Abstract
The role of mouse liver NK1.1 Ag(+) T (NKT) cells in the antitumor effect of alpha-galactosylceramide (alpha-GalCer) has been unclear. We now show that, whereas alpha-GalCer increased the serum IFN-gamma concentration and alanine aminotransferase activity in NK cell-depleted C57BL/6 (B6) mice and B6-beige/beige mice similarly to its effects in control B6 mice, its enhancement of the antitumor cytotoxicity of liver mononuclear cells (MNCs) was abrogated. Depletion of both NK and NKT cells in B6 mice reduced all these effects of alpha-GALCER: Injection of Abs to IFN-gamma also inhibited the alpha-GalCer-induced increase in antitumor cytotoxicity of MNCS: alpha-GalCer induced the expression of Fas ligand on NKT cells in the liver of B6 mice. Whereas alpha-GalCer did not increase serum alanine aminotransferase activity in B6-lpr/lpr mice and B6-gld/gld mice, it increased the antitumor cytotoxicity of liver MNCS: The alpha-GalCer-induced increase in survival rate apparent in B6 mice injected intrasplenically with B16 tumor cells was abrogated in beige/beige mice, NK cell-depleted B6 mice, and B6 mice treated with Abs to IFN-gamma. Depletion of CD8(+) T cells did not affect the alpha-GalCer-induced antitumor cytotoxicity of liver MNCs but reduced the effect of alpha-GalCer on the survival of B6 mice. Thus, IFN-gamma produced by alpha-GalCer-activated NKT cells increases both the innate antitumor cytotoxicity of NK cells and the adaptive antitumor response of CD8(+) T cells, with consequent inhibition of tumor metastasis to the liver. Moreover, NKT cells mediate alpha-GalCer-induced hepatocyte injury through Fas-Fas ligand signaling.
MeSH terms
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Alanine Transaminase / blood
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Animals
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Antibodies, Monoclonal / administration & dosage
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Antigens / immunology
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Antigens, Ly
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Antigens, Surface
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Antineoplastic Agents / administration & dosage*
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Antineoplastic Agents / antagonists & inhibitors
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Antineoplastic Agents / toxicity
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Cytotoxicity, Immunologic / genetics
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Enzyme Activation / immunology
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Fas Ligand Protein
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G(M1) Ganglioside / immunology
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Galactosylceramides / administration & dosage*
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Galactosylceramides / antagonists & inhibitors
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Galactosylceramides / toxicity
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Growth Inhibitors / administration & dosage
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Growth Inhibitors / toxicity
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Growth Substances / administration & dosage
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Growth Substances / toxicity
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Hepatocytes / immunology*
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Hepatocytes / pathology*
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Immune Sera / administration & dosage
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Injections, Intralymphatic
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Injections, Intravenous
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Interferon-gamma / antagonists & inhibitors
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Interferon-gamma / blood
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Interferon-gamma / immunology
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Killer Cells, Natural / immunology
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Killer Cells, Natural / metabolism
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Killer Cells, Natural / pathology
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Lectins, C-Type
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Leukocytes, Mononuclear / immunology
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Ligands
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Liver Neoplasms, Experimental / genetics
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Liver Neoplasms, Experimental / pathology
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Liver Neoplasms, Experimental / prevention & control*
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Liver Neoplasms, Experimental / secondary*
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Lymphocyte Count
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Lymphocyte Depletion
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Male
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Melanoma, Experimental / immunology
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Melanoma, Experimental / mortality
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Membrane Glycoproteins / biosynthesis
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Mice
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Mice, Inbred C57BL
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Mice, Inbred MRL lpr
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Mice, Mutant Strains
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NK Cell Lectin-Like Receptor Subfamily B
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Proteins / immunology
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Spleen
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Survival Analysis
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T-Lymphocyte Subsets / immunology
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T-Lymphocyte Subsets / metabolism
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T-Lymphocyte Subsets / pathology
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Tumor Cells, Cultured / transplantation
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fas Receptor / metabolism
Substances
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Antibodies, Monoclonal
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Antigens
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Antigens, Ly
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Antigens, Surface
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Antineoplastic Agents
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Fas Ligand Protein
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Fasl protein, mouse
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Galactosylceramides
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Growth Inhibitors
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Growth Substances
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Immune Sera
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Klrb1c protein, mouse
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Lectins, C-Type
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Ligands
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Membrane Glycoproteins
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NK Cell Lectin-Like Receptor Subfamily B
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Proteins
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fas Receptor
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G(M1) Ganglioside
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asialo GM1 ganglioside
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Interferon-gamma
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Alanine Transaminase