title: NK activity in neuroblastoma bearing mice: in vivo versus in vitro propagated tumor variants.
abstract: Two days after inoculation of A/J mice with in vivo propagated C1300 neuroblastoma (NB) cells, a 4-5 fold increase of the splenic natural killer (NK) activity is noticed. A similar rise of NK activity is also displayed by the host lymph node, bone marrow and peritoneal cells, reflecting a general stimulation of NK cells. These effector cells only lyse classical NK target cells. They are of low specific gravity, nylon wool non-adherent and insensitive to anti-Thy treatment, suggesting that they are indeed NK cells. In spite of the ability of in vivo maintained NB cells to increase the NK activity, they are not lysed by NK cells, nor do they have NK-recognizable target structures as demonstrated by competition studies. In contrast with the previously mentioned experiments, NB cells that have been cultured in vitro for at least one week, do not increase the NK activity. During further growth of both tumor variants, the NK activity gradually decreases. In vivo experiments revealed that the presence of a large NB tumor load exerts a negative effect on the induction of active NK effectors. This effect is not due to the intervention of splenic suppressor cells.
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D003602:Cytotoxicity, Immunologic; D004306:Dose-Response Relationship, Immunologic; D007111:Immunity, Cellular; D007113:Immunity, Innate; D007694:Killer Cells, Natural / Q000276:immunology*; D008221:Lymphoid Tissue / Q000166:cytology; D051379:Mice; D009447:Neuroblastoma / Q000276:immunology*; D013154:Spleen / Q000276:immunology