title: Secretion of a suppressor cell inducing factor by an interleukin-3 dependent cell line with natural cytotoxic activity.
abstract: This report describes the morphology, surface markers, growth requirements, and functional activity of the M1-A5 cell line, which was established by the limiting dilution of spleen cells from a mouse bearing a large methylcholanthrene-induced fibrosarcoma. The M1-A5 cells share many of the morphological features of large granular lymphocytes and, in addition, express asialo GM1 and Ly-5 surface markers which are commonly found on natural killer cells (NK) cells. There is no expression of T-cell differentiation antigens, surface immunoglobulin, or the granulocyte/macrophage marker, MAC-1. M1-A5 cells are dependent on exogenous growth factor(s) for survival and will proliferate if cultured in interleukin 3 (IL-3), but not in interleukin 1 (IL-1), interleukin 2 (IL-2), or granulocyte/macrophage colony stimulating factor (GM-CSF). In addition, the M1-A5 cells do not absorb IL-2. Despite their morphology and surface characteristics, the M1-A5 cells do not lyse NK targets such as YAC-1 and RLM1 in 4- or 18-hr cytotoxic assays but do lyse the natural cytotoxic (NC) susceptible target, WEHI-164, and to a very small extent, the M-1 fibrosarcoma cells, in an 18-hr assay. Thus they exhibit NC-like cytotoxic activity. In addition, the M1-A5 cells secrete a small molecular weight factor which activates suppressor cells capable of inhibiting antibody synthesis by cocultured syngeneic spleen cells.
mesh_terms: D000818:Animals; D000954:Antigens, Surface / Q000032:analysis; D002453:Cell Cycle / Q000187:drug effects; D002460:Cell Line; D003602:Cytotoxicity, Immunologic; D006133:Growth Substances / Q000494:pharmacology; D007113:Immunity, Innate; D007376:Interleukin-2 / Q000502:physiology; D007377:Interleukin-3; D007694:Killer Cells, Natural / Q000276:immunology*; D008222:Lymphokines / Q000502:physiology*; D008297:Male; D051379:Mice; D008811:Mice, Inbred DBA; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
chemical_list: D000954:Antigens, Surface; D006133:Growth Substances; D007376:Interleukin-2; D007377:Interleukin-3; D008222:Lymphokines