Mechanism of Action of Probiotic Bacteria on Intestinal and Systemic Immunities and Antigen-Presenting Cells

Abstract

Immunomodulation has been shown to be one of the major functions of probiotic bacteria. This review is presented to provide detailed information on the immunomodulatory properties of probiotics in various animal models and clinical practices. Probiotics can regulate helper T (Th) responses and release of cytokines in a strain-specific manner. For example, Lactobacillus rhamnosus GG can induce beneficial Th1 immunomodulatory effect in infants with cow's milk allergy and relieve intestinal inflammation in atopic children by promoting IL-10 generation. Mechanism of action of probiotics on antigen-presenting cells at gastrointestinal tract is also postulated in this review. Probiotic bacterial cells and their soluble factors may activate dendritic cells, macrophages, and to certain extent monocytes via toll-like-receptor recognition and may further provoke specific Th responses. They are speculated to elicit immunomodulatory effects on intestinal and systemic immunities.

Reduced Th22 cell proportion and prevention of atopic dermatitis in infants following maternal probiotic supplementation

“…Previous animal and in vitro studies suggest that immunomodulatory effects of probiotics are related to an increase of Tregs . However, similar to previous clinical studies on the effects of probiotics in children, we did not find that maternal probiotics affected the Tregs .…”

“…Early intestinal microbiota is essential for normal maturation of the immune system and T cell balance, and unfavourable composition of the microbiota is associated with T cell inflammation in AD . Probiotic bacteria have the ability to modify the Th balance through their effects on dendritic cells, but there are conflicting results on the distinct effects of probiotics on T cell subsets in children. Some studies have reported a skewing towards a Th1 profile with increase in interferon gamma (IFNγ), while others have reported no effect on either the Th1/Th2 balance or Tregs .…”

Lactobacillus casei DG and its postbiotic reduce the inflammatory mucosal response: an ex-vivo organ culture model of post-infectious irritable bowel syndrome

“…Randomised controlled trials demonstrated that probiotics were effective in the modulation of symptom’s pattern of IBS patients [19–24]. However, the majority of the studies have been performed in non-specific IBS rather than in PI-IBS D, so that the exact role of probiotics in the management of these patients remains to be elucidated.…”

The probiotic activity of Lactobacillus murinus against food allergy

“…Modulatory effects on DC have been postulated as a critical mechanism for probiotic-mediated immune modulation (Amar et al, 2015;Dongarrà et al, 2013;Fong, Kirjavainen, Wong, & El-Nezami, 2015;Fong, Shah, Kirjavainen, & El-Nezami, 2015;Martínez-Abad et al, 2016;Yang et al, 2015). However, direct evidence linking the effects of LAB on DC functionality and food allergy is scarce.…”