Probiotics importance and their immunomodulatory properties

Area of Science:

• Microbiology
• Immunology
• Gastroenterology

Background:

• Mammalian intestines host a vast diversity of commensal microbiota, outnumbering host cells.
• Probiotics offer protection against pathogenic microbes and enhance mucosal integrity by stimulating epithelial cells.

Purpose of the Study:

• To elucidate the multifaceted mechanisms by which probiotics modulate the host immune system.
• To explore the impact of probiotics on intestinal homeostasis, inflammation, and immune cell differentiation.

Main Methods:

• Analysis of probiotic mechanisms including receptor interactions, signaling molecule modulation, and metabolite secretion.
• Investigation of probiotic effects on key inflammatory pathways like nuclear factor-kappa B (NF-κβ) and mitogen-activated protein kinases (MAPKs).
• Examination of probiotic influence on immune cell populations such as T helper 17 (Th17) and regulatory T (Treg) cells in the gut lamina propria.

Main Results:

• Probiotics suppress inflammation by inhibiting pathways such as NF-κβ and potentially MAPKs, and by reducing lipopolysaccharide (LPS) binding to CD14.
• Probiotic modulation results in increased cytokine production, mucin secretion, phagocytic activity, and activation of T and natural killer T cells.
• Intestinal microbiota composition influences the differentiation of lamina propria cells, impacting Th17 and Treg cell balance.

Conclusions:

• Probiotics exert significant immunomodulatory effects through diverse direct and indirect mechanisms.
• Probiotics play a crucial role in maintaining intestinal immune homeostasis and can suppress inflammatory responses.
• The gut microbiota composition is intrinsically linked to the balance of immune cells in the intestinal lamina propria, affecting systemic immunity.