Serological recognition of HLA-DR allodeterminant corresponding to DNA sequence involved in gene conversion

Publisher Website
Google Scholar
Abstract
HLA class 11 molecules were isolated from mouse L cells transfected with a DR α gene and an allele, 52a, of locus DR β III from an HLA-homozygous cell line, AVL, of the DR3 haplotype. The isolated molecules were found to possess a new allospecificity, named TR81. This specificity behaved allelic to the previously described DR β III locus. The TR81 specificity was also present on the DR β I gene product of the DR3 haplotype. The nucleotide sequence of the gene encoding TR81 differs from TR81-negative DR β genes of the DRw52 family in only two codons, both located in the regions known to be involved in a gene conversion event. Consequently, the following conclusions can be formulated. (a) TR81 is a bi-locus specificity and allelic to TR22 only in its DR β III locus localization. (b) The TR81 specificity is the phenotypic counterpart of the gene conversion event which led to the generation of the DR β I gene of the DR3 haplotype. (c) One or both individual amino acid substitutions in the first domain of the DR β chain are responsible for the TR81 allospecificity. (d) Since TR81 is expressed on the DR β I chain of the DR3 haplotype, it is possible that TR81 and DR3 represent the same serological specificity.