title: A nonclassical non-Valpha14Jalpha18 CD1d-restricted (type II) NKT cell is sufficient for down-regulation of tumor immunosurveillance.
abstract: The importance of immunoregulatory T cells has become increasingly apparent. Both CD4+CD25+ T cells and CD1d-restricted NKT cells have been reported to down-regulate tumor immunity in mouse tumor models. However, the relative roles of both T cell populations have rarely been clearly distinguished in the same tumor models. In addition, CD1d-restricted NKT cells have been reported to play a critical role not only in the down-regulation of tumor immunity but also in the promotion of the immunity. However, the explanation for these apparently opposite roles in different tumor models remains unclear. We show that in four mouse tumor models in which CD1d-restricted NKT cells play a role in suppression of tumor immunity, depletion of CD4+CD25+ T cells did not induce enhancement of immunosurveillance. Surprisingly, among the two subpopulations of CD1d-restricted NKT cells, Valpha14Jalpha18+ (type I) and Valpha14Jalpha18- (type II) NKT cells, type I NKT cells were not necessary for the immune suppression. These unexpected results may now resolve the paradox in the role of CD1d-restricted NKT cells in the regulation of tumor immunity, in that type II NKT cells may be sufficient for negative regulation, whereas protection has been found to be mediated by alpha-galactosylceramide-responsive type I NKT cells.
authors.affiliation: Vaccine Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA. terabe@mail.nih.gov
authors.forename: Masaki
authors.initials: M
authors.lastname: Terabe
authors.forename: Jeremy
authors.initials: J
authors.lastname: Swann
authors.forename: Elena
authors.initials: E
authors.lastname: Ambrosino
authors.forename: Pratima
authors.initials: P
authors.lastname: Sinha
authors.forename: Shun
authors.initials: S
authors.lastname: Takaku
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Hayakawa
authors.forename: Dale I
authors.initials: DI
authors.lastname: Godfrey
authors.forename: Suzanne
authors.initials: S
authors.lastname: Ostrand-Rosenberg
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Smyth
authors.forename: Jay A
authors.initials: JA
authors.lastname: Berzofsky
mesh_terms: D000818:Animals; D018949:Antigens, CD1 / Q000378:metabolism; D055610:Antigens, CD1d; D045744:Cell Line, Tumor; D005699:Galactosylceramides / Q000378:metabolism; D007157:Immunologic Surveillance / Q000276:immunology*; D007694:Killer Cells, Natural / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D009369:Neoplasms / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
chemical_list: D018949:Antigens, CD1; D055610:Antigens, CD1d; D005699:Galactosylceramides; C493154:alpha-galactosylceramide