Lactobacillus sakeisuppresses collagen-induced arthritis and modulates the differentiation of T helper 17 cells and regulatory B cells

Background To evaluate the immunomodulatory effect ofLactobacillus sakeiin a mouse model of rheumatoid arthritis (RA) and in human immune cells. Methods We evaluated whetherL. sakeireduced the severity of collagen-induced arthritis (CIA) and modulated interleukin (IL)-17 and IL-10 levels, as well as whether it affected the differentiation of CD4(+)T cells and regulatory B cells. We evaluated osteoclastogenesis after culturing bone marrow-derived mononuclear cells withL. sakei. Results The differentiation of T helper 17 cells and the serum level of IL-17 were suppressed byL. sakeiin both human peripheral blood mononuclear cells and mouse splenocytes. The serum level of IL-10 was significantly increased in theL. sakei-treated group, whereas the regulatory T cell population was unchanged. The population of regulatory B cells significantly increased the inL. sakei-treated group. Oral administration ofL. sakeireduced the arthritis incidence and score in mice with CIA. Finally, osteoclastogenesis and the mRNA levels of osteoclast-related genes were suppressed in theL. sakei-treated group. Conclusion L. sakeiexerted an anti-inflammatory effect in an animal model of RA, regulated Th17 and regulatory B cell differentiation, and suppressed osteoclastogenesis. Our findings suggest thatL. sakeihas therapeutic potential for RA.