title: Activation of murine T lymphocytes with monoclonal antibodies: detection on Lyt-2+ cells of an antigen not associated with the T cell receptor complex but involved in T cell activation.
abstract: A new T cell molecule defined by the mAb 143-4-2 has been identified that is involved in T cell activation. The expression of the 143-4-2-defined epitope is linked to the previously characterized Ly-6 locus and restricted to bone marrow cells and to a subset of peripheral Lyt-2+ cells. In comparison to other anti-Ly-6.2 mAb, the 143-4-2 mAb appears to be directed at an allogeneic determinant of the Ly-6.2C molecule. The anti-Ly-6.2C antibody can promote the lysis of antigen-non-bearing target cells by alloreactive CTL clones, and in the presence of cofactors (PMA or IL 2) induces a subset of Lyt-2+ cells to proliferate, perhaps through an autocrine pathway. Although the antibody described has antigen-like effects as described for anti-TcR complex reagents, studies performed with a recently derived anti-murine T3 mAb suggest that the Ly-6.2C molecule is not associated on the cell surface with components of the TcR complex. Nevertheless, cell surface expression of the TcR complex is required for optimal triggering of T cells via the Ly-6.2C molecule. Because Ly-6.2C determinants are expressed in bone marrow and not in the thymus, the possibility is considered that expression of this molecule identifies a distinct subset of extrathymically derived T cells.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D000937:Antigen-Antibody Reactions; D000950:Antigens, Ly / Q000502:physiology*; D002448:Cell Adhesion; D003602:Cytotoxicity, Immunologic; D005434:Flow Cytometry; D008213:Lymphocyte Activation; D046911:Macromolecular Substances; D051379:Mice; D011948:Receptors, Antigen, T-Cell / Q000502:physiology; D013601:T-Lymphocytes / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D000950:Antigens, Ly; D046911:Macromolecular Substances; D011948:Receptors, Antigen, T-Cell