HLA-A2 mutants immunoselected in vitro. Definition of residues contributing to an HLA-A2-specific serological determinant.

Abstract

The HLA-A2-specific mouse monoclonal antibody BB7.2 plus complement was used to immunoselect variant clones of the [human neoplastic] lymphoblastoid cell line T5-1 (HLA-A1, -A2, -B8 and -B27). Members of 1 class of variant clones appear to express cell surface HLA-A2 molecules that display reduced reactivity with the selecting antibody, but normal or near normal reactivities with some other HLA-A2-specific monoclonal antibodies and human alloantisera. The HLA-A2 H chains derived from 2 of these variant clones were characterized by comparative double-label tryptic peptide mapping in conjunction with microsequence analysis. These H chains carried distinct mutations in the same peptide in the molecule. Residues within this short segment of the polypeptide apparently contribute to an HLA-A2-specific serological determinant.