Lactic acid bacteria and probiotic organisms induce different cytokine profile and regulatory T cells mechanisms

Immuno-modulatory effects of seventeen lactic acid bacteria (LAB) and probiotic strains were assessed following stimulation with peripheral blood mononuclear cells. Pro- and anti-inflammatory cytokines including interleukin (IL)-2, IL-4, IL-10, IL-12 p70, interferon (IFN)-γ, tumor necrosis factor (TNF)-α and transforming growth factor (TGF)-β measured at different time points shows that all strains stimulated significant cytokines in varying concentrations and strain specific manner. Overall, TNF-α, IFN-γ, IL-10 and TGF-β were stimulated at high concentrations where Lactobacillus casei 290 and Streptococcus thermophilus M5 stimulated TNF-α and IFN-γ and Bifidobacterium strains stimulated maximum levels of IL-10 and TGF-β respectively. A significant increase in CD3+CD4+CD25+ and Treg population was observed where S. thermophilus M5 and 1342, B. animalis subsp. lactis BB12 and L. casei 290 showed seven-fold increase in FoxP3 expression. The study suggests that LAB and probiotics strains differ in their immuno-modulatory responses and functions, which necessitates their careful selection and characterization before applications.