title: Differential IL-12 responsiveness of T cells but not of NK cells from tumor-bearing mice in IL-12-responsive versus -unresponsive tumor models.
abstract: While IL-12 administration induces tumor regression through stimulating T cells in tumor-bearing mice, this IL-12 effect is observed in some but not all tumor models. The present study aimed to compare IL-12 responsiveness of T cells from tumor-bearing mice in IL-12-responsive (CSA1M and OV-HM) and -unresponsive (Meth A) tumor models. Tumor regression in IL-12-responsive tumor models required the participation of T cells, but not of NK1.1(+) cells. Because a NK1.1(+) cell population was the major producer of IFN-gamma, comparable levels of IFN-gamma production were induced in IL-12-responsive and -unresponsive tumor-bearing mice. This indicates that the amount of IFN-gamma produced in tumor-bearing individuals does not correlate with the anti-tumor efficacy of IL-12. In contrast, IL-12 responsiveness of T cells differed between the responsive and unresponsive models: purified T cells from CSA1M/OV-HM-bearing or Meth A-bearing mice exhibited high or low IL-12 responsiveness respectively, when evaluated by the amounts of IFN-gamma produced in response to IL-12. T cells from CSA1M- or OV-HM-bearing but not from Meth A-bearing mice exhibited enhanced levels of mRNA for the IL-12 receptor (IL-12R). These results indicate that a fundamental difference exists in IL-12 responsiveness of T cells between IL-12-responsive and -unresponsive tumor models, and that such a difference is associated with the expression of IL-12R on T cells.
authors.affiliation: Department of Oncology, Biomedical Research Center, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Suita, Osaka 565-0871, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Iwasaki
authors.forename: W G
authors.initials: WG
authors.lastname: Yu
authors.forename: Y
authors.initials: Y
authors.lastname: Uekusa
authors.forename: C
authors.initials: C
authors.lastname: Nakajima
authors.forename: Y F
authors.initials: YF
authors.lastname: Yang
authors.forename: P
authors.initials: P
authors.lastname: Gao
authors.forename: R
authors.initials: R
authors.lastname: Wijesuriya
authors.forename: H
authors.initials: H
authors.lastname: Fujiwara
authors.forename: T
authors.initials: T
authors.lastname: Hamaoka
mesh_terms: D000818:Animals; D000941:Antigens / Q000276:immunology; D000950:Antigens, Ly; D000954:Antigens, Surface; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000187:drug effects / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D007371:Interferon-gamma / Q000032:analysis / Q000097:blood; D018664:Interleukin-12 / Q000276:immunology / Q000627:therapeutic use*; D007694:Killer Cells, Natural / Q000187:drug effects / Q000276:immunology*; D037181:Lectins, C-Type; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D055651:NK Cell Lectin-Like Receptor Subfamily B; D009374:Neoplasms, Experimental / Q000188:drug therapy* / Q000276:immunology; D011506:Proteins / Q000276:immunology; D012333:RNA, Messenger / Q000032:analysis; D018123:Receptors, Interleukin / Q000032:analysis / Q000235:genetics; D053707:Receptors, Interleukin-12; D013154:Spleen / Q000276:immunology; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D013997:Time Factors; D014407:Tumor Cells, Cultured; D019139:Tumor Escape
chemical_list: D000941:Antigens; D000950:Antigens, Ly; D000954:Antigens, Surface; C527211:Klrb1c protein, mouse; D037181:Lectins, C-Type; D055651:NK Cell Lectin-Like Receptor Subfamily B; D011506:Proteins; D012333:RNA, Messenger; D018123:Receptors, Interleukin; D053707:Receptors, Interleukin-12; D018664:Interleukin-12; D007371:Interferon-gamma