Regulatory B Cells Research Articles

Regulatory B-Cells Are Associated Negatively With Regulatory T-Cells and Positively With Cytokines in Peripheral Blood of Pregnant Women.

Regulatory B-cells (Bregs, CD19+CD24hiCD38hi) are a specialized B-cell subset that suppresses immune responses and potentially contribute to the maintenance of an immune-privileged environment for fetal development during pregnancy. However, little is known about the surrounding immunological environment of Bregs in gestational physiology. The relationship of regulatory T-cells (Tregs, CD4+CD25hiCD127loFoxP3+) to Bregs in coordinating immunoregulation during pregnancy is unknown. We aimed to determine whether peripheral concentrations of Bregs and/or PD-L1-expressing Bregs correlated with Tregs and cytokines during pregnancy. Peripheral blood samples were obtained from 29 pregnant women at mean 12 weeks' gestation. Participants were age ≥ 18, self-identified as Latina/Hispanic, and N = 12 primigravid. Peripheral blood mononuclear cells were isolated, stained, and analyzed by flow cytometry to determine percentages of Tregs from CD4+ T-cells and five Treg subsets defined by immune checkpoint markers, and Bregs and PD-L1+ Bregs from total B-cells. Levels of 13 cytokines were measured on a Meso Scale Discovery multiplex platform. Bregs positively correlated with pro-inflammatory cytokine interleukin (IL)-6. PD-L1+ Bregs positively correlated with T-cell suppressive cytokine IL-10. PD-L1+ Bregs negatively correlated with Tregs and Helios+, CTLA-4+, PD-1+, TIGIT+, and TIM3+ Tregs. For primigravida, PD-L1+ Bregs correlated positively with IL-10 and negatively with Helios+ and TIGIT+ Tregs. For multigravida, PD-L1+ Bregs correlated positively with IL-8 and negatively with Helios+, CTLA-4+, PD-1+, and TIGIT+ Tregs. This study provides insight into the immunosuppressive role of Bregs and PD-L1+ Bregs during human pregnancy. Our results suggest that PD-L1+ Bregs can employ suppressive mechanisms to limit pro-inflammatory responses in primigravida.

Microscopic colitis as pre-inflammatory bowel disease model: from early-stage to tissular endpoint fibrosis

Abstract Background and aims Inflammatory bowel disease (IBD) cause chronic relapsing-remitting inflammatory flares in the gastrointestinal tract, resulting in abdominal pain, diarrhea, and gut dysmotility in non-destructive collagenous and lymphocytic microscopic colitis. In addition, classic IBDs Crohn´s disease and ulcerative colitis cause bloody diarrhea and extraintestinal symptoms. Non-destructive IBDs seem to restrain an overt immune response that will damage the tissue and impair wound healing. Thus, I will work under the premise that non-destructive IBDs are undeveloped forms of classic IBDs. Methods First, I aim to deeply characterize and compare immune cells and their activation levels in all forms of IBD using “immunomics” (spectral/computational cytometry) and validate my previous finding of two subtypes of lymphocytic colitis. To identify the microbiota that adheres to intestinal epithelial cell (IEC) and therefore alter permeability, and induce collagen deposition, I will coculture IEC and fibroblasts in organ-on-a-chip platforms to mimic gut conditions, including microflow shear stress. I will stimulate chips with patient-derived microbiota-containing luminal content or homogenized biopsies and resections from collagenous colitis (characterized by pathogenic collagen position) and intestinal fibrosis (a major, irreversible IBD complication that increases mortality), respectively, and study using different sequencing techniques. Of note, collagenous colitis could resemble early stages of intestinal fibrosis. My third objective aims to test my previous observation that regulatory B-cells in collagenous colitis might be responsible of restricting overt inflammation. Anticipated impact I will adapt spectral cytometry panels to characterize the state of mucosal B- and plasma cells. The support of my host, the well-established IBD immunologist Assoc. Prof. David Bernardo at the Institute of Biomedicine and Molecular Genetics (Valladolid, Spain, h-index=33) and me as coordinator of the biobank for the European Microscopic Colitis Group, ensure the feasibility to complete my ambitious research agenda and make a great impact on IBD field to discover disease-specific biomarkers, pathomechanisms, and new druggable targets.

Differentiating multiple sclerosis with predominant spinal cord and optic nerve involvement from other autoimmune demyelinating diseases using B cell immunophenotyping and gene expression profiling.

Multiple sclerosis (MS) may present with predominant involvement of the spinal cord and optic nerve (MS/w-SCON) and mimic other autoimmune inflammatory demyelinating disorders (AIDD) such as neuromyelitis optica spectrum disorder (NMOSD), and relapsing inflammatory optic neuritis (RION). Thus, biomarkers are required for effective differential diagnosis of AIDD. Patients with MS/w-SCON (n = 20), MS without involvement of SCON (MS/wo-SCON) (n = 22), NMOSD (n = 16), RION (n = 15) and healthy individuals (n = 21) were included. Peripheral blood cell immunophenotypes were analyzed by flow cytometry and gene expression levels of isolated B cells were assessed by microarray analysis and quantitative real-time PCR. Significantly increased Breg, plasmablast, and plasma cell ratios distinguished MS/w-SCON from other groups. Most differentially expressed B cell genes were subjected to protein-protein interaction yielding a network of 13 immune mediators (IL18, IL18R1, P2RY12, CSF3R, TNFSF4, TNFRSF13C, TNFRSF1A, CCL20, CCL5, CCR4, CCL4L2, CXCL5, CXCL10). CCL4L2 and CCR4 expression levels distinguished MS/w-SCON. IL18/IL18R1 and CCL5 were distinguishing factors for NMOSD and RION, respectively. Peripheral blood B cell expression levels of CCL4L2, CCR4, IL18, IL18R1 and CCL5 are candidate biomarkers for differential diagnosis of AIDD of CNS. Our results substantiate the significance of B cells in the pathogenesis of these disorders.

B cells abnormalities in asthma

Abstract. Asthma is a chronic inflammation in the respiratory tract, which is an abnormal immune response of type I allergic reaction with elevated IgE levels. The abnormality of B cell contributing to asthma development has not been elucidated completely. Recently, data from different research groups showed that both CD27+CD38+ plasmablasts and CD24hiCD38hi transitional B cells are capable to induce the production of IgE antibody. In contrast, Bregs is crucial for inhibiting type 2 inflammation through secreting cytokines IL-10 in asthma patients of both children and adults. With the advancement of high-throughput sequencing and analysis technology in recent years, there has been further displaying of the association between B subgroups and asthma besides Breg and plasmablast subsets. This article briefly summarized the pathogenesis and pathological progression of Breg cells in animal models and patients of asthma, with a particular focus on high-throughput sequencing revealing new mechanisms and diagnostic

The Protective Effect of Esculentoside A on MPL/lpr Mice by Upregulating the Expression of CD19+IL-35+Breg Cells and Interleukin-35

Introduction: Esculentoside A (EsA) is one of the main components of the traditional Chinese medicine Phytolacca esculenta. The possible mechanism of action of EsA in the treatment of lupus nephritis (LN) was explored by observing the effects of EsA on CD19+ IL-35+regulatory B (IL-35+Breg) cells. Methods: Twenty-four MRL/lpr mice were randomly divided into control, EsA, and EsA+IL-12p35 antibody groups. Mice were administered the respective treatments intraperitoneally once a day for 4 weeks. The urine protein/creatinine ratio (UPCR) and blood creatinine (Cr) and IL-35, IL-10, and IL-17 expression levels were measured. Body and spleen weight were measured to calculate the splenic index (SI). Flow cytometry was performed to determine the proportion of CD19+ IL-35+ Breg cells in the spleen. Hematoxylin-eosin and PASM-Masson staining of renal tissues were performed, and the “Austin” acute index (AI) system for LN was determined. Results: The most severe conditions were seen in mice in the control group, with the highest UPCR, Cr, and IL-17 levels and SI and AI scores; the most severe renal histopathology, and the lowest proportion of CD19+ IL-35+ Breg cells and IL-35 and IL-10 levels. This was followed by the EsA+IL-12p35 antibody group. The EsA group had the lowest UPCR, Cr, and IL-17 levels and SI and AI scores; the mildest renal lesions; and the highest proportion CD19+ IL-35+ Breg cells and IL-35 and IL-10 levels. Conclusion: EsA delayed the progression of LN by promoting the proliferation of CD19+ IL-35+ Breg cells, upregulating the expression of IL-35, and decreasing the secretion of IL-17.

Treatment of allergic rhinitis with a mixed Chinese herbal formula via regulatory B cells: A prospective pilot study

Background and aimMixed Chinese herbal formulas (CHFs) are commonly prescribed for allergic rhinitis (AR), but few studies explore their mechanisms. Prior research highlighted the immunomodulatory effects of a specific mixed CHF (Xin-yi-san + Xiao-qing-long-tang + Xiang-sha-liu-jun-zi-tang) in perennial AR by targeting neutrophils, dendritic cells, and CD4+ T lymphocytes. Here, we aimed to investigate the immunomodulatory mechanisms of mixed CHFs in treating AR by examining their effects on regulatory B (Breg) cells as a novel therapeutic approach. Experimental procedureIn this 3-month prospective pilot study, we assessed the immunomodulatory effect of a mixed CHF on patients with perennial AR, comparing the high-IgE (H-IgE; total serum IgE ≥ 200 IU/mL) and low-IgE (L-IgE; total serum IgE < 200 IU/mL) groups. We measured the percentage of Breg cells and expression of CD1d, CD80 and CD86 using flow cytometry after the stimulation of B cells with CHF treatment. We also investigated the effects of mixed CHFs on cytokine expression by co-culturing Breg cells with CD4+CD25- T cells from perennial AR patients. ResultsForty-nine perennial AR patients enrolled, divided into H-IgE and L-IgE groups. Eight patients withdrew and the remaining 41 patients were included in the final analysis. Mixed CHF treatment elevated Breg cell percentages and their surface marker levels, leading to alterations in the cytokine spectra within the co-culture system of Breg cells and T cells from perennial AR patients in the H-IgE group. ConclusionThe results revealed that mixed CHFs exerted immunomodulatory mechanisms through the Breg cells to inhibit allergic reactions in the H-IgE group.

Mesenchymal stem cells for immune modulation in systemic lupus erythematosus: From bench research to clinical applications.

Systemic lupus erythematosus (SLE) is a prevalent autoimmune disease affecting multiple organ systems. Disease progression is inevitable as part of its natural course, necessitating aggressive therapeutic strategies, particularly with the use of immunosuppressants. Long-term use of steroids and other immunosuppressants is associated with significant adverse effects. Mesenchymal stem cells (MSCs) have been shown to modulate the immune response, leading to immunosuppressive effects against self-antigens. MSCs have demonstrated the ability to modulate several immune cell populations, contributing to favorable outcomes in controlling immune and inflammatory conditions. Recent evidence has shown an increase in Treg and Breg cell subsets following MSC administration, along with modulation of other immune cells, including dendritic cells, B cells, and T cells. However, the balance between MSC pro-inflammatory and anti-inflammatory phenotypic activation remains a critical factor in determining therapeutic outcomes. Various covariates also influence the efficacy of MSC therapy. The aim of this study was to provide a comprehensive overview of the utilization of mesenchymal stem cells (MSCs) in SLE treatment, leveraging their immunomodulatory and immunosuppressive capabilities. Understanding the fundamental preclinical effects of MSCs and recent findings from clinical studies may enhance the potential of MSC therapy in the management of SLE patients.

The Immune Regulatory Functions in B Cells Are Restored by CpG to Reduce Experimental Food Allergy.

Dysfunctional immune regulation contributes to the pathogenesis of food allergy (FA). The mechanism behind regulatory B-cell dysfunction is unclear. CpG has immune regulatory functions. The purpose of this study is to use CpG to recover the immune suppressive functions of B cells in mice with FA. An FA mouse model was created using ovalbumin as the specific antigen. Flow cytometry was used to isolate B cells from the intestinal tissues. The immune regulatory functions of B cells were assessed using immunological approaches. The results showed that the FA response was linked to low IL-10 levels in gut lavage fluids of FA mice. FA mouse intestinal B cells produced lower amounts of IL-10 as compared with B cells isolated from naïve control mice. Impaired immune suppressive functions were observed in B cells isolated from the FA mouse intestine. The inducibility of the Il10 expression in naïve B cells of the intestine of FA mice was defective. The induction of Il10 expression in FA B cells could be restored by CpG through regulating the methylation status of the Cmip promoter. CpG promoted the therapeutic efficacy of allergen specific immunotherapy by restoring the induction of IL-10+ B cells in the intestine. The expression of Il10 in B cells of the FA mouse intestine was impaired. Administration of CpG could restore the expression of Il10 in B cells in the intestine and promote immunotherapy for FA.

Human Ascaris infection is associated with higher frequencies of IL-10 producing B cells.

Ascaris lumbricoides has dual effects on the immune system of infected hosts. The IgE response to this parasite has been thoroughly studied, but little is known about cellular responses induced by infection. This study aims to explore the interplay between A. lumbricoides infection and B cell responses, especially B regulatory cells. Participants from Santa Catalina, Bolívar, Colombia, a helminth-endemic town, were screened for soil-transmitted helminthiasis (STH) using stool examinations. Eighteen A. lumbricoides-infected and 11 non-infected subjects were selected. Blood samples were analyzed for Breg cells and related cytokines, and immunoglobulins specific to the A. lumbricoides excretory/secretory product, ABA-1. Infected subjects exhibited higher frequencies of Breg cells, especially those with a higher A. lumbricoides egg burden. Higher frequencies of different Breg subsets were observed in infected individuals, with CD25+CD71+CD73- B cells being notably increased in strongly infected individuals. Additionally, A. lumbricoides infection was associated with reduced levels of circulating ABA-1-specific IgG1 and IgE. IL-10+ B cell frequencies correlated inversely with ABA-1-specific IgE. A. lumbricoides infection has a significant impact on the immune response, particularly on Breg cell populations and antibody responses. Our findings suggest that A. lumbricoides infection mediates a dose-dependent immunosuppressive response characterized by an increase in Breg cells and concomitant suppression of ABA-1-specific humoral responses.

The iNKT cell ligand α-GalCer prevents murine septic shock by inducing IL10-producing iNKT and B cells.

α-galactosylceramide (α-GalCer), a prototypical agonist of invariant natural killer T (iNKT) cells, stimulates iNKT cells to produce various cytokines such as IFNγ and IL4. Moreover, repeated α-GalCer treatment can cause protective or pathogenic outcomes in various immune-mediated diseases. However, the precise role of α-GalCer-activated iNKT cells in sepsis development remains unclear. To address this issue, we employed a lipopolysaccharide (LPS)/D-galactosamine (D-GalN)-induced murine sepsis model and two alternative models. Sepsis was induced in wild-type (WT) C57BL/6 (B6) mice by three methods (LPS/D-GalN, α-GalCer/D-GalN, and cecal slurry), and these mice were monitored for survival rates. WT B6 mice were intraperitoneally injected with α-GalCer or OCH (an IL4-biased α-GalCer analog) one week prior to the induction of sepsis. To investigate the effects of α-GalCer-mediated iNKT cell activation on sepsis development, immune responses were analyzed by flow cytometry using splenocytes and liver-infiltrating leukocytes. In addition, a STAT6 inhibitor (AS1517499) and an IL10 inhibitor (AS101) were employed to evaluate the involvement of IL4 or IL10 signaling. Furthermore, we performed B cell adoptive transfers to examine the contribution of α-GalCer-induced regulatory B (Breg) cell populations in sepsis protection. In vivo α-GalCer pretreatment polarized iNKT cells towards IL4- and IL10-producing phenotypes, significantly attenuating LPS/D-GalN-induced septic lethality in WT B6 mice. Furthermore, α-GalCer pretreatment reduced the infiltration of immune cells to the liver and attenuated pro-inflammatory cytokine production. Treatment with a STAT6 inhibitor was unable to modulate disease progression, indicating that IL4 signaling did not significantly affect iNKT cell-mediated protection against sepsis. This finding was confirmed by pretreatment with OCH, which did not alter sepsis outcomes. However, interestingly, prophylactic effects of α-GalCer on sepsis were significantly suppressed by treatment with an IL10 antagonist, suggesting induction of IL10-dependent anti-inflammatory responses. In addition to IL10-producing iNKT cells, IL10-producing B cell populations were significantly increased after α-GalCer pretreatment. Overall, our results identify α-GalCer-mediated induction of IL10 by iNKT and B cells as a promising option for controlling the pathogenesis of postoperative sepsis.

Evaluation of Regulatory B Cells and Serum IL-10 Concentration in Peripheral Blood of Women with Recurrent Pregnancy Loss

Background: Although the role of B cells in normal pregnancy has been recently highlighted, their importance and function are not completely clarified. Until now, some investigations have shown that during pregnancy, regulatory B cells (Breg), a subset of B cells, are one of the key players in immune regulation by both producing IL-10 and cell-cell interactions. Therefore, any decrease in the number or function of these cells may lead to recurrent pregnancy loss (RPL). Thus, the objective of this study was to characterize Breg cell frequency and function in women who suffered from RPL in comparison with healthy non-pregnant and pregnant women (under twenty weeks of gestational age) as controls. Method: In this study, peripheral blood samples of women suffering from RPL (n=8), women with normal pregnancy under 20 weeks of gestational age (n=14), and healthy nonpregnant women (n=10) were collected. The frequency of Breg cells (CD19+CD24hiCD38hi) was measured by flow cytometry. The serum level of the IL-10 cytokine, as a marker of Breg cell function, was measured by ELISA. Results: The Percentage of Breg cells in women who suffered from RPL was significantly lower than that of women who had normal pregnancies (P=0.0016). The percentages of Breg cells in women who suffered from RPL were also significantly lower than in non-pregnant women (P=0.0001). Furthermore, no significant differences were observed in Breg cell percentages between normal pregnant and non-pregnant women. Evaluation of IL-10 concentration in the serum of women who had participated in this study showed no significant differences between the three groups. Conclusion: Based on our results, the number of Breg cells was significantly lower in RPL women than in healthy non-pregnant and normal-pregnant women, which shows the significance of these cells in the maintenance of normal pregnancy. However, we could not detect significant differences in the serum levels of IL-10, bringing to mind the notion that the beneficial and supportive function of these cells during pregnancy might be independent of IL-10 secretion. by these cells. Thus, screening of Breg cells in women with pregnancy complications, especially RPL, could be helpful for predicting a healthy pregnancy.

Immunoinhibitory effects of hypoxia-driven reprogramming of EGR1hi and EGR3 positive B cells in the nasopharyngeal carcinoma microenvironment

Regulatory B (Breg) cells is a type of immune cell that exhibit immunosuppressive behavior within the tumor microenvironment. However, the differentiation and regulatory mechanisms of these Breg cells remain unexplored. Single-cell transcriptome sequencing analysis of human nasopharyngeal carcinoma (NPC) revealed a significant enrichment of B cell subset characterized by high expression of EGR1 and EGR3 in the tumor microenvironment. Notably, in the hypoxic microenvironment, these B cells induce MAPK pathway activation, subsequently triggering the activation of transcription factors EGR1 and EGR3, which further modulate the expression of immunosuppressive factors like TGFB1 and IL10. In transplant experiments using primary B cells induced under hypoxia and co-transplanted with cancer cells, a significant increase in tumor growth was observed. Mechanism experiments demonstrated that EGR1hi and EGR3+ B cells further activate the maturation and immunosuppressive function of Treg cells through the secretion of IL16 and TNF-α. Hence, this study identifies the key transcription factors EGR1 and EGR3 as essential regulators and elucidates the differentiation of Breg cells under hypoxic conditions.

Multi-dimensional analysis of B cells reveals the expansion of memory and regulatory B-cell clusters in humans living in rural tropical areas.

B-cells play a critical role in the formation of immune responses against pathogens by acting as antigen-presenting cells, by modulating immune responses, and by generating immune memory and antibody responses. Here, we studied B-cell subset distributions between regions with higher and lower microbial exposure, i.e. by comparing peripheral blood B-cells from people living in Indonesia or Ghana to those from healthy Dutch residents using a 36-marker mass cytometry panel. By applying an unbiased multidimensional approach, we observed differences in the balance between the naïve and memory compartments, with higher CD11c+ and double negative (DN-IgDnegCD27neg) memory (M)B-cells in individuals from rural tropical areas, and conversely lower naïve B-cells compared to residents from an area with less pathogen exposure. Furthermore, characterization of total B-cell populations, CD11c+, DN, and Breg cells showed the emergence of specific memory clusters in individuals living in rural tropical areas. Some of these differences were more pronounced in children compared to adults and suggest that a higher microbial exposure accelerates memory B-cell formation, which "normalizes" with age.

IL-10+ regulatory B cells mitigate atopic dermatitis by suppressing eosinophil activation

Atopic dermatitis (AD) presents significant therapeutic challenges due to its poorly understood etiology. Eosinophilia, a hallmark of allergic inflammation, is implicated in AD pathogenesis. Interleukin-10 (IL-10)-producing regulatory B (Breg) cells exhibit potent anti-inflammatory effects. However, their role in controlling AD-related eosinophilia is not well understood. To investigate the impact of eosinophils on AD, we employed IL-5Rα-deficient (Il5ra−/−) mice, which lack functional eosinophils. Induction of AD in these mice resulted in attenuated disease symptoms, underscoring the critical role of eosinophils in AD development. Additionally, the adoptive transfer of purified Breg cells into mice with AD significantly alleviated disease severity. Mechanistic studies revealed that IL-10 produced by Breg cells directly inhibits eosinophil activation and infiltration into the skin. In vitro experiments further confirmed that Breg cells inhibited eosinophil peroxidase secretion in an IL-10-dependent manner. Our collective findings demonstrate that IL-10 from Breg cells alleviates AD by suppressing eosinophil activation and tissue infiltration. This study elucidates a novel regulatory mechanism of Breg cells, providing a foundation for future Breg-mediated therapeutic strategies for AD.

Inhibition of DNMT1 attenuates experimental food allergy

BackgroundThe treatment of food allergy (FA) needs improvement. The treatment of immune disorders can be improved by regulating epigenetic marks, which is a promising method. The objective of this research is to alleviate experimental FA by employing an inhibitor of DNA methyltransferase-1 (DNMT1). MethodsOvalbumin was used as the specific antigen to establish a mouse model of FA. Intestinal IL-35+ regulatory B cells (Breg cells) were isolated from FA mice, and characterized using immunological approaches. ResultsFA mice had a lower frequency of IL-35+ Breg cells, which was inversely correlated with their FA response. The quantity of IL-35 was lower in intestinal Breg cells from FA mice. Hypermethylation status was detected in the Il35 promoter, which was accompanied with high levels of H3K9me3. Enforced expression of DNMT1 hindered the promoter activity of the IL35 gene. Administration of an inhibitor of DNMT1 (RG108) restored the immune regulatory capacity of FA intestinal Bregs, and effectively suppressed the expression of DNMT1, and attenuated experimental FA. ConclusionsThe elevated quantity of DNMT1 in intestinal Breg cells compromises the expression of IL-35 and affects the immune regulatory functions, which facilitates the development of FA. The immune regulatory functions of intestinal Breg cells are restored and experimental FA is attenuated by inhibiting DNMT1.

Allergen-specific B cell responses in oral immunotherapy-induced desensitization, remission, and natural outgrowth in cow's milk allergy.

Antigen-specific memory B cells play a key role in the induction of desensitization and remission to food allergens in oral immunotherapy and in the development of natural tolerance (NT). Here, we characterized milk allergen Bos d 9-specific B cells in oral allergen-specific immunotherapy (OIT) and in children spontaneously outgrowing cow's milk allergy (CMA) due to NT. Samples from children with CMA who received oral OIT (before, during, and after), children who naturally outgrew CMA (NT), and healthy individuals were received from Stanford biobank. Bos d 9-specific B cells were isolated by flow cytometry and RNA-sequencing was performed. Protein profile of Bos d 9-specific B cells was analyzed by proximity extension assay. Increased frequencies of circulating milk allergen Bos d 9-specific B cells were observed after OIT and NT. Milk-desensitized subjects showed the partial acquisition of phenotypic features of remission, suggesting that desensitization is an earlier stage of remission. Within these most significantly expressed genes, IL10RA and TGFB3 were highly expressed in desensitized OIT patients. In both the remission and desensitized groups, B cell activation-, Breg cells-, BCR-signaling-, and differentiation-related genes were upregulated. In NT, pathways associated with innate immunity characteristics, development of marginal zone B cells, and a more established suppressor function of B cells prevail that may play a role in long-term tolerance. The analyses of immunoglobulin heavy chain genes in specific B cells demonstrated that IgG2 in desensitization, IgG1, IgA1, IgA2, IgG4, and IgD in remission, and IgD in NT were predominating. Secreted proteins from allergen-specific B cells revealed higher levels of regulatory cytokines, IL-10, and TGF-β after OIT and NT. Allergen-specific B cells are essential elements in regulating food allergy towards remission in OIT-received and naturally resolved individuals.

Gut microbiota from B-cell-specific TLR9-deficient NOD mice promote IL-10+ Breg cells and protect against T1D.

Type 1 diabetes (T1D) is an autoimmune disease characterized by the destruction of insulin-producing β cells. Toll-like receptor 9 (TLR9) plays a role in autoimmune diseases, and B cell-specific TLR9 deficiency delays T1D development. Gut microbiota are implicated in T1D, although the relationship is complex. However, the impact of B cell-specific deficiency of TLR9 on intestinal microbiota and the impact of altered intestinal microbiota on the development of T1D are unclear. This study investigated how gut microbiota and the intestinal barrier contribute to T1D development in B cell-specific TLR9-deficient NOD mice. Additionally, this study explored the role of microbiota in immune regulation and T1D onset. The study assessed gut permeability, gene expression related to gut barrier integrity, and gut microbiota composition. Antibiotics depleted gut microbiota, and fecal samples were transferred to germ-free mice. The study also examined IL-10 production, Breg cell differentiation, and their impact on T1D development. B cell-specific TLR9-deficient NOD mice exhibited increased gut permeability and downregulated gut barrier-related gene expression. Antibiotics restored gut permeability, suggesting microbiota influence. Altered microbiota were enriched in Lachnospiraceae, known for mucin degradation. Transferring this microbiota to germ-free mice increased gut permeability and promoted IL-10-expressing Breg cells. Rag-/- mice transplanted with fecal samples from Tlr9 fl/fl Cd19-Cre+ mice showed delayed diabetes onset, indicating microbiota's impact. B cell-specific TLR9 deficiency alters gut microbiota, increasing gut permeability and promoting IL-10-expressing Breg cells, which delay T1D. This study uncovers a link between TLR9, gut microbiota, and immune regulation in T1D, with implications for microbiota-targeted T1D therapies.

#953 Preliminary results of the peripheral T follicular cells and their subsets in ANCA associated glomerulonephritis

Abstract Background and Aims T cells play crucial role in the pathogenesis of autoimmune diseases such as ANCA associated vasculitis-glomerulonephritis (AAV/GN) by secreting immune mediators and helping B cell-mediated long-lived humoral immunity development. Specific T and B cells subsets can be used as biomarkers of patients with AAV/GN. We aimed to prospectively compare the predictive ability of such subpopulations in patients with active AAV/GN. Method Flow cytometry was applied in the peripheral blood of 29 subjects. 15 AAV/GN patients (M/F 6/9), age: 62.1(28-82)years, MPO/PR3/Negative ANCA: 10/4/1) and 14 healthy controls (HC), to estimate T-cells subsets: CD4, T-folicular cells (Tfol), T-regulatory cells (Tregs), Tfh, Tfh1, Tfh2, Tfh17, and T-folicular regulatory cells(Tfr) and B-cells subsets: CD19, IgD(+)CD127(-), IgD(+)CD127(+), IgD(-)CD127(+) and IgD(-)CD127(-). Results Compared to HC, AAV/GN patients had reduced CD4 (698.8 Vs 368.8, p = 0.04) but increased proportion of Tfol, and both Tfh1 and Tfh2 cells (7% vs 12%, p = 0.05, 8.4 vs 11.2, p = 0.03, 13.3 vs. 45.9, p = 0.09, respectively). Both Tfr (p = 0.048) and Tfh (p = 0.023) were also significantly higher in group A, compared to group HC. CD19 levels were lower in AAV/GN compared to HC, with reduced all subpopulation, though of not-statistical significance. Conclusion Specific T-cells subsets can be measured in AAV/GN patients’ peripheral blood. Subpopulations such as Tfh and Tfr can be used as biomarkers to diagnose patients with active disease and their role in the pathogenesis of AAV/GN must be studied in detail to determine if they can become targets for new therapies in the future.

Regulatory B-cells: immunomodulating mechanisms and important cellular targets underlining immunotherapy by immunoregulation

Regulatory B-cells (Breg cells) represent as an important modulator of the immune system and their role is unique in autoimmunity, infection, tolerance to transplants, allergy, and cancer. Several regulatory mechanisms exist by which Breg cells can control the function of other immune cells through two main pathways: the secretion of soluble mole¬cules and the use of cell surface-expressed molecules. Anti-inflammatory cytokine interleukin-10 acts as the hallmark of Breg cell function; other cytokines with a similar role include the transforming growth factor-beta and interleukin-35. Breg B cells also release the cytotoxic granzyme B that mediates cell apoptosis. Cell surface-expressed proteins include FasL, CD80, CD86, CD73, CD1d, and PD-L1. The present article reviews the immunosuppressive pathways in order to understand how they emerge and are induced to evoke their regulatory activities, and how we can benefit from them in the field of immunotherapy.

Naive and regulatory B-cell transcription patterns guide the increased risk of papillary thyroid carcinoma in obesity.

A growing number of studies suggest a positive association between obesity and the high incidence of papillary thyroid cancer (PTC), suggesting that the abnormal levels of adipokines associated with obesity may be a risk factor for these aggressive thyroid cancers, but the underlying regulatory mechanisms are not yet clear. We downloaded bulk RNA sequence data for subcutaneous adipose tissue (SAT) in obesity and healthy population and tumor tissues of PTC from GEO database. Through analysis of Differential Expression Genes (DEGs), Gene Set Variation Analysis (GSVA) and Weighted Correlation Network Analysis (WGCNA), we identified co-expressed genes between obesity and PTC, and their pathways were mainly enriched in the regulation of B-cells. Furthermore, through TCGA-THCA (thyroid carcinoma) cohorts analysis, we identified B-cell regulatory-related genes LEF1, TNFRSF13C, SHLD2 and SHLD3 as independent prognostic markers of PTC. Next, we explored the transcriptional regulation mechanism of the increased risk of PTC in obesity through analysis of DNA methylation CpGs data and single-cell RNA sequences (scRNA-seq) from GEO database. PTC-induced hypomethylation of the promoter region may be involved in the transcriptional regulation of these genes, while these genes were further identified in naive and regulatory B-cells of both diseases. Notably, both of the gene expressions in naive and regulatory B-cells showed high similarity in both diseases. Our data reveals the high frequency of PTC in obese populations may be explained by the comparable transcriptional patterns of naive and regulatory B-cells, and offers novel insights for the analysis of critical genes and underlying biological mechanisms for obesity and PTC.