immunity · Mechanism Report
Do Lactobacillus species support mucosal immune tolerance?
Lactobacillus species support mucosal immune tolerance by promoting regulatory T-cell signaling, anti-inflammatory pathways, and balanced secretory IgA responses.
This is what AI claimed
Lactobacillus species support mucosal immune tolerance by promoting regulatory T-cell and anti-inflammatory signaling and balanced secretory IgA responses.
Executive summary
The claim describes Lactobacillus species as contributors to gut immune homeostasis rather than as direct anti-inflammatory agents alone. The mechanism framing links tolerogenic dendritic cell activity with regulatory T-cell expansion, anti-inflammatory cytokine signaling, and secretory IgA feedback that helps stabilize tolerance.
Verified conclusion
Lactobacillus species actively maintain gut homeostasis by orchestrating both the cellular and humoral arms of the mucosal immune system.
Mechanistic pathways of tolerance
- Tolerogenic Dendritic Cell Induction: Lactobacillus strains (including L. reuteri, L. casei, and L. rhamnosus) program mucosal dendritic cells (DCs) into a tolerogenic phenotype. This state is characterized by low expression of co-stimulatory markers and elevated levels of retinaldehyde dehydrogenase-2 (RALDH2), COX-2, and IDO.
- Regulatory T-Cell Expansion: These conditioned tolerogenic DCs utilize IL-10, TGF-beta, and retinoic acid to drive the differentiation and expansion of suppressive CD4+ FoxP3+ regulatory T cells (Tregs) within the mesenteric lymph nodes and Peyer's patches.
- Anti-Inflammatory Cytokine Shift: This signaling network shifts the local microenvironment by upregulating key regulatory cytokines (IL-10 and TGF-beta) while concurrently suppressing pro-inflammatory cytokines (TNF-alpha, IL-1beta, and IFN-gamma), which helps sustain the epithelial barrier.
Humoral and cellular feedback loops
- Secretory IgA Production: Stimulated by mucosal TGF-beta, IL-10, and IL-6, B cells undergo class-switching to increase secretory IgA (sIgA) production, establishing non-inflammatory immune exclusion of luminal antigens.
- Symbiotic Reinforcement: The generated sIgA coats mucosal Lactobacilli. These sIgA-bacteria complexes bind to Peyer’s patch DCs, establishing a feedback loop that further amplifies tolerogenic DC programming and subsequent Treg expansion.
Bottom line
Lactobacillus species drive mucosal immune tolerance through a coordinated loop where anti-inflammatory cytokine signaling and tolerogenic dendritic cells expand suppressive FoxP3+ regulatory T cells, while balanced secretory IgA responses feedback to reinforce and stabilize this tolerogenic state.
References
- Postbiotic Lactobacillus sakei CVL-001 promotes mucosal tolerance via NOD2-dependent programming of tolerogenic CD11c+ antigen-presenting cells. — linkinghub.elsevier.com
- Immunomodulatory mechanisms of lactobacilli - PubMed Central — pmc.ncbi.nlm.nih.gov
- A Lactobacillus rhamnosus Strain Induces a Heme Oxygenase Dependent Increase in Foxp3+ Regulatory T Cells — pmc.ncbi.nlm.nih.gov
- Induction of Lupus T Cell Subset by Probiotics‐Matured Tolerogenic Dendritic Cells — onlinelibrary.wiley.com
- Selective probiotic bacteria induce IL-10-producing regulatory T ... — pubmed.ncbi.nlm.nih.gov
- Secretory IgA in complex with Lactobacillus rhamnosus ... — pubmed.ncbi.nlm.nih.gov
- Gut microbiota in regulatory T cell generation and function: mechanisms and health implications — tandfonline.com
- A Lactobacillus rhamnosus Strain Induces a Heme Oxygenase Dependent Increase in Foxp3+ Regulatory T Cells — journals.plos.org
- Secretory IgA in complex with Lactobacillus rhamnosus potentiates mucosal dendritic cell-mediated Treg cell differentiation via TLR regulatory proteins, RALDH2 and secretion of IL-10 and TGF-β - Cellular & Molecular Immunology — nature.com
- Oral administration of Lactobacillus delbrueckii UFV-H2b20 protects mice against Aspergillus fumigatus lung infection — link.springer.com
- Lactobacillus paracasei KBL382 administration attenuates atopic dermatitis by modulating immune response and gut microbiota — tandfonline.com
- Probiotics increase T regulatory cells and reduce severity of experimental colitis in mice. — wjgnet.com
- Lactobacillus spp. for Gastrointestinal Health - PMC - NIH — pmc.ncbi.nlm.nih.gov
- Probiotics, Prebiotics and Immunomodulation of Gut Mucosal Defences: Homeostasis and Immunopathology — ncbi.nlm.nih.gov
- Importance of IL-10 Modulation by Probiotic Microorganisms ... — pmc.ncbi.nlm.nih.gov
- 81 — jstage.jst.go.jp
- Study of the possible mechanisms involved in the mucosal immune ... — pubmed.ncbi.nlm.nih.gov
- In vivo dose response and in vitro mechanistic analysis of enhanced immunoglobulin A production by Lactobacillus plantarum AYA — ncbi.nlm.nih.gov
- Prevention of Atopic Dermatitis in Mice by Lactobacillus Reuteri Fn041 Through Induction of Regulatory T Cells and Modulation of the Gut Microbiota. — onlinelibrary.wiley.com
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