title: Combination treatment with IL-2 and anti-IL-2 mAbs reduces tumor metastasis via NK cell activation.
abstract: Combination treatment consisting of IL-2 together with anti-IL-2 mAbs results in markedly larger increases in the numbers of CD8(+) T cells, dendritic cells (DCs) and NK cells in vivo compared with the results observed with injections of IL-2 or the antibodies alone. We previously showed that this combination treatment overcomes the problems associated with the short half-life of IL-2 in vivo. Importantly, the combination treatment but not IL-2 or the anti-IL-2 mAbs alone protected the mice against tumor metastases in the lungs. Here we have investigated which cell types are responsible for this protective immunity against tumors. We analyzed tumor metastases in mice that were depleted of DCs, CD8(+) T cells or NK cells. DC-deficient, diphtheria toxin receptor-expressing mice injected with diphtheria toxin as well as B cell- and T cell-deficient RAG-2-knockout mice were protected against tumors after they were administered the combination treatment. On the other hand, mice that were depleted of NK cells using anti-asialo-GM1 antibodies did not exhibit the anti-tumor activity after treatment with IL-2 combined with anti-IL-2 mAbs. Thus, these data demonstrate that NK cells, but not DCs, or CD8(+) T cells mediate the anti-tumor effect induced by this combination treatment. Therefore, combining neutralizing anti-IL-2 mAbs with IL-2 may be clinically useful to effectively enhance IL-2-mediated NK cell activities.
authors.affiliation: Laboratory of Developmental Immunology, Graduate School of Frontier Biosciences and Graduate School of Medicine, Osaka University, Osaka, Japan.
authors.forename: Gui-Hua
authors.initials: GH
authors.lastname: Jin
authors.forename: Toshio
authors.initials: T
authors.lastname: Hirano
authors.forename: Masaaki
authors.initials: M
authors.lastname: Murakami
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage*; D018414:CD8-Positive T-Lymphocytes / Q000187:drug effects / Q000276:immunology* / Q000473:pathology; D003713:Dendritic Cells / Q000187:drug effects / Q000276:immunology* / Q000473:pathology; D005677:G(M1) Ganglioside / Q000276:immunology; D066257:Heparin-binding EGF-like Growth Factor; D007111:Immunity, Cellular; D007167:Immunotherapy; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000276:immunology; D007376:Interleukin-2 / Q000037:antagonists & inhibitors / Q000276:immunology* / Q000494:pharmacology; D007694:Killer Cells, Natural / Q000187:drug effects / Q000276:immunology* / Q000473:pathology; D008175:Lung Neoplasms / Q000276:immunology* / Q000473:pathology*; D008546:Melanoma, Experimental / Q000276:immunology* / Q000517:prevention & control / Q000556:secondary*; D051379:Mice; D009362:Neoplasm Metastasis; D009368:Neoplasm Transplantation
chemical_list: C587884:Hbegf protein, mouse; D066257:Heparin-binding EGF-like Growth Factor; D036341:Intercellular Signaling Peptides and Proteins; D007376:Interleukin-2; D005677:G(M1) Ganglioside; C018835:asialo GM1 ganglioside