CD8 is involved in both class I- and class II-induced proliferation of a cytolytic T-cell clone with dual specificity for HLA-B27 and HLA-DR2 antigens.
A CD3+ CD4- CD8+ cytolytic T-lymphocyte (CTL) clone, CTL 47, could be induced to proliferate in the presence of exogenous interleukin 2 by either HLA-B27.1+ or HLA-DR2+ cells. B27.1-induced proliferation was strongly and equally inhibited by an anti-B27 and by an anti-CD8 monoclonal antibody (MoAb). DR2-induced proliferation was inhibited by the same anti-CD8 MoAb less efficiently and with a different time course than anti-class II blocking, only being significant when the antibody was added ab initio or very early during the assay. These results indicate that CD8 is essential for class I-induced proliferation but that it also enhances class II-induced stimulation of this CTL clone. It is proposed that the necessary role of CD8 in class I-induced proliferation is related to its interaction with the same class I molecule bound by the T-cell receptor. The accessory role in class II-induced proliferation would be due to an additive effect on the avidity of cell adhesion, resulting from interaction of CD8 with the class I antigens on the stimulator cell, or perhaps to a regulatory role of CD8 as a transducer of early signals for T-cell activation.
Aparicio
P
P
Department of Immunology, Fundación Jiménez Díaz (C.S.I.C.), Madrid, Spain.
López de Castro
J A
JA
D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology*; D016827:CD8 Antigens; D002455:Cell Division; D002478:Cells, Cultured; D015235:HLA-B Antigens / Q000276:immunology*; D006684:HLA-DR Antigens / Q000276:immunology*; D015395:Histocompatibility Antigens Class I / Q000276:immunology*; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology; D013997:Time Factors
D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D016827:CD8 Antigens; D015235:HLA-B Antigens; D006684:HLA-DR Antigens; D015395:Histocompatibility Antigens Class I; D000949:Histocompatibility Antigens Class II