Specificity and functional characteristics of anti‐HLA‐A mAbs LGIII‐147.4.1 and LGIII‐220.6.2

Publisher Website
Google Scholar
Abstract
Only three anti‐HLA‐A monoclonal antibodies (mAbs) have been described in the literature. Two of them recognize determinants shared by only a few HLA‐A allospecificities. The third one, mAb 3G11, recognizes a determinant shared by most HLA‐A allospecificities. Being an IgM, the latter mAb is not likely to be a useful probe in immunohistochemical reactions and in functional assays. Therefore, in the present study we have characterized the specificity of the mAbs LGIII‐147.4.1 and LGIII‐220.6.2. The two mAbs that do not share idiotypic determinants recognize distinct but spatially close antigenic determinants expressed on most of the gene products of the HLA‐A locus. Specifically, the determinant recognized by mAb LGIII‐220.6.2 is expressed on HLA‐A1, ‐A2, ‐A3, ‐A26, ‐A28, ‐A29, ‐A30, ‐A33, ‐A36, ‐A74 and ‐A80 allospecificities. The determinant recognized by mAb LGIII‐147.4.1, which appears to be located on the amino‐acid residues 79–83 of the heavy chain, is expressed on all HLA‐A allospecificities but HLA‐A23, ‐A24, ‐A25 and ‐A32. Because of its broad reactivity, the mAb LGIII‐147.4.1 was characterized in a number of assays. It was found to be a useful probe to measure the HLA‐A antigen level in serum, to assess the HLA‐A restriction of cytotoxic T lymphocytes (CTL) and to monitor HLA‐A antigen expression in normal and malignant lesions.