INHIBITION OF CLASS-II MHC-PEPTIDE COMPLEX-FORMATION BY PROTEASE INHIBITORS

Studies on the kinetics of antigenic peptide binding to major histocom patibility complex class II molecules have been used extensively to pr obe major histocompatibility complex (MHC) structure as well as to inv estigate the molecular mechanism of peptide recognition. Previous expe riments have frequently been carried out in the presence of a cocktail of protease inhibitors to inhibit the proteolysis of MHC heterodimers . By using high performance size exclusion chromatography to measure f luorescent peptide binding to MHC protein, we have found that the addi tion of a commonly used mixture of protease inhibitors leads to a sign ificant reduction in peptide binding to the class II heterodimer.