CD4(+) T cells eliminate MHC class II-negative cancer cells in vivo by indirect effects of IFN-gamma.
CD4(+) T cells can eliminate tumor cells in vivo in the absence of CD8(+) T cells. We have CD4(+) T cells specific for a MHC class II-restricted, tumor-specific peptide derived from a mutant ribosomal protein expressed by the UV light-induced tumor 6132A-PRO. By using neutralizing mAb specific for murine IFN-gamma and adoptive transfer of CD4(+) T cells into severe combined immunodeficient mice, we show that anti-IFN-gamma treatment abolishes the CD4(+) T cell-mediated rejection of the tumor cells in vivo. The tumor cells were MHC class II negative, and IFN-gamma did not induce MHC class II expression in vitro. Therefore, the tumor-specific antigenic peptide must be presented by host cells and not the tumor cells. Tumor cells transduced to secrete IFN-gamma had a markedly reduced growth rate in severe combined immunodeficient mice, but IFN-gamma did not inhibit the growth of the tumor cells in vitro. Furthermore, tumor cells stably expressing a dominant-negative truncated form of the murine IFN-gamma receptor alpha chain, and therefore insensitive to IFN-gamma, nevertheless were rejected by the adoptively transferred CD4(+) T cells. Thus, host cells, and not tumor cells, seem to be the target of IFN-gamma. Together, these results show that CD4(+) T cells can eliminate IFN-gamma-insensitive, MHC class II-negative cancer cells by an indirect mechanism that depends on IFN-gamma.
Department of Pathology, The University of Chicago, 5841 South Maryland Avenue, Chicago, IL 60637, USA.
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D
Mumberg
P A
PA
Monach
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S
Wanderling
M
M
Philip
A Y
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Toledano
R D
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Schreiber
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H
Schreiber
D000595:Amino Acid Sequence; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002455:Cell Division; D002478:Cells, Cultured; D005434:Flow Cytometry; D005805:Genes, MHC Class I / Q000276:immunology; D006084:Graft Rejection / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000032:analysis* / Q000235:genetics; D007371:Interferon-gamma / Q000378:metabolism*; D008198:Lymph Nodes / Q000276:immunology; D051379:Mice; D008819:Mice, Nude; D016513:Mice, SCID; D008969:Molecular Sequence Data; D009368:Neoplasm Transplantation; D010455:Peptides / Q000276:immunology; D014162:Transfection; D014407:Tumor Cells, Cultured / Q000276:immunology*
D000949:Histocompatibility Antigens Class II; D010455:Peptides; D007371:Interferon-gamma