title: Persistent viral infection affects tumorigenicity of a neuroblastoma cell line.
abstract: A mouse neuroblastoma cell line (clone NS20Y) is highly tumorigenic in syngeneic A/J mice. When this clone was persistently infected with measles virus (NS20Y/MS) it failed to grow or form tumors in conventional A/J or nude mice, even when large numbers of cells were inoculated. As doubling time, serum dependence, and anchorage-independent growth on agar did not differ significantly between NS20Y and NS20Y/MS, lack of tumorigenicity of the persistently infected cells is unlikely to be due to an intrinsic property of the cells. NS20Y/MS cells were found to be effectively rejected in athymic nude as well as conventional syngeneic mice. However, injection of mice with either anti-interferon or anti-asialo GM1 serum, both of which have been shown to deplete natural killer (NK) cells in vivo, enabled NS20Y/MS cells to form large tumors. Unexpectedly, treatment of mice with silica also allowed the NS20Y/MS cells to form tumors. Under these conditions, it was shown that silica caused a significant decrease in NK activity as late as 7 days after a single injection. Although NS20Y/MS were not susceptible to NK cell lysis in vitro, the in vivo data suggest that NK cells are in fact the prime mechanism in the rejection of this persistently virus-infected neuroblastoma cell line by athymic and conventional syngeneic mice. The results indicate that NK activity may be greater or more sensitively detected in vivo than in vitro.
mesh_terms: D000818:Animals; D002460:Cell Line; D002471:Cell Transformation, Neoplastic; D002999:Clone Cells; D003602:Cytotoxicity, Immunologic; D006084:Graft Rejection; D007694:Killer Cells, Natural / Q000276:immunology; D008457:Measles / Q000276:immunology*; D051379:Mice; D008815:Mice, Inbred Strains; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D009447:Neuroblastoma / Q000473:pathology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology / Q000637:transplantation; D014184:Transplantation, Homologous