title: Role of the Ly 1 antigen in interleukin 1-induced thymocyte activation.
abstract: Interleukin 1 (IL 1), but not IL 2-induced thymocyte proliferation was augmented by monoclonal antibodies (mAb) against the Ly 1 antigen. The anti-Ly 1 mAb could also co-stimulate thymocytes with phytohemagglutinin (PHA) alone, mimicking the effect of IL 1. Moreover, overnight culture with PHA of thymocytes, but not of spleen T lymphocytes led to selectively enhanced expression of the Ly 1 antigen on the cell surface. Similar data were generated at the clonal level. Thus, a thymocyte hybridoma (22A6) could be stimulated to release IL 2 in response to PHA plus IL 1, but also to PHA plus anti-Ly 1 mAb. In addition, 22A6 exhibited enhanced cell surface expression of the Ly 1 antigen after overnight culture with PHA. These data suggest a critical role for the Ly 1 antigen in thymocyte proliferation, perhaps by serving as an IL 1-receptor.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000950:Antigens, Ly / Q000276:immunology*; D001681:Biological Assay; D002478:Cells, Cultured; D006825:Hybridomas / Q000276:immunology*; D007375:Interleukin-1 / Q000032:analysis / Q000276:immunology*; D007376:Interleukin-2 / Q000096:biosynthesis; D007518:Isoantibodies / Q000276:immunology; D008213:Lymphocyte Activation; D051379:Mice; D008815:Mice, Inbred Strains; D010835:Phytohemagglutinins / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000950:Antigens, Ly; D007375:Interleukin-1; D007376:Interleukin-2; D007518:Isoantibodies; D010835:Phytohemagglutinins