Allele and locus‐specific differences in cell surface expression and the association of HLA class I heavy chain with β2‐microglobulin: differential effects of inhibition of glycosylation on class I subunit association

摘要

AbstractThe assembly of HLA class I antigens, and the contribution of the single N‐linked glycan to this process were examined. We observed a requirement for N‐linked glycosylation in the proper assembly and surface expression of HLA‐B locus products in particular, although considerable variation was seen within the allelic series of the HLA‐A and B loci. We conclude that the single N‐linked glycan can contribute in a major way to that conformation of the heavy (H) chain which is competent to associate with the light chain β2‐microglobulin, and that the presence, rather than the type, of carbohydrate chain is important in this respect.The association of human class IH chains with β2‐microglobulin shows biphasic kinetics, where an initially rapid phase is followed by a prolonged period during which no further association can be measured. It appears that HLA‐C H chains are initially synthesized in amounts similar to HLA‐A and B H chains, but associate inefficiently with β2‐microglobulin, resulting in low expression of HLA‐C at the cell surface. The individual stages of assembly and maturation of class I antigens including the transfer from Golgi to cell surface were found to display characte