title: Decreased number and reduced NKG2D expression of Vδ1 γδ T cells are involved in the impaired function of Vδ1 γδ T cells in the tissue of gastric cancer.
abstract: BACKGROUND
  In cancer patients, impaired function of immune cells--such as CD8(+) T cells, NK cells, and dendritic cells--reportedly results in tumor progression. Although γδ T cells also play a critical role in tumor defense, their function remains unclear in cancer patients.
  
  
  METHODS
  The frequency and function of γδ T cells in peripheral blood, normal gastric mucosa, and cancer tissue were evaluated by multicolor flow cytometry. We also determined NKG2D expression on γδ T cells in gastric cancer patients.
  
  
  RESULTS
  The frequency of Vδ1 γδ T cells in gastric cancer tissue is significantly lower than in normal gastric mucosa; however, differences in the frequencies of Vδ2 and Vγ9 γδ T cells between normal gastric mucosa and gastric cancer tissue were not statistically significant. The Vδ1 γδ T cells from gastric cancer tissue produce significantly less IFN-γ than those from normal gastric mucosa do. Expression of NKG2D on Vδ1 γδ T cells from gastric cancer tissue was significantly lower than in normal gastric mucosa. We also found a significant correlation between NKG2D expression and IFN-γ production of Vδ1 γδ T cells in gastric cancer tissue.
  
  
  CONCLUSIONS
  Vδ1 γδ T cells show decreased frequency and impaired function in gastric cancer tissue, for which decreased NKG2D expression might be one of the mechanisms. Modalities specifically targeting NKG2D in Vδ1 γδ T cells may provide a breakthrough treatment for gastric cancer patients.
authors.affiliation: Division of Surgical Oncology, Department of Surgery, Tottori University School of Medicine, 36-1 Nishi-cho, Yonago 683-8504, Japan.
authors.forename: Hirohiko
authors.initials: H
authors.lastname: Kuroda
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Saito
authors.forename: Masahide
authors.initials: M
authors.lastname: Ikeguchi
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D005260:Female; D005753:Gastric Mucosa / Q000166:cytology / Q000378:metabolism; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D055655:NK Cell Lectin-Like Receptor Subfamily K / Q000378:metabolism*; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000378:metabolism*; D012016:Reference Values; D013274:Stomach Neoplasms / Q000378:metabolism* / Q000473:pathology*; D016176:T-Lymphocyte Subsets / Q000378:metabolism* / Q000473:pathology
chemical_list: C527085:KLRK1 protein, human; D055655:NK Cell Lectin-Like Receptor Subfamily K; D016692:Receptors, Antigen, T-Cell, gamma-delta; D007371:Interferon-gamma