Mechanisms and immunomodulatory properties of pre- and probiotics

2019 ◽  
Vol 10 (3) ◽  
pp. 225-236 ◽  
Author(s):  
V.B.M. Peters ◽  
E. van de Steeg ◽  
J. van Bilsen ◽  
M. Meijerink

The human body is exposed to many xenobiotic, potentially harmful compounds. The intestinal immune system is crucial in protecting the human body from these substances. Moreover, many microorganisms, residing in the gastrointestinal tract, play an important role in modulating immune responses. Pre- and probiotics may have beneficial effects on the microbial composition and activity within the human gut, subsequently affecting the immune system. Prebiotics can exert their effects via different mechanisms, like selectively stimulating the growth of bacteria by providing substrates or via direct immune stimulation. Probiotics may have beneficial health effects via competition with pathogens for substrates and binding intestinal sites, bioconversions of for example sugars into fermentation products with inhibitory properties, production of growth substrates like vitamins for the host, direct antagonism of pathogens via antimicrobial peptide production, reduction of inflammation and stimulation of immune cells. This review focuses on the different mechanisms via which the pre- and probiotics exert their beneficial effects on the host, addressing their immunomodulatory properties in particular.

mSphere ◽  
2019 ◽  
Vol 4 (6) ◽  
Author(s):  
Mateus Silveira Freitas ◽  
Vânia Luiza Deperon Bonato ◽  
Andre Moreira Pessoni ◽  
Marcio L. Rodrigues ◽  
Arturo Casadevall ◽  
...  

ABSTRACT The release of extracellular vesicles (EVs) by fungi is a fundamental cellular process. EVs carry several biomolecules, including pigments, proteins, enzymes, lipids, nucleic acids, and carbohydrates, and are involved in physiological and pathological processes. EVs may play a pivotal role in the establishment of fungal infections, as they can interact with the host immune system to elicit multiple outcomes. It has been observed that, depending on the fungal pathogen, EVs can exacerbate or attenuate fungal infections. The study of the interaction between fungal EVs and the host immune system and understanding of the mechanisms that regulate those interactions might be useful for the development of new adjuvants as well as the improvement of protective immune responses against infectious or noninfectious diseases. In this review, we describe the immunomodulatory properties of EVs produced by pathogenic fungi and discuss their potential as adjuvants for prophylactic or therapeutic strategies.


2017 ◽  
Vol 108 (3) ◽  
pp. 351-359 ◽  
Author(s):  
K. Walkowiak-Nowicka ◽  
G. Nowicki ◽  
M. Kuczer ◽  
G. Rosiński

AbstractIn insects, two types of the immune responses, cellular and humoral, constitute a defensive barrier against various parasites and pathogens. In response to pathogens, insects produce a wide range of immune agents that act on pathogens directly, such as cecropins or lysozyme, or indirectly by the stimulation of hemocyte migration or by increasing phenoloxidase (PO) activity. Recently, many new immunologically active substances from insects, such as peptides and polypeptides, have been identified. Nevertheless, in the most cases, their physiological functions are not fully known. One such substance is yamamarin – a pentapeptide isolated from the silk mothAntheraea yamamai. This yamamarin possesses strong antiproliferative properties and is probably involved in diapause regulation. Here, we examined the immunotropic activity of yamamarin by testing its impact on selected functions of the immune system in heterologous bioassays with the beetleTenebrio molitor, commonly known as a stored grains pest. Our results indicate that the pentapeptide affects the activity of immune processes in the beetle. We show that yamamarin induces changes in both humoral and cellular responses. The yamamarin increases the activity of PO, as well as causes changes in the hemocyte cytoskeleton and stimulates phagocytic activity. We detected an increased number of apoptotic hemocytes, however after the yamamarin injection, no significant variations in the antibacterial activity in the hemolymph were observed. The obtained data suggest that yamamarin could be an important controller of the immune system inT. molitor.


2021 ◽  
Vol 9 ◽  
Author(s):  
Patrice Debré ◽  
Marie Neunez ◽  
Michel Goldman

Ebola virus disease is one of the deadliest infections in the world today. The microbe to blame is the Ebola virus. It has already caused numerous outbreaks in Africa, in the regions located south of the Sahara. This article describes the main characteristics of this infectious disease as well as the currently available treatments, namely vaccines and antibodies. Antibodies are produced by the human body when it is infected by a microbe. Antibodies can be collected from the blood of infected humans or animals and purified or manufactured in a laboratory to produce drugs. While vaccines have demonstrated their effectiveness in preventing infectious diseases, antibodies are effective in stopping the progression of several infectious diseases. In this article, you will discover that the stimulation of the immune system, either by the vaccine or by antibodies, is essential to tackle Ebola virus disease.


2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
Rea Bingula ◽  
Marc Filaire ◽  
Nina Radosevic-Robin ◽  
Mathieu Bey ◽  
Jean-Yves Berthon ◽  
...  

The microbiota includes different microorganisms consisting of bacteria, fungi, viruses, and protozoa distributed over many human body surfaces including the skin, vagina, gut, and airways, with the highest density found in the intestine. The gut microbiota strongly influences our metabolic, endocrine, and immune systems, as well as both the peripheral and central nervous systems. Recently, a dialogue between the gut and lung microbiota has been discovered, suggesting that changes in one compartment could impact the other compartment, whether in relation to microbial composition or function. Further, this bidirectional axis is evidenced in an, either beneficial or malignant, altered immune response in one compartment following changes in the other compartment. Stimulation of the immune system arises from the microbial cells themselves, but also from their metabolites. It can be either direct or mediated by stimulated immune cells in one site impacting the other site. Additionally, this interaction may lead to immunological boost, assisting the innate immune system in its antitumour response. Thus, this review offers an insight into the composition of these sites, the gut and the lung, their role in shaping the immune system, and, finally, their role in the response to lung cancer.


1996 ◽  
Vol 9 (3) ◽  
pp. 349-360 ◽  
Author(s):  
H S Lillehoj ◽  
J M Trout

Coccidiosis, an intestinal infection caused by intracellular protozoan parasites belonging to several different species of Eimeria, seriously impairs the growth and feed utilization of livestock and poultry. Host immune responses to coccidial infection are complex. Animals infected with Eimeria spp. produce parasite-specific antibodies in both the circulation and mucosal secretions. However, it appears that antibody-mediated responses play a minor role in protection against coccidiosis. Furthermore, there is increasing evidence that cell-mediated immunity plays a major role in resistance to infection. T lymphocytes appear to respond to coccidial infection through both cytokine production and a direct cytotoxic attack on infected cells. The exact mechanisms by which T cells eliminate the parasites, however, remain unclear. Although limited information is available on the intestinal immune system of chickens, gut lymphoid tissues have evolved specialized features that reflect their role as the first line of defense at mucosal surfaces, including both immunoregulatory cells and effector cells. This review summarizes our current understanding of the avian intestinal immune system and mucosal immune responses to Eimeria spp., providing an overview of the complex cellular and molecular events involved in intestinal immune responses to enteric pathogens.


2021 ◽  
Vol 22 (12) ◽  
pp. 6326
Author(s):  
Jung A. Eom ◽  
Goohyun Kwon ◽  
Nayeon Kim ◽  
Eunju Park ◽  
Sungmin Won ◽  
...  

The gut microbiota has been known to modulate the immune responses in chronic liver diseases. Recent evidence suggests that effects of dietary foods on health care and human diseases are related to both the immune reaction and the microbiome. The gut-microbiome and intestinal immune system play a central role in the control of bacterial translocation-induced liver disease. Dysbiosis, small intestinal bacterial overgrowth, translocation, endotoxemia, and the direct effects of metabolites are the main events in the gut-liver axis, and immune responses act on every pathways of chronic liver disease. Microbiome-derived metabolites or bacteria themselves regulate immune cell functions such as recognition or activation of receptors, the control of gene expression by epigenetic change, activation of immune cells, and the integration of cellular metabolism. Here, we reviewed recent reports about the immunologic role of gut microbiotas in liver disease, highlighting the role of diet in chronic liver disease.


2021 ◽  
Vol 14 ◽  
pp. 175628482110180
Author(s):  
Ruicong Sun ◽  
Chunjin Xu ◽  
Baisui Feng ◽  
Xiang Gao ◽  
Zhanju Liu

Bile acids are a class of cholesterol derivatives that have been known for a long time for their critical roles in facilitating the digestion and absorption of lipid from the daily diet. The transformation of primary bile acids produced by the liver to secondary bile acids appears under the action of microbiota in the intestine, greatly expanding the molecular diversity of the intestinal environment. With the discovery of several new receptors of bile acids and signaling pathways, bile acids are considered as a family of important metabolites that play pleiotropic roles in regulating many aspects of human overall health, especially in the maintenance of the microbiota homeostasis and the balance of the mucosal immune system in the intestine. Accordingly, disruption of the process involved in the metabolism or circulation of bile acids is implicated in many disorders that mainly affect the intestine, such as inflammatory bowel disease and colon cancer. In this review, we discuss the different metabolism profiles in diseases associated with the intestinal mucosa and the diverse roles of bile acids in regulating the intestinal immune system. Furthermore, we also summarize recent advances in the field of new drugs that target bile acid signaling and highlight the importance of bile acids as a new target for disease intervention.


2005 ◽  
Vol 64 (4) ◽  
pp. 451-457 ◽  
Author(s):  
M. Bailey ◽  
K. Haverson ◽  
C. Inman ◽  
C. Harris ◽  
P. Jones ◽  
...  

The mucosal immune system fulfils the primary function of defence against potential pathogens that may enter across vulnerable surface epithelia. However, a secondary function of the intestinal immune system is to discriminate between pathogen-associated and ‘harmless’ antigens, expressing active responses against the former and tolerance to the latter. Control of immune responses appears to be an active process, involving local generation of IgA and of regulatory and/or regulated T lymphocytes. Two important periods of maximum exposure to novel antigens occur in the young animal, immediately after birth and at weaning. In both cases the antigenic composition of the intestinal contents can shift suddenly, as a result of a novel diet and of colonisation by novel strains and species of bacteria. Changes in lifestyles of man, and husbandry of animals, have resulted in weaning becoming much more abrupt than previously in evolution, increasing the number of antigens that must be simultaneously evaluated by neonates. Thus, birth and weaning are likely to represent hazard and critical control points in the development of appropriate responses to pathogens and harmless dietary and commensal antigens. Neonates are born with relatively undeveloped mucosal immune systems. At birth this factor may prevent both expression of active immune responses and development of tolerance. However, colonisation by intestinal flora expands the mucosal immune system in antigen-specific and non-specific ways. At weaning antibody to fed proteins can be detected, indicating active immune responses to fed proteins. It is proposed that under normal conditions the ability of the mucosal immune system to mount active responses to foreign antigens develops simultaneously with the ability to control and regulate such responses. Problems arise when one or other arm of the immune system develops inappropriately, resulting in inappropriate effector responses to harmless food proteins (allergy) or inadequate responses to pathogens (disease susceptibility).


2021 ◽  
Vol 218 (5) ◽  
Author(s):  
Yuhao Li ◽  
Scott A. Handley ◽  
Megan T. Baldridge

The diverse enteric viral communities that infect microbes and the animal host collectively constitute the gut virome. Although recent advances in sequencing and analysis of metaviromes have revealed the complexity of the virome and facilitated discovery of new viruses, our understanding of the enteric virome is still incomplete. Recent studies have uncovered how virome–host interactions can contribute to beneficial or detrimental outcomes for the host. Understanding the complex interactions between enteric viruses and the intestinal immune system is a prerequisite for elucidating their role in intestinal diseases. In this review, we provide an overview of the enteric virome composition and summarize recent findings about how enteric viruses are sensed by and, in turn, modulate host immune responses during homeostasis and disease.


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