An active T-cell-independent mechanism enhances MHC class I transcription and expression on a mouse T-cell lymphoma in vivo.
The present study focuses on the mechanism underlying changes in H-2 cell surface antigen expression after passage of the in vitro grown YAC-1 lymphoma as an ascites tumor. The increase in cell-surface expression correlated with elevated levels of class I transcripts as revealed by Northern blots. The enhanced H-2 expression was also seen with a cloned YAC-1 line, and not until 2 weeks after in vitro explantation had levels of H-2 decreased to those on the in vitro established YAC-1. Arguing for the necessity of a mature functioning immune system, suckling mice were unable to increase H-2 expression on inoculated lymphoma cells. Also pretreatment with cyclophosphamide or irradiation abolished the capacity of adult mice to increase cell surface H-2 on YAC-1 cells. A functioning T-cell system was not required for H-2 enhancement to occur since athymic nude mice were fully competent. The possible significance of an active T-cell-independent host mechanism which enhances tumor H-2 expression at the transcriptional level is discussed.
D000367:Age Factors; D000818:Animals; D000951:Antigens, Neoplasm / Q000235:genetics*; D000954:Antigens, Surface / Q000276:immunology; D005786:Gene Expression Regulation; D006183:H-2 Antigens / Q000235:genetics*; D007165:Immunosuppression Therapy; D008223:Lymphoma / Q000276:immunology*; D008285:Major Histocompatibility Complex; D051379:Mice; D012333:RNA, Messenger / Q000235:genetics; D013601:T-Lymphocytes / Q000276:immunology*; D018800:Thy-1 Antigens; D014158:Transcription, Genetic
D000951:Antigens, Neoplasm; D000954:Antigens, Surface; D006183:H-2 Antigens; D012333:RNA, Messenger; D018800:Thy-1 Antigens