Rapid in vitro assembly of class I major histocompatibility complex

The class I major histocompatibility complex (MHC) molecule consists of a highly variable heavy chain in complex with a light chain (β₂-microglobulin, β₂m) and peptides of approximately 8–10 amino acids in length. This chapter describes a novel method for the rapid assembly of properly folded MHC ternary complexes in relatively high yields, utilizing exogenous synthetic peptides and over-expressed polypeptides from inclusion bodies. The method is reproducible, and capable of rapidly and efficiently forming stable ternary complexes. The presence of glutathione in the incubation mixture is essential, emphasizing that during the refolding process proper formation of disulfide bonds is critical, and is consistent with the observation that, there are no free sulfhydryl groups in initially solubilized heavy chain, suggesting that mispaired disulfide bonds prevent the correct folding to ternary complex. The adaptability of the method to analysis of multiple samples facilitates screening of peptide variants, and consequently, the study of the rules for epitope binding. Because of the efficient manner by which MHC ternary complexes can be formed, this method has potential for rapid screening of peptide analogues, possibly by radio assay, or for use in equilibrium and kinetic studies.