activation-induced cytidine deaminase expression in cd4+ t cells is associated with a unique il-10-producing subset that increases with ageactivation-induced胞嘧啶核苷脱氨酶表达cd4 + t细胞与一个独特的il-10-producing子集,随着年龄的增加.pdfVIP

Activation-Induced Cytidine Deaminase Expression in CD4+ T Cells is Associated with a Unique IL-10-Producing Subset that Increases with Age 1¤a 2 1 1 1¤b Hongyan Qin , Keiichiro Suzuki , Mikiyo Nakata , Shunsuke Chikuma , Nakako Izumi , Le Thi 1 2 2 3 1 Huong , Mikako Maruya , Sidonia Fagarasan , Meinrad Busslinger , Tasuku Honjo *, Hitoshi 1 ¤c Nagaoka * 1 Department of Immunology and Genomic Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan, 2 Laboratory for Mucosal Immunity, RIKEN, Yokohama, Japan, 3 Research Institute of Molecular Pathology, Vienna Biocenter, Vienna, Austria Abstract Activation-induced cytidine deaminase (AID), produced by the Aicda gene, is essential for the immunoglobulin gene (Ig) alterations that form immune memory. Using a Cre-mediated genetic system, we unexpectedly found CD4+ T cells that had expressed Aicda (exAID cells) as well as B cells. ExAID cells increased with age, reaching up to 25% of the CD4+ and B220+ + cell populations. ExAID B cells remained IgM , suggesting that class-switched memory B cells do not accumulate in the spleen. In T cells, AID was expressed in a subset that produced IFN-c and IL-10 but little IL-4 or IL-17, and showed no evidence of genetic mutation. Interestingly, the endogenous Aicda expression in T cells was enhanced in the absence of B cells, indicating that the process is independent from the germinal center reaction. These results suggest that in addi