Anti-HLA-A2 CREG antibodies were purified from seven individuals by affinity chromatography. The binding of the purified antibodies to single or multiple amino acid variants of HLA-A2.1 was measured with an inhibition RIA. Substitutions at 10 amino acid residues in the polymorphic α1 and α2 domains were important for human antibody binding; eight of these have previously been shown to be important in the binding of murine anti-HLA-A2 CREG antibodies. Unlike any previously reported murine mAbs, the binding of antibodies from two individuals was eliminated by a substitution at the HLA-A2, -24, -28 shared loop amino acid residue lysine 127. Conversely, when the asparagine at residue 127 on the non-cross-reactive HLA-A3 was replaced with lysine, antibody binding was completely restored. The results further suggest that both λ- and κ-containing human antibodies that bind to this region may recognize lysine 127 as a haptenlike epitope. Anti-HLA-A2 antibodies that recognized a conformational epitope defined by changes at glycine 62 in the α1 domain were predominanted by λ light chains whereas those that recognize an epitope defined by a loop residue at tryptophan 107 in the α2 domain were predominated by κ light chains. The data are consistent with a model of restricted epitope recognition of HLA-A2 by human B cells that is similar to, but distinct from, epitope recognition by mouse B-cell hybridomas, and may help to explain the phenomenon of public or cross-reactive idiotypes in the HLA system.
|Number of pages||13|
|State||Published - Jul 1993|
Bibliographical noteFunding Information:
The authors acknowledge Dr. Jeffrey Frelinger for kindly providing the R170G mutant used in these studies, Dr. Dennis Heisey for statistical analysis of data, and Wendy Schurer for purification of native HLA-A2. This work was supported in part by National Institutes of Health (NIH) grants 1-R01-DK31774 and 1-R01-AI26941 (W.B., L.D., E.J.-G.); by NIH General Clinical Research grant M01RR03186 (W.B.); by ACS Institutional Research grant 1-R01-IN-170-B and NIH grant 1-R01-AI29574 (K.H.); and by NIH grant 1-R29-AI27879 (C.L.).
ASJC Scopus subject areas
- Immunology and Allergy