Relationship between regulatory and type 1 T cells in dogs with oral malignant melanoma.
Recent data suggest a decreased prevalence of IFN-gamma-producing T lymphocytes (Type 1 T cells) in tumor-bearing hosts. Moreover, it has been reported that Treg have a strong impact on the activation and proliferation of CD4 (+) and CD8 (+) lymphocytes; however, no previous reports have described the relationship between Treg and the progression of tumor, or Type 1 T cell populations in dogs with malignant tumor. In this study, the percentage of Treg, Th1, and Tc1 in the peripheral blood of dogs with oral malignant melanoma and healthy dogs was measured and compared. Although the percentages of Th1 and Tc1 in dogs with oral malignant melanoma were less than those in healthy dogs (Th1: P < 0.01, Tc1: P < 0.05), the percentage of Treg was increased (P < 0.01). A significant inverse correlation between the percentage of Tc1 and the clinical tumor stage (P < 0.01), and a significant correlation between that of Treg and the clinical tumor stage (P < 0.001) was found. Moreover, there was a significant inverse correlation between the percentages of Treg and Th1 (P < 0.05) or Tc1 (P < 0.001). In conclusion, the percentage of Treg increases with the tumor stage in the peripheral blood of dogs with oral malignant melanoma. In dogs, Treg appears to suppress Type 1 immunity, which may be responsible for anti-tumor responses.
Japan Animal Referral Medical Center, 2-5-8 Kuji, Takatu-ku, Kawasaki-shi, Kanagawa, 213-0032, Japan. yutaka.horiuchi@jarmec.jp
Yutaka
Y
Horiuchi
Makiko
M
Tominaga
Mika
M
Ichikawa
Masao
M
Yamashita
Kumiko
K
Okano
Yuri
Y
Jikumaru
Yoko
Y
Nariai
Yuko
Y
Nakajima
Masato
M
Kuwabara
Masayoshi
M
Yukawa
D000818:Animals; D016022:Case-Control Studies; D004283:Dog Diseases / Q000276:immunology* / Q000473:pathology; D004285:Dogs; D008545:Melanoma / Q000276:immunology / Q000473:pathology / Q000662:veterinary*; D009062:Mouth Neoplasms / Q000276:immunology / Q000473:pathology / Q000662:veterinary*; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*