Peptain-1 or peptain-1 incubated with antibody

alphaB-Crystallin is a member of the small heat shock protein family. It is a molecular chaperone and an anti-apoptotic protein. Previous studies have shown that the peptide ((73)DRFSVNLDVKHFSPEELKVKV(93), hereafter referred to as peptain-1) from the core domain of alphaB-crystallin exhibits both chaperone and anti-apoptotic properties similar to the parent protein. We developed a mouse monoclonal antibody against peptain-1 with the aim of blocking the functions of alphaB-crystallin. The antibody reacted with peptain-1, it did not react with the chaperone peptide of alphaA-crystallin. The antibody strongly reacted with human recombinant alphaB-crystallin but weakly with Hsp20; it did not react with alphaA-crystallin or Hsp27. The antibody specifically reacted with alphaB-crystallin in human and mouse lens proteins but not with alphaA-crystallin. The antibody reacted with alphaB-crystallin in human lens epithelial cells, human retinal endothelial cells, and with peptain-1 in peptain-1-transduced cells. Unlike the commercial antibodies against alphaB-crystallin, the antibody against peptain-1 inhibited the chaperone and anti-apoptotic activities of peptain-1. The antibody might find use in inhibiting alphaB-crystallin's chaperone and anti-apoptotic activities in diseases where alphaB-crystallin is a causative or contributing factor.