CCDC134 (coiled-coil domain containing 134) was firstly identified to be a novel classical secretory protein by our lab. Although we previously identified CCDC134 as a novel MAPK-regulator which down-regulated the Raf-1/MEK/ERK and JNK/ SAPK pathways in some cancer cell lines. However, the critical function of CCDC134 still remains unclear. In view of CCDC134 characteristic, which was widely expressed in lymphocytes, especially up-regulated expression in activated CD4+, CD8+ T lymphocytes and maturated DC, we proposed the hypothesis if CCDC134 was involved in immune response as a potential cytokine. Here, we first found that CCDC134 greatly promoted activation, proliferation and cytotoxicity of CD8+ T cells via augmenting the expression of activation molecules (CD25, CD69) and effector molecules, such as IFN-γ, TNF-α, granzyme B and perforin in vitro. Moreover, by a series of experimental evidences, we have found that CCDC134 displayed strong anti-tumor activity in a CD8+ T cells, but not CD4+ T cells, and IFN-γ-dependent manner in vivo. In addition, CCDC134 markedly promoted phosphorylation of STAT5, but not STAT1, STAT3 in CD8+ T cells and CD8+ T cells proliferation augmented by CCDC134 was dependent on STAT5. Our data collectively suggested that CCDC134, perhaps was served as a so far unidentified cytokine-like protein, which showed strong anti-tumor effects via augmenting CD8+ T cells-mediated tumor immunity.
- Copyright © 2013 by The American Association of Immunologists, Inc.