Immunomodulatory effects of probiotics in the intestinal tract (original) (raw)
Related papers
Regulation of immune response at intestinal and peripheral sites by probiotics
Biologia, 2006
The gut associated lymphoid tissue (GALT) should protect intestinal mucosa against pathogens, but also avoid hypersensitivity reactions to food proteins, normal bacterial flora and other environmental macromolecules. The interaction between epithelial cells and microflora is fundamental to establish gut mucosal barrier and GALT development. The normal colonization of intestine by commensal bacteria is thus crucial for a correct development of mucosal immune system. Probiotic bacteria are normal inhabitants of microflora and may confer health benefits to the host. The modification of the intestinal microflora towards a healthier probiotics enriched microflora may generate beneficial mucosal immunomodulatory effects and may represent a new strategy to cure intestinal and allergic diseases. The health benefits may be specific for different probiotic strains. Ongoing research is providing new insights into the probiotic beneficial effects and related mechanisms. This review represents an update of immunomodulatory activity of different probiotics and of the more accredited mechanisms underlying such activities.
Immunomodulatory Potentials of Probiotics: A Review
2020
In recent years, research has focused on natural mechanisms for the management, treatment, and curing of human infections and diseases. One of such natural methods is the application of probiotics, which are live microorganisms which when administered in adequate amounts confer a health benefit on the host. The beneficial effects associated with probiotics were originally thought to be a result of improvements in the intestinal microbial balance, however, there are shred evidence that probiotics can also provide benefits by modulating the immune functions. The ability of these probiotics, majorly the Lactobacillus and Bifidobacterium species to boost the immune system is proposed to be a result of their interactions with the cells of the immune system. They have been reported to stimulate various parts of the immune system, through several mechanisms enhancing their functions. It has also been established that the effects of probiotic bacteria may also result from soluble factors fr...
Food & Nutrition Research, 2001
Twenty papers concerning the effects on the immune system of ingestion of probiotic bacteria in humans have been reviewed. Several studies report that intake of probiotics stimulate cellmediated immune effector functions. Thus, enhanced production of interferon-y by blood cells, enhanced phagocytosis by polymorphonuclear leukocytes (PMN) and to a lesser extent monocytes, and enhanced expression of complement receptors on PMNs are effects quite consistently seen in subjects consuming probiotic bacteria. It is likely that this is the result of probiotic bacteria being taken up across the small intestinal mucosa and being ingested by macrophages, leading to the production of cytokines and other mediators stimulating cell-mediated immunity. Probiotics have also been suggested to function as adjuvants, i.e. agents that increase immune responses to other antigens administered concomitantly. However, responses to vaccination are generally only mildly increased during probiotic consumption and most likely depend on the occurrence of cross-reactive antibodies that are induced by the probitic bacteria but also bind to structures on unrelated antigens. A few studies have tested the clinical effect of probiotics on allergy, but to date no effect has been convincingly proven. In conclusion, probiotic treatment could be beneficial in conditions where stimulation of cellmediated effector functions is desired.
Immunomodulatory Effects of Probiotics on Cytokine Profiles
Probiotics confer immunological protection to the host through the regulation, stimulation, and modulation of immune responses. Researchers have shifted their attention to better understand the immunomodulatory effects of probiotics, which have the potential to prevent or alleviate certain pathologies for which proper medical treatment is as yet unavailable. It has been scientifically established that immune cells (T-and B-cells) mediate adaptive immunity and confer immunological protection by developing pathogen-specific memory. However, this review is intended to present the recent studies on immunomodulatory effects of probiotics. In the early section of this review, concepts of probiotics and common probiotic strains are focused on. On a priority basis, the immune system, along with mucosal immunity in the human body, is discussed in this study. It has been summarized that a number of species of Lactobacillus and Bifidobacterium exert vital roles in innate immunity by increasing the cytotoxicity of natural killer cells and phagocytosis of macrophages and mediate adaptive immunity by interacting with enterocytes and dendritic, Th1, Th2, and Treg cells. Finally, immunomodulatory effects of probiotics on proinflammatory and anti-inflammatory cytokine production in different animal models have been extensively reviewed in this paper. Therefore, isolating new probiotic strains and investigating their immunomodulatory effects on cytokine profiles in humans remain a topical issue.
Beneficial Effects of Probiotic Consumption on the Immune System
Annals of Nutrition and Metabolism
Background: The gastrointestinal tract is one of the most microbiologically active ecosystems that plays a crucial role in the working of the mucosal immune system (MIS). In this ecosystem, the consumed probiotics stimulate the immune system and induce a network of signals mediated by the whole bacteria or their cell wall structure. This review is aimed at describing the immunological mechanisms of probiotics and their beneficial effects on the host. Summary: Once administered, oral probiotic bacteria interact with the intestinal epithelial cells (IECs) or immune cells associated with the lamina propria, through Toll-like receptors, and induce the production of different cytokines or chemokines. Macrophage chemoattractant protein 1, produced by the IECs, sends signals to other immune cells leading to the activation of the MIS, characterized by an increase in immunoglobulin A+ cells of the intestine, bronchus and mammary glands, and the activation of T cells. Specifically, probiotics...
BMC Gastroenterology, 2022
Background: Oral administration of health-promoting bacteria is increasingly used in clinical practise. These bacteria have anti-inflammatory characteristics and modulate the immune system without major reported side effects. The mechanisms of action are not yet fully defined. Our aim was to study systemic effects of probiotics by measurements of leukocytes as well as local effects on rectal mucosal biopsies after adding a standardized inflammatory stimulus in vitro. Methods: Fourteen healthy subjects were randomized to receive 10 10 colony forming units/day orally of the probiotic strain Lactiplantibacillus plantarum 299 (Lp299), n = 7, or Bifidobacterium infantis CURE21 (CURE21), n = 7, for six weeks. Rectal biopsies were taken before and after ingestion of either probiotic strain product, for stimulation in vitro with tumour necrosis factor alpha (TNF-α) at 10 and 100 ng/ml respectively up to 8 h. Blood tests were sampled before and after treatment. Lactate dehydrogenase (LDH) confirmed viable tissue. Results: Composition of the intestinal microbiota was not changed. Systemic leukocytes decreased after administration of CURE21 (P<0.05) and Lp299 (P<0.01). Levels of the pro-inflammatory cytokine IL-6 in rectal mucosa after stimulation with TNF-α were attenuated after ingestion of Lp299. No effect was seen with CURE21. Conclusions: Administration of these probiotic strains to healthy humans show both a systemic and local reduction of inflammatory response by lowering leukocyte counts, and for Lp299 IL-6 levels in rectal mucosa. Probiotics may play an important role in the reduction of inflammatory responses expected after trauma during surgery or after pelvic irradiation.
Immunologic effects of probiotics and human health
Microbiology Australia
The human gastrointestinal tract (GIT) harbours an extremely complex and diverse microbial ecosystem representing over 500 different species. While a majority of indigenous bacteria are benign or beneficial, some possess the potential to cause disease; in healthy individuals, a balance exists between these populations. In addition to nutritional and barrier functions, the intestinal microflora plays an important role in guiding the development of a balanced immune system and maintaining gut homeostasis. Perturbations in the microbial homeostasis due to factors such as antibiotic therapy, stress and infection enhances predisposition to increased risk of infectious diseases, cancers and immunoinflammatory disorders.
Immunomodulatory Properties of Probiotics and Their Derived Bioactive Compounds
Applied sciences, 2023
Immune system modulation is an intriguing part of scientific research. It is well established that the immune system plays a crucial role in orchestrating cellular and molecular key mediators, thus establishing a powerful defense barrier against infectious pathogens. Gut microbiota represent a complex community of approximately a hundred trillion microorganisms that live in the mammalian gastrointestinal (GI) tract, contributing to the maintenance of gut homeostasis via regulation of the innate and adaptive immune responses. However, impairment in the crosstalk between intestinal immunity and gut microbiota may reflect on detrimental health issues. In this context, many studies have indicated that probiotics and their bioactive compounds, such as bacteriocins and short chain fatty acids (SCFAs), display distinct immunomodulatory properties through which they suppress inflammation and enhance the restoration of microbial diversity in pathological states. This review highlights the fundamental features of probiotics, bacteriocins, and SCFAs, which make them ideal therapeutic agents for the amelioration of inflammatory and autoimmune diseases. It also describes their underlying mechanisms on gut microbiota modulation and emphasizes how they influence the function of immune cells involved in regulating gut homeostasis. Finally, it discusses the future perspectives and challenges of their administration to individuals.
Probiotics importance and their immunomodulatory properties
Journal of Cellular Physiology, 2018
Mammalian intestine contains a large diversity of commensal microbiota, which is far more than the number of host cells. Probiotics play an insecure and protective role against the colonization of intestinal pathogenic microbes and increase mucosal integrity by stimulating epithelial cells. Probiotics have innate capabilities in many ways, including receptor antagonism, receptor expression, binding and expression of adapter proteins, expression of negative regulatory signal molecules, induction of microRNAs, endotoxin tolerance, and ultimately secretion of immunomodulatory proteins, lipids, and metabolites to modulate the immune system. Probiotic bacteria