title: Clonal expansion of T cells: a cytotoxic T-cell response in vivo that involves precursor cell proliferation.
abstract: The response of peritoneal exudate lymphocytes to allogeneic tumor cells was used to determine whether the in vivo generation of cytotoxic T cells (CTL) involved the proliferation of precursor cells. Ten days post-injection, both cytotoxic activity and the formation of conjugates between lymphocytes and target cells were shown to be specific for the immunizing tumor alloantigens and to be effected by Ly-2+ cells. A cell-sorting-based procedure was developed to isolate specific conjugates between red-fluorescence-tagged CTL and blue-fluorescence-tagged tumor target cells. When [3H]thymidine was administered during the response, almost all isolated conjugate-forming CTL were 3H-labeled on autoradiography. Thus, the CTL were clearly products of dividing cells, a result that contradicts published data. Reassessment of a previously studied system, which suggested that CTL were not products of cell division, indicated that in that system many of the conjugate-forming cytotoxic cells studied were Ly-2- and nonspecific, and thus perhaps not T cells. We conclude that the clonal selection model is applicable to at least one in vivo T-cell response.
mesh_terms: D000818:Animals; D002455:Cell Division; D002460:Cell Line; D002999:Clone Cells; D003602:Cytotoxicity, Immunologic; D004261:DNA Replication; D008213:Lymphocyte Activation; D008223:Lymphoma / Q000276:immunology; D012515:Mast-Cell Sarcoma / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D010641:Phenotype; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D013936:Thymidine / Q000378:metabolism
chemical_list: D013936:Thymidine