Structural and functional characterization of hla-dr molecules circulating in the serum

Michael Jendro, Jorg J. Goronzy, Cornelia M. Weyand

Research output: Contribution to journalArticlepeer-review

38 Scopus citations


HLA molecules are highly polymorphic glycoproteins with a single binding site for immunogenic peptides. The complex formed by HLA-DR molecules and peptides is the entity specifically recognized by the antigen receptor of CD4+ helper T lymphocytes. This biological function has been linked to the constitutive cell surface expression of HLA molecules on antigen-presenting cells which provide immunogenic peptides through denaturation or fragmentation of antigen. Here, we report that HLA-DR molecules can be identified in a soluble form circulating in the serum. Biochemical characterization and recognition of such soluble HLA-DR molecules by a monoclonal antibody reactive to conformational determinants on the a-[i HLA complex indicates that they are circulating as intact hetcrodimers. Upon activation, human T cells and B cells release soluble HLA-DR molecules. The expression and secretion of HLA-DR by T lymphocytes is greatly enhanced in the presence of macrophages indicating that the production of HLA-DR molecules might be regulated and controlled through factors derived from antigen-presenting cells. An alloreactive human T cell clone can be stimulated to proliferate in response to soluble HLA-DR molecules purified and enriched from serum suggesting that the soluble form of the natural ligand of the T cell receptor might have immunoregulatory functions.

Original languageEnglish (US)
Pages (from-to)289-296
Number of pages8
Issue number4
StatePublished - 1991


  • Soluble HLA-DR molecules
  • T cell activation
  • T cell recognition

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology


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