title: Cytotoxic activity of lymphocytes. VII. cellular origin of alpha-lymphotoxin.
abstract: To detect the cellular origins of alpha-lymphotoxin (alpha-LT), we cultured various subpopulations of human blood lymphocytes separated by erythrocyte-rosetting techniques with various mitogens. T cell-enriched subpopulations responded to PHA by increased 3H-thymidine uptake into DNA and large amounts of alpha-LT production. SPL and Con A-Sepharose stimulated DNA synthesis in T cell-enriched cultures if the macrophage content was greater than 1.5%; however, alpha-LT production was not induced by these two mitogens even when reconstituted with 10% macrophages. B and/or null cell-enriched populations severely depleted of T cells (less than 0.7% did not respond to PHA, SPL, or Con A-Sepharose. However, reconstitution to 5 or more percent in E-RFC allowed all three mitogens to stimulate DNA synthesis and alpha-LT production. The LT made by all cell populations 5 and 7 days after stimulation were equally neutralized by a heterologous antiserum to alpha-LT. These results show that human T and B and/or null cells, when appropriately stimulated, can produce alpha-LT.
mesh_terms: D001402:B-Lymphocytes / Q000276:immunology; D002478:Cells, Cultured; D003208:Concanavalin A; D003602:Cytotoxicity, Immunologic; D006801:Humans; D037102:Lectins; D008233:Lymphotoxin-alpha / Q000096:biosynthesis*; D013204:Staphylococcus Phages / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D037102:Lectins; D008233:Lymphotoxin-alpha; D003208:Concanavalin A