title: Flow cytometric analysis of peripheral blood and tumor-infiltrating regulatory T cells in dogs with oral malignant melanoma.
abstract: It is well known that tumor-infiltrating lymphocytes (TILs) and peripheral blood lymphocytes (PBLs) from patients with advanced-stage cancer have a poor immune response. Regulatory T cells (Tregs), characterized by the expression of a cluster of differentiation 4 and intracellular FoxP3 markers, can inhibit antitumor immunoresponse. In the present study, the prevalence of Tregs in peripheral blood and tumor tissue from dogs with oral malignant melanoma was evaluated by triple-color flow cytometry. The percentage of Tregs in the peripheral blood of the dogs with malignancy was significantly increased compared with healthy control dogs, and the percentage of Tregs within tumors was significantly increased compared with Tregs in peripheral blood of dogs with oral malignant melanoma. This finding suggests that the presence of tumor cells induced either local proliferation or selective migration of Tregs to tumor-infiltrated sites. A better understanding of the underlying mechanisms of Treg regulation in patients with cancer may lead to an effective anticancer immunotherapy against canine malignant melanoma and possibly other tumors.
authors.affiliation: Japan Animal Referral Medical Center, 2-5-8 Kuji, Takatu-ku, Kawasaki-shi, Kanagawa 213-0032, Japan.
authors.forename: Makiko
authors.initials: M
authors.lastname: Tominaga
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Horiuchi
authors.forename: Mika
authors.initials: M
authors.lastname: Ichikawa
authors.forename: Masao
authors.initials: M
authors.lastname: Yamashita
authors.forename: Kumiko
authors.initials: K
authors.lastname: Okano
authors.forename: Yuri
authors.initials: Y
authors.lastname: Jikumaru
authors.forename: Yoko
authors.initials: Y
authors.lastname: Nariai
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Kadosawa
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D004283:Dog Diseases / Q000276:immunology*; D004285:Dogs; D005434:Flow Cytometry; D006801:Humans; D008545:Melanoma / Q000097:blood / Q000276:immunology / Q000662:veterinary*; D009062:Mouth Neoplasms / Q000097:blood / Q000276:immunology / Q000662:veterinary*; D012016:Reference Values; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*