Relative binding affinity of anti-V3 antibodies to HIV-1 derived peptides and proteins. The binding pattern of anti-V3 mAbs derived from Indian donors (red) and 447-52D (an anti-V3 Ab isolated from HIV-1 subtype-B infected American individual) (green) to consensus-C and B V3 peptides (1A), and subtype-C (Du156.12) and subtype-B (JRFL) derived envelope gp120 proteins (1B). The binding of anti-V3 mAbs was tested by ELISA using mAbs at a concentration ranging from 10 to 0.00003 μg/ml (12 dilutions). Human anti-parvovirus B19 mAb 1418 was used as negative control. Relative reactivity of anti-V3 plasma antibodies to consensus-B and C V3 peptides is shown in terms of 50% ELISA binding titers (Max50) for three patients from whom antibodies were generated (1C). Two plasma samples 277 and 904 showed cross clade reactive binding while 903 displayed subtype-C specific binding.