title: Delicate balance among three types of T cells in concurrent regulation of tumor immunity.
abstract: The nature of the regulatory cell types that dominate in any given tumor is not understood at present. Here, we addressed this question for regulatory T cells (Treg) and type II natural killer T (NKT) cells in syngeneic models of colorectal and renal cancer. In mice with both type I and II NKT cells, or in mice with neither type of NKT cell, Treg depletion was sufficient to protect against tumor outgrowth. Surprisingly, in mice lacking only type I NKT cells, Treg blockade was insufficient for protection. Thus, we hypothesized that type II NKT cells may be neutralized by type I NKT cells, leaving Tregs as the primary suppressor, whereas in mice lacking type I NKT cells, unopposed type II NKT cells could suppress tumor immunity even when Tregs were blocked. We confirmed this hypothesis in 3 ways by reconstituting type I NKT cells as well as selectively blocking or activating type II NKT cells with antibody or the agonist sulfatide, respectively. In this manner, we showed that blockade of both type II NKT cells and Tregs is necessary to abrogate suppression of tumor immunity, but a third cell, the type I NKT cell, determines the balance between these regulatory mechanisms. As patients with cancer often have deficient type I NKT cell function, managing this delicate balance among 3 T-cell subsets may be critical for the success of immunotherapy for human cancer.
authors: Vaccine Branch and Biostatistics and Data Management Section, Center for Cancer Research, National Cancer Institute/NIH, Bethesda, MD 20892, USA.
authors: Liat
authors: L
authors: Izhak
authors: Elena
authors: E
authors: Ambrosino
authors: Shingo
authors: S
authors: Kato
authors: Stanley T
authors: ST
authors: Parish
authors: Jessica J
authors: JJ
authors: O'Konek
authors: Hannah
authors: H
authors: Weber
authors: Zheng
authors: Z
authors: Xia
authors: David
authors: D
authors: Venzon
authors: Jay A
authors: JA
authors: Berzofsky
authors: Masaki
authors: M
authors: Terabe
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D015179:Colorectal Neoplasms / Q000276:immunology*; D005260:Female; D007680:Kidney Neoplasms / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D055611:Natural Killer T-Cells / Q000276:immunology*; D013433:Sulfoglycosphingolipids / Q000494:pharmacology; D016176:T-Lymphocyte Subsets / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
chemical_list: D013433:Sulfoglycosphingolipids