Differential recognition of epitopes present on monomeric and oligomeric forms of gp160 glycoprotein of human immunodeficiency virus type 1 by human monoclonal antibodies

The mechanism of infectivity neutralization of human immunodeficiency virus type 1 (HIV-1) by Ig is poorly understood. Three human monoclonal antibodi es (mAbs 1b12, 2G12 and 2F5) that are able to neutralize primary isolates o f HIV-1 in vitro have been shown to act synergistically. In the present stu dy this synergy was analyzed by measuring the epitope accessibility and bin ding kinetics for these three mAbs with respect to monomeric and oligomeric env protein gp160 IIIB using surface plasmon resonance. The results indica te that oligomerization of gp160 affects the accessibility of some of the e pitopes recognized by the mAbs and provide some insight into the mechanism of synergy between different anti-(HIV-1) mAbs.