PARTICIPATION OF CATHEPSIN-B IN PROCESSING OF ANTIGEN PRESENTATION TOMHC CLASS-II

Cellular and humoral immune responses to vaccines of hepatitis B type and rabies were inhibited by specific inhibitors of cathepsin B, speci fic synthetic substrates of cathepsin B and anti-cathepsin B antibody. Therefore the lysosomal cathepsin B of antigen presenting cells plays an essential role in processing of these antigens for presentation to MHC class II. One of the active sites of cathepsin B, VN217-222 Share s highly homologous sequences with a part of the desetope, a binding d omain of antigenic peptides, VN57-62 of MHC class II, beta-chain. This evidence suggests that the peptides processed by the substrate specif icity of cathepsin B exhibit a common affinity to bind with the deseto pe of MHC class II, beta-chain.