title: Cell cycle-dependent expression of antigen-binding and I-J-bearing molecules on suppressor T cell hybridomas.
abstract: The I-J and antigen-binding chains with constant region determinant (Ct) that compose an antigen-specific suppressor T cell factor were found on the surface of suppressor T cell hybridomas, serologically and morphologically demonstrated by a fluorescence-activated cell sorter (FACS) and immunoelectron microscopic analyses. Moreover, the surface expression of the I-J and Ct-bearing chains fluctuating with the same kinetics depended entirely upon the cell cycle. The maximum expression of these two chains was observed in the early stage of the M phase, and the minimum in the S phase. Similarly, the magnitude of the suppressor activity was maximal in the late stage of the M phase, and was minimal in the S phase. The results therefore demonstrated that there exists good correlation between the cell surface expression of the I-J and Ct-bearing chains and the magnitude of the suppressor activity produced. The antigen recognition units on suppressor T cell hybridomas have serologically and morphologically been characterized by using radiolabeled antigens or monoclonal antibodies against the I-J or Ct on the antigen-binding molecule. Cell-binding assay and radioautographic analysis demonstrated that the suppressor T cell hybridoma possesses the capacity to bind native antigen in an antigen-specific fashion as does the hybridoma-derived, antigen-specific suppressor factor composed of the I-J and the Ct-bearing chains, indicating that the recognition unit on the cell surface is composed of a structure similar to the factor.
mesh_terms: D000818:Animals; D002453:Cell Cycle; D000939:Epitopes / Q000032:analysis; D005434:Flow Cytometry; D006433:Hemocyanins / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000032:analysis*; D006825:Hybridomas / Q000276:immunology* / Q000648:ultrastructure; D007127:Immunoglobulin Constant Regions / Q000276:immunology; D051379:Mice; D008805:Mice, Inbred A; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D011948:Receptors, Antigen, T-Cell / Q000032:analysis*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
chemical_list: D000939:Epitopes; D000949:Histocompatibility Antigens Class II; D007127:Immunoglobulin Constant Regions; D011948:Receptors, Antigen, T-Cell; D006433:Hemocyanins