Characterization of mature and immature RadLV-induced thymic T-cell lines for tumorigenesis and MHC-class-I gene expression.
Class-I-MHC molecules are divided into class-Ia molecules, which play major roles in recognition of virus-infected cells, graft rejection and immune responses against tumors, and class-Ib molecules, which are less polymorphic and may be responsible for presenting unique classes of peptides. Our report characterizes RadLV-induced thymic T-cell lines that differ both in their tumorigenic potential and in the level of protein for class-Ia and TL genes. The PD1.1 cell line is CD4-CD8+ and expresses relatively high levels of class-I as compared with the CD4+CD8+ PD1.2 cell line. These class-I-expression levels correlate with thymocytes and splenic T cells of the same phenotype, except that normal cells fail to express TL3b. Interferon-treated PD1.2 cells demonstrate significantly lower levels of class-I expression than do interferon-treated PD1.1 cells, and were shown to contain large amounts of degraded class-I mRNA, at least some of which was TL in origin. These RNA products were not detected in PD1.1 cells, suggesting the existence of a mechanism controlling cell-specific and gene-specific mRNA stability. Such RadLV-induced cell lines provide a means for obtaining stage-specific T cells, which can be used for studying the regulation of class-I gene expression during T-cell differentiation, as well as factors that differentially regulate class-Ia and class-Ib expression and are potentially useful for studying T-cell differentiation in general.
Bashi
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O
Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Israel.
Ehrlich
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R
D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000502:physiology* / Q000821:virology*; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000502:physiology* / Q000821:virology*; D002454:Cell Differentiation / Q000502:physiology; D002455:Cell Division / Q000502:physiology; D002460:Cell Line; D015973:Gene Expression Regulation, Leukemic; D015395:Histocompatibility Antigens Class I / Q000235:genetics*; D007372:Interferons / Q000494:pharmacology; D007942:Leukemia, Experimental / Q000235:genetics* / Q000473:pathology / Q000821:virology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D012333:RNA, Messenger / Q000235:genetics; D016721:Radiation Leukemia Virus; D014158:Transcription, Genetic
D015395:Histocompatibility Antigens Class I; D012333:RNA, Messenger; D007372:Interferons