NKT cells in immunoregulation of tumor immunity: a new immunoregulatory axis.
CD1d-restricted natural killer T (NKT) cells have at least two subsets: type I, semi-invariant TCRalpha chain-expressing (Valpha14Jalpha18 in mice, Valpha24Jalpha18 in humans), and type II, variable TCRalpha chain-expressing. The protective role of NKT cells in tumor immunosurveillance and immunity has been well documented but paradoxically, there are also studies ascribing a suppressive role to these cells. Recent studies have resolved this paradox by revealing distinct roles for the two types of NKT cells, whereby type I NKT cells enhance anti-tumor responses and type II NKT cells suppress these responses. The finding of cross-regulation between the two types of NKT cells suggests a new immunoregulatory axis. Consideration of the cross-talk of NKT cells along with the well-defined suppression by regulatory T cells could provide new insights into cancer immunotherapy.
Terabe
Masaki
M
Vaccine Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20814, USA. terabe@mail.nih.gov
Berzofsky
Jay A
JA
D000818:Animals; D018949:Antigens, CD1 / Q000276:immunology; D006801:Humans; D007108:Immune Tolerance; D007694:Killer Cells, Natural / Q000276:immunology* / Q000502:physiology*; D009369:Neoplasms / Q000276:immunology*; D011971:Receptors, Immunologic / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
D018949:Antigens, CD1; D011971:Receptors, Immunologic