Interactions between CD8alphabeta and the TCRalphabeta/CD3-receptor complex.
CD8+ T cells recognize antigenic peptides bound to major histocompatibility complex (MHC) class I molecules on normal antigen-presenting cells (APC), as well as on virus-infected cells or tumour cells (pMHC). At least two receptor types participate in recognition of these complexes: T-cell receptor (TCR) alphabeta heterodimers and CD8alphabeta molecules. The former molecules react with antigenic peptide and variable regions of MHC class I molecules, whereas the latter molecules react with constant alpha3 regions of MHC class I molecules. As the avidity of both receptor-MHC interactions is low, it is believed that TCRalphabeta and CD8alphabeta heterodimers collaborate in T-cell recognition. We have established a TCR/CD3-CD8 capture ELISA, which can measure the interaction of pMHC with CD8alphabeta molecules and with TCR/CD3 complexes. The major findings are: (1) TCR/CD3 complexes derived from in vitro activated T cells and captured by anti-CD3 MoAb, do bind specific pMHC and (2) CD8+ T cells express at least three forms of CD8alphabeta molecules: single CD8alphabeta, CD3-CD8 and TCR/CD3-CD8 complexes. Only the latter complexes are associated with CD3zeta homodimers, and the quantity of TCR/CD3-CD8 complexes relative to total CD8alphabeta molecules appears to increase and to be selected into sucrose-gradient microdomains as a function of TCRalphabeta-mediated T-cell activation.
Rubin
B
B
Centre de Recherche en Pharmacologie-Santé, UMR 2587 CNRS-Pierre Fabre, 3 rue des Satellites, 31400 Toulouse, France. bent.rubin@istmt.cnrs.fr
Riond
J
J
Leghait
J
J
Gairin
J E
JE
D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry*; D016827:CD8 Antigens / Q000378:metabolism*; D045744:Cell Line, Tumor; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D006801:Humans; D008213:Lymphocyte Activation; D008285:Major Histocompatibility Complex / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D017260:Receptor-CD3 Complex, Antigen, T-Cell / Q000276:immunology*; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000378:metabolism*; D013601:T-Lymphocytes / Q000276:immunology
D000911:Antibodies, Monoclonal; D016827:CD8 Antigens; D017260:Receptor-CD3 Complex, Antigen, T-Cell; D016693:Receptors, Antigen, T-Cell, alpha-beta