title: Identification of human lymphocyte-derived lymphotoxins with binding and cell-lytic activity on NK-sensitive cell lines in vitro.
abstract: Supernatants obtained from lectin-restimulated, preactivated, human peripheral blood lymphocytes rapidly released (5-24 hr) high levels of lymphotoxin (LT) activity in vitro. Peripheral blood lymphocytes were preactivated by coculturing with either fetal calf serum or with allogeneic continuous B-cell lines (LCCL) which were treated with mitomycin C. These supernatants contained a population of L-929 cell-lytic LT forms which also selectively bind to the NK-sensitive K-562 cell. However, lytic LT forms for L-929 cells from cPBL and LCCL cultures did not bind to the NK-sensitive MOLT-4 or NK-resistant Raji cells. Additional studies reveal these supernatants contain a second set of LT forms which have cell-binding and cell-lytic activity detectable on MOLT-4 and K-562 cells in a 12 to 18 hr 51Cr-release assay. Cell-lytic form(s) for the MOLT-4 and K-562 cells were not stable for more than a week at -20 degrees C. These findings indicate that materials with LT activity are heterogeneous with respect to their capacity to recognize common and discrete cell-surface components on different types of target cells in vitro.
mesh_terms: D000818:Animals; D000918:Antibody Specificity; D001666:Binding Sites, Antibody; D002051:Burkitt Lymphoma / Q000276:immunology / Q000473:pathology; D002460:Cell Line; D006801:Humans; D007694:Killer Cells, Natural / Q000166:cytology*; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000145:classification; D008233:Lymphotoxin-alpha / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D008937:Mitomycins / Q000494:pharmacology
chemical_list: D008233:Lymphotoxin-alpha; D008937:Mitomycins