Characterization of LMP polymorphism in homozygous typing cells and a random population

Within the class II region of the MHC are several genes whose products are involved in processing antigen for HLA class I presentation. Two such genes , LMP2 and LMP7, encode produces that are incorporated into a multicatalyti c proteinase complex which serves as the major pathway for protein degradat ion for class I peptide presentation. Polymorphic residues have been identi fied in bot h LMP2 and LMP7. In this report, we describe an ARMS-PCR method to distinguish LMP7 alleles. We applied this method to characterize these alleles in addition to LMP2 alleles in 50 homozygous typing cells (HTC) as well as in a panel of 110 random individuals. Of the four possible combinat ions of LMP2 and LMP7, we observed three in the HTC population, while all f our were observed in the random population. The frequencies at which allele combinations were observed were similar to that predicted by individual al lele frequencies. We also analyzed the possibility of linkage disequilibriu m of LMP2 and LMP7 alleles with TAP1, TAP2, and specific HLA class I allele s in both populations. From this data, there seems to be no apparent linkag e disequilibrium and no indication that particular combinations of LMP2 and LMP7 have been maintained. Human Immunology 60, 145-151 (1999). (C) Americ an Society for Histocompatibility and Immunogenetics, 1999. Published by El sevier Science Inc.