Changes and significance of IL-25 in chicken collagen II-induced experimental arthritis (CIA).

Rheumatoid arthritis (RA) is an autoimmune inflammatory disease. It is a systemic inflammatory disease, characterized by chronic, symmetrical, multi-articular synovial arthritis. IL-25 (IL-17E) is a member of the recently emerged cytokine family (IL-17s), which is expressed in Th2 cells and bone marrow-derived mast cells. Unlike the other members of this family, IL-25 is capable of inducing Th2-associated cytokines (IL-4, IL-5, and IL-13) and also promotes the release of some pro-immune factors (IL-6 and IL-8). IL-25 is also a pleiotropic factor, which constitutes a tissue-specific pathological injury and chronic inflammation. In this study, we used chicken collagen II-induced experimental arthritis (CIA) model in DBA/1 mice to investigate the relationship between IL-25 and other inflammatory factors, revealing the possible mechanism in CIA. Our results showed that the expression level of IL-25 was enhanced in the late stage of CIA, and IL-17 was increased in the early stage of the disease. It is well known that IL-17 has a crucial role in the development of RA pathogenesis, and IL-25 plays a significant role in humoral immune. For reasons given above, we suggested that the IL-25 inhibited IL-17 expression to some extent, while enhancing the production of IL-4. It was confirmed that IL-25 not only regulated the cellular immune, but also involved the humoral immune in rheumatoid arthritis.

Corynebacterium pyruviciproducens promotes the production of ovalbumin specific antibody via stimulating dendritic cell differentiation and up-regulating Th2 biased immune response.

Corynebacterium pyruviciproducens (C. pyruviciproducens), a newly discovered Corynebacterium, is gram-positive, non-flagellate, non-spore-forming lipophilic rod. No known pathogenic components of Corynebacteria have been found in this new bacterium, such as diphtheria toxin and tuberculostearic acid. In the present study, referring to Propionibacterium acnes (P. acnes), a well-known bacterial adjuvant, the stimulation of dendritic cells by C. pyruviciproducens was analyzed through detecting the levels of cytokine-secretion, ability of cell-proliferation and expression of membrane molecules. In addition, the effect of C. pyruviciproducens in promoting antibody production in vivo was detected. Compared with P. acnes, C. pyruviciproducens more strongly enhanced cytokine secretion including inflammatory factor IL-6 and Th1-associated molecule IL-12, and more effectively induced proliferation, activation or maturation of D2SC/1 (a murine dendritic cell line) and bone marrow-derived dendritic cells (BMDC). Vaccination studies in mice using ovalbumin (OVA) as a model antigen showed that C. pyruviciproducens effectively promoted antigen-specific humoral immune response by increasing OVA-specific antibody, Th2-biased response in spleen and high IL-4/IFN-γ ratio in serum.