Homeostatic impact of indigenous microbiota and secretory immunity

2010 ◽  
Vol 1 (3) ◽  
pp. 211-227 ◽  
Author(s):  
P. Brandtzaeg
Keyword(s):  
Immune System ◽  
Oral Tolerance ◽  
Treg Cells ◽  
Commensal Bacteria ◽  
Secretory Iga ◽  
Epithelial Barrier ◽  
Food Proteins ◽  
Igm Antibodies ◽  
Indigenous Microbiota ◽  
Induced Tolerance

In the process of evolution, the mucosal immune system has generated two layers of anti-inflammatory defence: (1) immune exclusion performed by secretory IgA (and secretory IgM) antibodies to modulate or inhibit surface colonisation of microorganisms and dampen penetration of potentially dangerous antigens; and (2) suppressive mechanisms to avoid local and peripheral hypersensitivity to innocuous antigens, particularly food proteins and components of commensal bacteria. When induced via the gut, the latter phenomenon is called 'oral tolerance', which mainly depends on the development of regulatory T (Treg) cells in mesenteric lymph nodes to which mucosal dendritic cells (DCs) carry exogenous antigens and become conditioned for induction of Treg cells. Mucosally induced tolerance appears to be a rather robust adaptive immune function in view of the fact that large amounts of food proteins pass through the gut, while overt and persistent food allergy is not so common. DCs are 'decision makers' in the immune system when they perform their antigen-presenting function, thus linking innate and adaptive immunity by sensing the exogenous mucosal impact (e.g. conserved microbial molecular patterns). A balanced indigenous microbiota is required to drive the normal development of both mucosa-associated lymphoid tissue, the epithelial barrier with its secretory IgA (and IgM) system, and mucosally induced tolerance mechanisms including the generation of Treg cells. Notably, polymeric Ig receptor (pIgR/SC) knock-out mice that lack secretory IgA and IgM antibodies show reduced epithelial barrier function and increased uptake of antigens from food and commensal bacteria. They therefore have a hyper-reactive immune system and show predisposition for systemic anaphylaxis after sensitisation; but this development is counteracted by enhanced oral tolerance induction as a homeostatic back-up mechanism.

Oral tolerance and Treg cells are induced in BALB/c mice after gavage with bovine β-lactoglobulin

Allergy ◽  
2011 ◽  
Vol 66 (10) ◽  
pp. 1312-1321 ◽  
Author(s):  
K. Adel-Patient ◽  
S. Wavrin ◽  
H. Bernard ◽  
N. Meziti ◽  
S. Ah-Leung ◽  
...  
Keyword(s):  
Oral Tolerance ◽  
Treg Cells ◽  
Β Lactoglobulin

scholarly journals In Schizophrenia, Increased Plasma Igm/Iga Responses to Gut Commensal Bacteria are Associated with Negative Symptoms, Neurocognitive Impairments and the Deficit Phenotype

2018 ◽  
Author(s):  
Michael Maes ◽  
Buranee Kanchanatawan ◽  
Sunee Sirivichayakul ◽  
Andre F. Carvalho
Keyword(s):  
Azelaic Acid ◽  
Negative Symptoms ◽  
Commensal Bacteria ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Deficit Syndrome ◽  
Igm Antibodies ◽  
Deficit Schizophrenia ◽  
Neurocognitive Impairments ◽  
Natural Igm

Increased gut permeability (leaky gut) with increased translocation of Gram-negative bacteria plays a role in the gut-brain axis through effects on systemic immune-inflammatory processes. Deficit schizophrenia is characterized by an immune-inflammatory response combined with a deficit in natural IgM antibodies to oxidative specific epitopes (OSEs), which are a first line defense against bacterial infections. This study measured plasma IgA/IgM responses to 5 Gram-negative bacteria in association with IgM responses to malondialdehyde (MDA) and azelaic acid in 80 schizophrenia patients (40 with the deficit syndrome and 40 without) and in 38 healthy controls.Deficit schizophrenia was characterized by significantly increased IgA responses to Hafnei alvei, Pseudomonas aeruginosa, Morganella morganii and Klebsiella pneumoniae as compared with non-deficit schizophrenia. The presence of deficit schizophrenia was highly predicted by increased IgA responses to Pseudomonas putida and IgM responses to all 5 Gram-negative bacteria and lowered natural IgM to MDA and azelaic acid with a bootstrap area under the ROC curve of 0.960 (2000 random curves). A large proportion of the variance (41.5%) in the PANSS negative score was explained by the regression on IgA responses to K. pneumoniae and IgM responses to the 5 enterobacteria coupled with lowered IgM antibodies to azelaic acid. There were significant associations between IgA levels to Gram-negative bacteria and Mini Mental State Examination, Boston naming test, Verbal Fluency and Word List Memory test scores.These findings provide further evidence that deficit schizophrenia is a distinct phenotype of schizophrenia, which is characterized by an increased impact of Gram-negative commensal bacteria coupled with a deficit in natural IgM, pointing to aberrations in B1 cells. It is concluded that increased bacterial translocation and deficits in the compensatory immune-regulatory system (CIRS) may drive negative symptoms and neurocognitive impairments, which are hallmarks of deficit schizophrenia.

scholarly journals Liver X Receptor regulates Th17 and RORγt+ Treg cells by distinct mechanisms

2019 ◽  
Author(s):  
Sara M. Parigi ◽  
Srustidhar Das ◽  
Annika Frede ◽  
Rebeca F. Cardoso ◽  
Kumar Parijat Tripathi ◽  
...  
Keyword(s):  
Lymph Node ◽  
Nuclear Receptors ◽  
Th17 Cells ◽  
Immune Modulation ◽  
Treg Cells ◽  
Liver X Receptor ◽  
Commensal Bacteria ◽  
T Helper ◽  
Mesenteric Lymph ◽  
Th Cell

AbstractThe gastrointestinal microenvironment, dominated by dietary compounds and the commensal bacteria, is a major driver of intestinal CD4+ T helper (Th) cell differentiation. Dietary compounds can be sensed by nuclear receptors (NRs) that consequently exerts pleiotropic effects including immune modulation. However, how NRs regulate distinct intestinal Th subsets remain poorly understood. Here, we found that under homeostatic condition Liver X receptor (LXR), a sensor of cholesterol metabolites, controls RORγt+ Treg and Th17 cells in the intestine draining mesenteric lymph node (MLN). Mechanistically, while lack of LXR signaling in CD11c+ myeloid cells led to an increase in RORγt+ Treg, modulation of MLN Th17 was independent of LXR signaling in either immune or epithelial cells. Of note, LXRα modulated only the Th17 cells, but not RORγt+ Treg in the MLN and horizontal transfer of microbiota between LXRα−/− and WT mice was sufficient to partially increase the MLN Th17 in WT mice. While LXRα deficiency increased the abundance of Ruminococcaceae and Lachnospiraceae bacterial families compared to the WT littermates, microbiota ablation including ablation of SFB was not sufficient to dampen LXRα-mediated expansion of MLN Th17. Altogether, our results suggest that LXR modulates RORγt+ Treg and Th17 cells in the MLN through distinct mechanisms.

scholarly journals Commensal Bacteria-Dependent Indole Production Enhances Epithelial Barrier Function in the Colon

PLoS ONE ◽  
2013 ◽  
Vol 8 (11) ◽  
pp. e80604 ◽  
Author(s):  
Yosuke Shimada ◽  
Makoto Kinoshita ◽  
Kazuo Harada ◽  
Masafumi Mizutani ◽  
Kazunori Masahata ◽  
...  
Keyword(s):  
Barrier Function ◽  
Commensal Bacteria ◽  
Epithelial Barrier ◽  
Epithelial Barrier Function ◽  
Indole Production

scholarly journals Effects of Early Nutrition and Sanitary Conditions on Oral Tolerance and Antibody Responses in Broiler Chickens

2020 ◽  
Vol 7 (4) ◽  
pp. 148 ◽  
Author(s):  
Maarten S. Hollemans ◽  
Ger de Vries Reilingh ◽  
Sonja de Vries ◽  
Henk K. Parmentier ◽  
Aart Lammers
Keyword(s):  
Immune System ◽  
Growth Performance ◽  
Broiler Chickens ◽  
Oral Tolerance ◽  
Feeding Strategy ◽  
Later Life ◽  
Antibody Responses ◽  
Oral Exposure ◽  
Antibody Levels ◽  
Sanitary Conditions

Greater antigenic exposure might accelerate activation and maturation of the humoral immune system. After hatch, commercial broiler chickens can have early (EN) or delayed (DN) access to nutrition, up to 72 h after hatch. The immune system of EN versus DN broilers is likely more exposed to antigens after hatch. This might contribute to activation and maturation of the immune system, but might also influence the development of oral tolerance, thereby altering later life antibody responses. We studied antibody (IgM, IgY, IgA) responses between 21 and 42 d of age in fast-growing EN and DN broilers, kept under low (LSC) or high sanitary conditions (HSC). In a first experiment (n = 51 broilers), we tested whether early oral exposure to bovine serum albumin (BSA) affected later life antibody responses towards BSA and a novel antigen—rabbit γ-globulin (RGG), under HSC. In a second experiment, a total of 480 EN and DN broilers were housed under either LSC or HSC, and we studied antibody responses against both BSA and RGG (n = 48 broilers per treatment) and growth performance. Broilers kept under LSC versus HSC, had higher antibody levels and their growth performance was severely depressed. Interactions between feeding strategy (EN versus DN) and sanitary conditions, or main effects of feeding strategy, on natural and specific antibody levels, and growth performance were not observed. Levels of IgA were elevated in EN versus DN broilers, in experiment I and in batch 2 of experiment II, but not in the other batches of experiment II. We concluded that EN versus DN contributes minimally to the regulation of antibody responses, irrespective of antigenic pressure in the rearing environment.

scholarly journals Oral Microbial Ecology and the Role of Salivary Immunoglobulin A

1998 ◽  
Vol 62 (1) ◽  
pp. 71-109 ◽  
Author(s):  
Harold Marcotte ◽  
Marc C. Lavoie
Keyword(s):  
Immune System ◽  
Oral Cavity ◽  
Microbial Ecology ◽  
Periodontal Diseases ◽  
Immunoglobulin A ◽  
Basic Knowledge ◽  
Oral Microbiota ◽  
Indigenous Bacteria ◽  
Indigenous Microbiota

SUMMARY In the oral cavity, indigenous bacteria are often associated with two major oral diseases, caries and periodontal diseases. These diseases seem to appear following an inbalance in the oral resident microbiota, leading to the emergence of potentially pathogenic bacteria. To define the process involved in caries and periodontal diseases, it is necessary to understand the ecology of the oral cavity and to identify the factors responsible for the transition of the oral microbiota from a commensal to a pathogenic relationship with the host. The regulatory forces influencing the oral ecosystem can be divided into three major categories: host related, microbe related, and external factors. Among host factors, secretory immunoglobulin A (SIgA) constitutes the main specific immune defense mechanism in saliva and may play an important role in the homeostasis of the oral microbiota. Naturally occurring SIgA antibodies that are reactive against a variety of indigenous bacteria are detectable in saliva. These antibodies may control the oral microbiota by reducing the adherence of bacteria to the oral mucosa and teeth. It is thought that protection against bacterial etiologic agents of caries and periodontal diseases could be conferred by the induction of SIgA antibodies via the stimulation of the mucosal immune system. However, elucidation of the role of the SIgA immune system in controlling the oral indigenous microbiota is a prerequisite for the development of effective vaccines against these diseases. The role of SIgA antibodies in the acquisition and the regulation of the indigenous microbiota is still controversial. Our review discusses the importance of SIgA among the multiple factors that control the oral microbiota. It describes the oral ecosystems, the principal factors that may control the oral microbiota, a basic knowledge of the secretory immune system, the biological functions of SIgA, and, finally, experiments related to the role of SIgA in oral microbial ecology.

Induction of Oral Tolerance in the Primed Immune System: Influence of Antigen Persistence and Adjuvant Form

2000 ◽  
Vol 202 (2) ◽  
pp. 71-78 ◽  
Author(s):  
Andrew J. Leishman ◽  
Paul Garside ◽  
Allan McI. Mowat
Keyword(s):  
Immune System ◽  
Oral Tolerance ◽  
Antigen Persistence

scholarly journals Regulatory T Cells, a Potent Immunoregulatory Target for CAM Researchers: The Ultimate Antagonist (I)

2006 ◽  
Vol 3 (1) ◽  
pp. 25-30 ◽  
Author(s):  
Aristo Vojdani ◽  
Jonathan Erde
Keyword(s):  
T Cells ◽  
Immune System ◽  
Regulatory T Cells ◽  
Host Defense ◽  
Western Medicine ◽  
Treg Cells ◽  
Active Suppression ◽  
Beneficial Effects ◽  
The Past ◽  
Powerful Means

Over the past decade, great interest has been given to regulatory T (Treg) cells. A vast body of evidence has shown the existence and highlighted the importance of Treg cells in the active suppression of immune system responses. This form of immunoregulation is the dominant means utilized by the immune system to reach a harmony between reciprocal response processes in order to ensure adequate host defense with minimal host detriment. Therapeutically targeting Treg cells is a direct and powerful means to manipulate the immune system to achieve beneficial effects on various disease pathologies, including allergy, autoimmunity and cancer, as well as the facilitation of organ transplantation. This powerful target for immunoregulation is of much concern to practitioners and researchers of complementary and alternative medicine because it allows a great deal of control and certainty in dealing with the prevalence of debilitating immune system-related disorders for which there has been little remedy outside of Western Medicine.

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