New approach to the immunomodulatory effects of calcitriol in NMRI-mouse

Recent evidence demonstrated an important role for Th-17 and FoxP3亷 lymphocytes in immunity system .Although, previous reports have determined the immunomodulatory potential of calcitriol, but this study was mostly done before the discovery of recent lymphocytes. The present study was set out to investigate the effects of calcitriol on immunity system in NRMI-mice after challenge with sheep red blood cells (SRBC). The study population was consist of 14 male mice that randomly allocated in two equal groups and immunized with SRBC. Mice in the treatment group were intraperitoneally received 5 μg/Kg calcitriol every other day from the beginning of the study and continued for 2 weeks. The results of the present study indicated a significant increase in the level of anti-SRBC antibody and simultaneously a significant decrease in the level of DTH in the treatment group compared to control group. The level of respiratory burst in phagocytic cells of splenocytes and the level of lymphocyte proliferation were significantly decreased in treatment group compared to control group. Moreover, calcitriol caused a significant reduction in the production of pro-inflammatory IL-17 as well as IFN-γ, parallel to increasing FoxP3亷 cells. Also the level of anti-inflammatory IL-10 was significantly increased. Therefore, the major immunomudlatoty effects of calciteriol may be due to a significant decrease in Th17 cells activity and concurrently a significant decrease in the expansion of FoxP3亷 lymphocytes.