Cell-cell adhesion mediated by CD8 and MHC class I molecules.
CD4 and CD8 are cell-surface glycoproteins expressed on mutually exclusive subsets of peripheral T cells. T cells that express CD4 have T-cell antigen receptors that are specific for antigens presented by major histocompatibility complex class II molecules, whereas T cells that express CD8 have receptors specific for antigens presented by MHC class I molecules (reviewed in ref. 1). Based on this correlation and on the observation that anti-CD4 and anti-CD8 antibodies inhibit T-cell function, it has been suggested that CD4 and CD8 increase the avidity of T cells for their targets by binding to MHC class II or MHC class I molecules respectively. Also, CD4 and CD8 may become physically associated with the T-cell antigen receptor, forming a higher-affinity complex for antigen and MHC molecules, and could be involved in signal transduction. Cell-cell adhesion dependent CD4 and MHC II molecules has recently been demonstrated. To determine whether CD8 can interact with MHC class I molecules in the absence of the T-cell antigen receptor, we have developed a cell-cell binding assay that measures adhesion of human B-cell lines expressing MHC class I molecules to transfected cells expressing high levels of human CD8. In this system, CD8 and class I molecules mediate cell-cell adhesion, showing that CD8 directly binds to MHC class I molecules.
Norment
A M
AM
Department of Microbiology and Immunology, University of California, San Francisco 94143.
Salter
R D
RD
Parham
P
P
Engelhard
V H
VH
Littman
D R
DR
D000945:Antigens, Differentiation, T-Lymphocyte; D001402:B-Lymphocytes / Q000378:metabolism; D002448:Cell Adhesion; D002460:Cell Line; D015395:Histocompatibility Antigens Class I; D006801:Humans
D000945:Antigens, Differentiation, T-Lymphocyte; D015395:Histocompatibility Antigens Class I