Anti-Qa-2-induced T cell activation. The parameters of activation, the definition of mitogenic and nonmitogenic antibodies, and the differential effects on CD4+ vs CD8+ T cells.
The MHC Ag Qa-2 is a glycolipid anchored class I molecule expressed at high levels on all peripheral T lymphocytes. In this study we found that anti-Qa-2 antibodies could stimulate the proliferation of murine T cells in vitro. Anti-Qa-2-induced proliferation required secondary cross-linking with anti-Ig antibody and the presence of PMA. Only Qa-2+ strains could be induced to proliferate by anti-Qa-2 antibody, but under the conditions employed, anti-CD3 could induce proliferation in Qa-2+ and Qa-2-strains. Interestingly, only anti-Qa-2 reagents directed against the alpha 3 domain of the Qa-2 class I molecule were effective in inducing proliferation. Furthermore, unlike purified CD4+ cells, purified CD8+ cells were unable to be stimulated by the anti-Qa-2 antibodies. These results lead to the inclusion of Qa-2 in a group of physiologically relevant, glycolipid-anchored, cell-surface molecules, mobilization of which can generate signals that initiate the proliferation of T cells. Such molecules may play a secondary role in cellular activation after the primary engagement of the TCR.
Hahn
A B
AB
Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205.
Soloski
M J
MJ
D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology*; D000954:Antigens, Surface / Q000276:immunology; D000961:Antilymphocyte Serum / Q000502:physiology*; D016827:CD8 Antigens; D015395:Histocompatibility Antigens Class I / Q000276:immunology*; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D008934:Mitogens / Q000502:physiology*; D010641:Phenotype; D013045:Species Specificity; D013601:T-Lymphocytes / Q000145:classification / Q000276:immunology*
D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D000961:Antilymphocyte Serum; D016827:CD8 Antigens; D015395:Histocompatibility Antigens Class I; D008934:Mitogens; C032907:Q surface antigens