Limited regions or immunogenic domains have been found on the envelope of human immunodeficiency virus type 1 (HIV-1) which evoke some form of antiviral immunity which is therefore a concern for developing effective immunoprophylactics or immunotherapeutics. One particular immunogenic region, termed V3, exhibits both neutralIzation, cell fusion inhibition and antibody-dependent, cellular-mediated cytotoxicity and cell-mediated activity against it; although, in addition, it is characterized as a hypervariable domain. Subunit approaches for vaccine development are being considered as a means to obviate those regions of the HIV-1 envelope which may cause immune dysregulation. T helper sites were coupled to the V3 region by peptide chemistry in an attempt to elicit a more robust and broader immune response to this functional epitope. A high titered restricted response resulted, which demonstrated a discrepancy between binding antibody titers and neutralization titers. Recent methods in generating human monoclonal antibodies by recombinatorial libraries has allowed for a larger array to be tested. Fab's and whole IgG are demonstrating functional properties, such as neutralization, and are being evaluated as reagents to look for new conserved epitopes on HIV-1. Immunologically relevant parameters of HIV-1 neutralization appear to involve viral age, cell concentration, valency, state of the virion and reversibility. These studies indicate that, for the most part, monoclonal antibodies to date are not as potent as professed in the literature. An effective means, however, for their evaluation now exists in the laboratory.
