Molecular characterization of immunoinhibitory factors PD-1/PD-L1 in chickens infected with Marek’s disease virus

作者：Ayumi Matsuyama-Kato, Shiro Murata, Masayoshi Isezaki, Rika Kano, Sara Takasaki, Osamu Ichii, Satoru Konnai, Kazuhiko Ohashi · 发表于：Virology Journal · 年份：2012 · DOI：10.1186/1743-422x-9-94 · 被引用次数：26 · 研究领域：Cancer Immunotherapy and Biomarkers、Animal Virus Infections Studies、Herpesvirus Infections and Treatments

BACKGROUND: An immunoinhibitory receptor, programmed death-1 (PD-1), and its ligand, programmed death-ligand 1 (PD-L1), are involved in immune evasion mechanisms for several pathogens causing chronic infections and for neoplastic diseases. However, little has been reported for the functions of these molecules in chickens. Thus, in this study, their expressions and roles were analyzed in chickens infected with Marek's disease virus (MDV), which induces immunosuppression in infected chickens. RESULTS: A chicken T cell line, Lee1, which constitutively produces IFN-γ was co-cultured with DF-1 cells, which is a spontaneously immortalized chicken fibroblast cell line, transiently expressing PD-L1, and the IFN-γ expression level was analyzed in the cell line by real-time RT-PCR. The IFN-γ expression was significantly decreased in Lee1 cells co-cultured with DF-1 cells expressing PD-L1. The expression level of PD-1 was increased in chickens at the early cytolytic phase of the MDV infection, while the PD-L1 expression level was increased at the latent phase. In addition, the expression levels of PD-1 and PD-L1 were increased at tumor lesions found in MDV-challenged chickens. The expressions levels of PD-1 and PD-L1 were also increased in the spleens and tumors derived from MDV-infected chickens in the field. CONCLUSIONS: We demonstrated that the chicken PD-1/PD-L1 pathway has immunoinhibitory functions, and PD-1 may be involved in MD pathogenesis at the early cytolytic phase of the MD...