Analysis of Antibody Interactions with HIV-1 Envelope Expressed on the Surface of Acutely Infected H9 Cells

Protective antibody responses against HIV-1 have yet to be identified or determined. HIV-1 envelope gpl20/gp41 is known to exist as a multimer (tetramers or trimers) on the surface of the virion (1-4). A number of immunoassays have been developed to evaluate HIV-1-specific binding antibody responses using peptides, fusion proteins, and recombinant proteins. Attempts to correlate antibody binding parameters with in vitro HIV-1 neutralization capacity have identified correlations between the presence of V3 antibodies and the capacity to neutralize T-cell line adapted strains of HIV-1. However, no correlation with neutralization of primary HIV-1 isolates and v3 antibodies have been identified (5). Furthermore, binding to monomeric forms of gpl20 has shown little correlation with neutralization of the homologous primary HIV-1 indicating that epitope accessibility and tertiary structure of monomeric forms of gpl20 differs from quaternary structure of membrane expressed oligomeric gpl20/gp41 (6-8).