HIV-1 patient serum antibodies that bind the 3F5-recognized gp120 epitope are the same antibodies that bind and inactivate α1PI.

aSera were selected from HIV-1 infected subjects with undetectable HIV RNA (n = 13) or from HIV-1 uninfected subjects (n = 9). Of the 22 sera tested, only 5 exhibited increased α1PI activity in the presence of SHIV, and these 5 were the only specimens that were also positive for IgG-α1PI immune complexes (A490nm>0.5). Immune complexes were undetectable in the other 17 sera and none of those sera exhibited a difference in α1PI activity in the presence of SHIV (Mean difference = 0.7 µM±1 µM).