Down-regulation of natural killer cell activity in MoLV leukemogenesis: evidence for tumor-cell-mediated suppression.
The role of natural killer (NK) cells in retrovirus-induced leukemogenesis was studied. These cells which do not require prior sensitization are considered as a part of the body's defense system against tumor development and spread. Neonate BALB/c mice infected with Moloney murine leukemia virus (MoLV) develop leukemia within 3-6 months. The MoLV-infected mice showed a progressive loss of endogenous and augmented NK activity, correlated with the development of the leukemic state. Mixing of spleen cells from tumor-bearing mice with NK-augmented splenocytes resulted in suppression of NK activity. In addition, mixing of T cell lines isolated from MoLV-induced tumors with augmented splenocytes also resulted in the down-regulation of NK cell activity. The present study demonstrates that tumor cells from leukemic organs and leukemic T cell lines can actively suppress NK cell function. It is postulated that after MoLV infection the progression of virus-transformed T cells to a fully developed tumor depends on the ability of these cells to down-regulate NK cell activity and thus escape immune surveillance.
Ofir
R
R
Department of Microbiology and Immunology, Faculty of Health Sciences, Ben Gurion University of the Negev, Beer Sheva, Israel.
Weinstein
Y
Y
Rager-Zisman
B
B
D000818:Animals; D003587:Cytomegalovirus / Q000276:immunology; D007694:Killer Cells, Natural / Q000276:immunology*; D007942:Leukemia, Experimental / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008979:Moloney murine leukemia virus / Q000276:immunology; D011289:Preleukemia / Q000276:immunology*; D013154:Spleen / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology; D014407:Tumor Cells, Cultured / Q000276:immunology