Immunosuppressive Effects of Two Probiotics, Lactobacillus paracasei DSM 13434 and Lactobacillus plantarum DSM 15312, on CD4+ T Cells of Multiple Sclerosis Patients

T cells play an important role in the development and progression of multiple sclerosis (MS), an autoimmune disease of the central nervous system. In the present study, the immunomodulatory impacts of two Lactobacillus strains, L paracasei DSM 13434 and L plantarum DSM 15312, on the frequency and cytokine production of CD4+ T cells in MS patients were explored. Thirty MS patients were enrolled in this study. The CD4+ T cells were isolated, cultured, and exposed to the media containing cell-free supernatants of L plantarum (group1), L paracasei (group 2), the mixture group of cell-free supernatants of both probiotics (group 3), and vehicle (control) group (group 4). The frequencies of T helper (Th) 1, Th17, Th2, and T regulatory type 1 (Tr1) cells and mean fluorescent intensity (MFI) of the associated cytokines were assessed using flow cytometry. The levels of interleukin 17 (IL-17), transforming growth factor β (TGF-β), and interferon-gamma (IFN-γ) cytokines in supernatants of all groups were measured by enzyme-linked immunosorbent assay. The percentage of Th1 cells and the MFI of IFN-γ in Th1 cells (CD4+ IFN-γ+) in all three probiotic treatment groups were significantly decreased compared to the control group. However, no significant changes were observed in the proportion and MFI of Th2, Th17, and Tr1 cells. A significant decrease was observed in IL-17 secretion in the supernatant of cultured CD4+ T cells in all three treatment groups in comparison with control. The levels of TGF-β and IFN-γ were not significantly different among any of the study groups.  Collectively, cell-free supernatants of the lactobacilli showed an in vitro anti-inflammatory effect. However, further studies are needed to prove the real effects of probiotics on MS.