In vitro differential modulation of immune response by probiotics in porcine peripheral blood mononuclear cells

The purpose of this study was to evaluate the extent of cytokine induction and T cell proliferation in lactic acid bacteria (LAB)-stimulated porcine peripheral blood mononuclear cells (PBMCs). Porcine PBMCs were stimulated with phytohaemagglutinin (PHA) and then incubated with Bifidobacterium angulatum, Enterococcus faecalis and Lactobacillus reuteri. A decrease in the mRNA expression of interferon-gamma (IFN-γ) was detected; however, only a significant increase (P<0.05) in interleukin (IL)-10 expression was found in cells stimulated with E. faecalis. No changes in transforming growth factor-beta (TGF-β) were observed with neither of the probiotics tested nor in T cell proliferation between LAB-stimulated and control groups. These results suggest a possible immunomodulatory probiotic effect and this effect could be due to a decrease in the inflammatory T helper 1 (Th1) immune response, and an increase of T regulatory function, as suggested by the augmented expression of IL-10.