title: Mechanisms of activation and suppression in rat Nb 2 lymphoma cells: a model for interactions between prolactin and the immune system.
abstract: Rat Nb 2 lymphoma cells have been widely used to bioassay human growth hormone and many species of prolactin. Because their morphologic characterization suggests a T-cell lineage, Nb 2 cells were examined for their response to the T-cell mitogens concanavalin A, pokeweed mitogen, and phytohemagglutinin P. As expected, a dose-response to rat prolactin was observed; however, attempts to induce proliferation using the conventional T-cell mitogens failed at concentrations normally stimulatory for rat primary lymphocytes. Moreover, when Nb 2 cells were simultaneously incubated with lectin plus a suboptimal concentration of prolactin, a dose-dependent suppression of the stimulatory effects of prolactin was observed with phytohemagglutinin P and pokeweed mitogen, although not with concanavalin A. Culture medium of prolactin-stimulated Nb 2 cells also contained a factor which inhibited normal rat lymphocyte activation by concanavalin A. The factor did not block induction of the IL-2 receptor and proliferation of IL-2-dependent CTLL-2 cells could be restored by exogenous IL-2. Because Nb 2 cells evolved from a lactogen-dependent lymph node tumor, these results may have implications for further understanding the role of pituitary hormones, particularly prolactin, in the immune response to hormone-dependent tumor progression.
authors.affiliation: Department of Molecular and Cell Biology, Pennsylvania State University, University Park 16802, USA.
authors.forename: L G
authors.initials: LG
authors.lastname: Bates
authors.forename: D S
authors.initials: DS
authors.lastname: Grove
authors.forename: A M
authors.initials: AM
authors.lastname: Mastro
mesh_terms: D000818:Animals; D002455:Cell Division / Q000187:drug effects; D003208:Concanavalin A / Q000494:pharmacology; D006801:Humans; D007376:Interleukin-2 / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000187:drug effects; D008223:Lymphoma / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D008934:Mitogens / Q000494:pharmacology; D011388:Prolactin / Q000494:pharmacology*; D051381:Rats; D013154:Spleen / Q000166:cytology / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D007376:Interleukin-2; D008934:Mitogens; D003208:Concanavalin A; D011388:Prolactin