Physical Association between the CD8 and HLA Class I Molecules on the Surface of Activated Human T Lymphocytes

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 85; no. 11; pp. 3985 - 3989
• Main Authors: Bushkin, Yuri, Demaria, Sandra, Le, Junming, Schwab, Rise
• Format: Journal Article
• Language: English
• Published: Washington, DC National Academy of Sciences of the United States of America 01.06.1988; National Acad Sciences
• Subjects: Analysis of the immune response. Humoral and cellular immunity; Antibodies; Antigens, Differentiation, T-Lymphocyte; Biological and medical sciences; CD8 Antigens; Chemical Precipitation; Fundamental and applied biological sciences. Psychology; Fundamental immunology; HLA Antigens; Humans; Immunobiology; Immunologic Techniques; Lymphocyte Activation; Macromolecular Substances; Membrane Glycoproteins; Molecular chains; Molecular Weight; Molecules; Monoclonal antibodies; Natural killer cells; Organs and cells involved in the immune response; Peptide Mapping; Precipitates; T lymphocytes; T-Lymphocytes - immunology; T-Lymphocytes - ultrastructure; Thymocytes; Antigen; Human; T-Lymphocyte; Molecular interaction; Activation; Cellular immunity; Cell differentiation; Cell surface; Class I histocompatibility antigen
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.85.11.3985

Immune recognition by cytotoxic effector T cells requires participation of the CD8 and major histocompatibility complex class I antigens. We found that the CD8 molecule is noncovalently associated with the HLA class I heavy chain on the surface of human T cells activated by Con A. Accordingly, anti-CD8 monoclonal antibodies precipitated a heterodimer containing polypeptides of 32 and 43 kDa from the lysates of activated T cells. The 43-kDa chain of this heterodimer can be adsorbed from cell lysates with anti-HLA-A, -B, and -C antibodies. Endoglycosidase F treatment and chymotryptic peptide mapping identified a structural similarity between this 43-kDa molecule and the HLA class I heavy chain precipitated by the anti-HLA-A, -B, and -C antibody W6/32. Analysis of anti-CD8 precipitates under nonreducing and reducing conditions indicated a lack of interchain disulfide bonding between the CD8 and HLA heavy chain molecules. The CD8-HLA heavy chain complex was also detected in mixed lymphocyte cultures and a cloned cytotoxic T-lymphocyte line but not in purified natural killer cells. The present study indicates that CD8 is complexed with HLA heavy chain on the same cells, and the complex may have functional relevance in the T-cell recognition process.