cDNA clones coding for the heavy chain of human HLA-DR antigen.

Abstract

Two c[complementary]DNA clones, pDRH1 and pDRH2, containing sequences specific for human HLA-DR antigens were isolated from a bank of cDNA clones made from partially purified HLA-DR mRNA from the human lymphoblastoid cell line Maja. The clones were specific for the MW 34,000 HLA-DR antigen glycoprotein chain. The identity of these clones was established by their ability to hybridize specifically to HLA-DR mRNA in a positive selection assay; mRNA species hybridizing to the cDNA clones were expressed in B-cell but not in T-cell or fibroblast cell cultures; and a nucleotide sequence in the longer clone, pDRH2, could be translated into an amino acid sequence that is identical to the limited NH2-terminal amino acid sequence available for the purified HLA-DR antigen MW 34,000 chain. Analysis of DNA from human, mouse and human-mouse somatic cell hybrid lines by Southern transfer of restriction endonuclease digests indicated the HLA-DR H chain is encoded in chromosome 6. This finding is compatible with the location of at least 1 of the HLA-D/DR H chain genes in the HLA region. The sequences coding for HLA-DR H chain appear to be present in only 1 or a few copies in the genome and to be relatively simple in structure.