title: Cell surface expression of cytotoxic T lymphocyte-defined, AKR/Gross leukemia virus-associated tumor antigens by normal AKR.H-2b splenic B cells.
abstract: We previously described a system in which H-2Kb-restricted C57BL/6 (B6) cytotoxic T lymphocytes (CTL) could be raised that were specific for tumors, such as the thymic lymphoma AKR.H-2b SL1, that were induced by endogenous AKR/Gross murine leukemia virus and that expressed the Gross cell surface antigen. In this study, certain normal lymphoid cells from AKR.H-2b mice were also found to express target antigens defined by such anti-AKR/Gross virus CTL. AKR.H-2b spleen, but surprisingly not thymus, cells stimulated the production of anti-AKR/Gross virus CTL when employed at either the in vivo priming phase or the in vitro restimulation phase of anti-viral CTL induction. This selective stimulation by spleen vs thymus cells was not dependent on the age of the mice over the range (3 to 28 wk) tested. Both AKR.H-2b spleen and thymus cells, however, were able to stimulate the generation of H-2-restricted B6 anti-AKR minor histocompatibility (H) antigen-specific CTL. Thus, AKR.H-2b spleen cells appeared to display the same sets (minor H and virus-associated) of cell surface antigens recognized by CTL as the AKR.H-2b SL1 tumor, whereas AKR.H-2b thymocytes were selectively missing the virus-associated target antigens, a situation analogous to that of cl. 18-5, a variant subclone of AKR.H-2b SL1 insusceptible to anti-AKR/Gross virus CTL. Like AKR.H-2b thymocytes, neither AKR spleen cells or thymocytes nor B6.GIX + thymocytes were able to stimulate the generation of anti-AKR/Gross virus CTL from primed B6 responder cell populations. In contrast, both T cell-enriched and B cell-enriched preparations derived from AKR.H-2b spleen cells were able to stimulate at the in vitro phase of induction, although B cell-enriched preparations were considerably more efficient. The discordant results obtained with AKR.H-2b spleen cells vs thymocytes were confirmed and extended in experiments in which these cells were employed as target cells to directly assess the cell surface expression of virus-associated, CTL-defined antigens. Thus, AKR.H-2b spleen cells, but not thymocytes, were recognized by anti-AKR/Gross virus CTL when fresh normal cells were tested as unlabeled competitive inhibitors, or when mitogen blasts were tested as labeled targets. Fresh or lipopolysaccharide-stimulated B cell-enriched spleen cells were as efficiently recognized as unseparated spleen cell preparations. Unexpectedly, fresh or Lens culinaris hemagglutinin-stimulated T cell-enriched spleen cell preparations, although susceptible to anti-minor H CTL, were almost as poor as targets for anti-viral CTL as were thymocytes. Together, these results demonstrate the H-2-restricted expression of CTL-defined, endogenous, AKR/Gross virus-associated target antigens by normal AKR.H-2b splenic B cells.(ABSTRACT TRUNCATED AT 400 WORDS)
mesh_terms: D000406:AKR murine leukemia virus / Q000276:immunology; D000375:Aging; D000818:Animals; D000951:Antigens, Neoplasm / Q000032:analysis*; D000956:Antigens, Viral / Q000032:analysis; D001402:B-Lymphocytes / Q000276:immunology*; D002472:Cell Transformation, Viral; D006183:H-2 Antigens / Q000235:genetics / Q000276:immunology; D007942:Leukemia, Experimental / Q000276:immunology*; D008213:Lymphocyte Activation; D051379:Mice; D008806:Mice, Inbred AKR; D008810:Mice, Inbred C57BL; D013154:Spleen / Q000166:cytology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology* / Q000502:physiology; D013950:Thymus Gland / Q000166:cytology
chemical_list: D000951:Antigens, Neoplasm; D000956:Antigens, Viral; D006183:H-2 Antigens