Bifidobacteria and S. thermophilus stimulated significant concentrations of transforming growth factor (TGF)-β, an interleukin necessary Compound Library mw for the differentiation of regulatory T cells (Treg)/T helper type 17 (Th17) cells and, as such, the study further examined the induction of
Th17 and Treg cells after PBMC exposure to selected bacteria for 96 h. Data show a significant increase in the numbers of both cell types in the exposed populations, measured by cell surface marker expression and by cytokine production. Probiotics have been shown to induce cytokines from a range of immune cells following ingestion of these organisms. These studies suggest that probiotics’ interaction with immune-competent cells produces a cytokine milieu, exerting immunomodulatory effects on local effector cells, as well as potently inducing differentiation of Th17 and Treg cells. Commensal bacteria in the intestinal lumen play an important role aiding digestion and synthesis of vitamins and nutrients. The composition of the gut bacterial population is relatively stable over time, but this profile can vary considerably between individuals . This balance can be disturbed by dietary changes, stress and antibiotic treatment. However, a healthy balance can be re-established with probiotic supplementation, consisting mainly of Bifidobacterium species and selected lactic acid bacteria (LAB), which protect
the host by excluding pathogenic bacteria and promoting immune Roxadustat manufacturer Methisazone modulatory responses from the gut epithelia . T helper cell (Th) subsets are regulators of the adaptive immune response against infection. Th1-type cells produce cytokines which include interleukin (IL)-2, tumour necrosis factor (TNF)-α and interferon (IFN)-γ, activate macrophages and promote cell-mediated immunity, protective against intracellular infections. Th2-type cells produce a variety of anti-inflammatory cytokines including IL-1 receptor antagonist (IL-1ra), IL-4, IL-5, IL-6, IL-10 and IL-13 and promote humoral immune responses against extracellular pathogens . Th17 cells are a subset of CD4+ T cells that produce a proinflammatory cytokine IL-17. Th17 cells have been shown recently
to play a critical role in clearing pathogens during host defence reactions and in inducing tissue inflammation in autoimmune disease . Regulatory T cells (Treg) are thought to be the master regulators of the immune response in both humans and rodents. Defects in the transcription factor forkhead box protein 3 (FoxP3), which defines the Treg lineage, results in multiple autoimmune diseases and atopy [5,6], demonstrating the central role of FoxP3+ CD4 cells in immune homeostasis. The probiotic, Lactobacillus (Lb) rhamnosus GG, has been shown to influence Th2-, Th1- and Th17-mediated disorders [7,8]. In addition, increases in FoxP3 mRNA expression in peri-bronchial lymph nodes have been noted upon administration of Bifidobacterium lactis Bb12 and Lb.