with the human immunodeficiency virus type 1 (HIV-1), an enzyme-linked immunosorbent assay (ELISA) was developed for the detection of specific antibodies to HIV-1 using synthetic peptides mimicking a specific immunodominant hypervariable epitope (V3) of the gp120 envelope glycoprotein. Antibodies raised during the natural HIV-1 infection have been found to bind synthetic V3 peptides in either a strain or cross-strain specific manner when measured either by ELISA or neutralization assays. A direct relationship between the strain or cross-specificity of both V3 binding and neutralizing antibodies has not been well studied. In this study, short peptides were synthesized that mimic the V3 loop region of the gp120 molecule of two genomic variants of HIV-1 and used to screen HIV-1 positive serum samples for the presence of mono-reactive and cross-reactive antibodies. These were further characterized for cross-reactivity in a soluble peptide competition ELISA and their ability to neutralize HIV-1 in a strain or cross-strain specific manner. For the selected panel of representative antisera used in this study, a good correlation was found between specific reactivity in the synthetic peptide ELISA and their ability to neutralize HIV-1 in a strain and cross-reactive manner. This type of methodology may allow for a more rapid and easier way to identify various circulating viral strains for vaccine development in the ongoing worldwide epidemic.