RESUMO

Food components suppressing small intestinal tumorigenesis are not well-defined partly because of the rarity of this tumor type compared to colorectal tumors. Using Apcmin/+ mice, a mouse model for intestinal tumorigenesis, and antigen-free diet, we report here that food antigens serve this function in the small intestine. By depleting Peyer's patches (PPs), immune inductive sites in the small intestine, we found that PPs have a role in the suppression of small intestinal tumors and are important for the induction of small intestinal T cells by food antigens. On the follicle-associated epithelium (FAE) of PPs, microfold (M) cells pass food antigens from lumen to the dendritic cells to induce T cells. Single-cell RNA-seq (scRNA-seq) analysis of immune cells in PPs revealed a significant impact of food antigens on the induction of the PP T cells and the antigen presentation capacity of dendritic cells. These data demonstrate the role of food antigens in the suppression of small intestinal tumorigenesis by PP-mediated immune cell induction.

Assuntos

Células Dendríticas , Neoplasias Intestinais , Intestino Delgado , Nódulos Linfáticos Agregados , Animais , Camundongos , Intestino Delgado/imunologia , Intestino Delgado/patologia , Neoplasias Intestinais/imunologia , Neoplasias Intestinais/patologia , Neoplasias Intestinais/genética , Nódulos Linfáticos Agregados/imunologia , Células Dendríticas/imunologia , Carcinogênese/imunologia , Antígenos/imunologia , Camundongos Endogâmicos C57BL , Linfócitos T/imunologia , Apresentação de Antígeno/imunologia , Modelos Animais de Doenças , Alimentos

RESUMO

Lentinan (LNT), a natural polysaccharide, has been reported to exhibit immunomodulatory effects in the intestine after oral administration. Herein, we aimed to investigate the lymphatic transport of LNT in Peyer's patches (PPs) by traceable fluorescent labeling and to explore whether/how LNT contacts related immune cells. Near-infrared imaging confirmed the absorption of LNT in the small intestinal segment and its accumulation within PPs after oral administration. Subsequently, tissue imaging confirmed that M cells are the main cells responsible for transporting LNT to PPs, and an M cell model was established to explore the involvement of Dectin-1 in the absorption process. Systematic in vitro and in vivo studies revealed that the Dectin-1 further mediates the uptake of LNT by mononuclear phagocytes in PPs. Moreover, LNT can promote the proliferation and differentiation of mononuclear phagocytes, thereby activating immune responses. In summary, this study elucidates the pharmacokinetic mechanisms by which LNT exerts oral immunomodulatory effects, providing a theoretical basis for the development and application of other polysaccharides.

Assuntos

Lectinas Tipo C , Lentinano , Nódulos Linfáticos Agregados , Nódulos Linfáticos Agregados/imunologia , Nódulos Linfáticos Agregados/efeitos dos fármacos , Nódulos Linfáticos Agregados/metabolismo , Animais , Lentinano/farmacologia , Lentinano/química , Lectinas Tipo C/metabolismo , Camundongos , Administração Oral , Fagócitos/efeitos dos fármacos , Fagócitos/metabolismo , Fagócitos/imunologia , Imunomodulação/efeitos dos fármacos , Masculino , Camundongos Endogâmicos BALB C , Células M

RESUMO

We investigated the influence of a Wnt5A-gut microbiota axis on gut B-cell repertoire and protection from infection, having previously demonstrated that Wnt5A in association with gut commensals helps shape gut T-cell repertoire. Accordingly, Wnt5A heterozygous mice, which express less than wild-type level of Wnt5A, and their isolated Peyer's patches (PPs) were studied in comparison with the wild-type counterparts. The percentages of IgM- and IgA-expressing B cells were quite similar in the PP of both sets of mice. However, the PP of the Wnt5A heterozygous mice harbored significantly higher than wild-type levels of microbiota-bound B cell-secreted IgA, indicating the prevalence of a microbial population therein, which is significantly altered from that of wild-type. Additionally, the percentage of PP IgG1-expressing B cells was appreciably depressed in the Wnt5A heterozygous mice in comparison to wild-type. Wnt5A heterozygous mice, furthermore, exhibited notably higher than the wild-type levels of morbidity and mortality following infection with Salmonella typhimurium, a common gut pathogen. Differences in morbidity/mortality correlated with considerable disparity between the PP-B-cell repertoires of the Salmonella-infected Wnt5A heterozygous and wild-type mice, in which the percentage of IgG1-expressing B1b cells in the PP of heterozygous mice remains significantly low as compared to wild-type. Overall, these results suggest that a gut Wnt5A-microbiota axis is intrinsically associated with the maintenance of gut B-cell repertoire and protection from infection.IMPORTANCEAlthough it is well accepted that B cells and microbiota are required for protection from infection and preservation of gut health, a lot remains unknown about how the optimum B-cell repertoire and microbiota are maintained in the gut. The importance of this study lies in the fact that it unveils a potential role of a growth factor termed Wnt5A in the safeguarding of the gut B-cell population and microbiota, thereby protecting the gut from the deleterious effect of infections by common pathogens. Documentation of the involvement of a Wnt5A-microbiota axis in the shaping of a protective gut B-cell repertoire, furthermore, opens up new avenues of investigations for understanding gut disorders related to microbial dysbiosis and B-cell homeostasis that, till date, are considered incurable.

Assuntos

Linfócitos B , Microbioma Gastrointestinal , Proteína Wnt-5a , Animais , Proteína Wnt-5a/genética , Proteína Wnt-5a/imunologia , Microbioma Gastrointestinal/imunologia , Camundongos , Linfócitos B/imunologia , Nódulos Linfáticos Agregados/imunologia , Nódulos Linfáticos Agregados/microbiologia , Salmonella typhimurium/imunologia , Salmonella typhimurium/genética , Infecções por Salmonella/imunologia , Infecções por Salmonella/microbiologia , Camundongos Endogâmicos C57BL , Feminino , Masculino , Imunoglobulina A/imunologia , Imunoglobulina G/imunologia

RESUMO

Post-injury dysfunction of humoral immunity accounts for infections and poor outcomes in cardiovascular diseases. Among immunoglobulins (Ig), IgA, the most abundant mucosal antibody, is produced by plasma B cells in intestinal Peyer's patches (PP) and lamina propria. Here we show that patients with stroke and myocardial ischemia (MI) had strongly reduced IgA blood levels. This was phenocopied in experimental mouse models where decreased plasma and fecal IgA were accompanied by rapid loss of IgA-producing plasma cells in PP and lamina propria. Reduced plasma IgG was detectable in patients and experimental mice 3-10 d after injury. Stroke/MI triggered the release of neutrophil extracellular traps (NETs). Depletion of neutrophils, NET degradation or blockade of NET release inhibited the loss of IgA+ cells and circulating IgA in experimental stroke and MI and in patients with stroke. Our results unveil how tissue-injury-triggered systemic NET release disrupts physiological Ig secretion and how this can be inhibited in patients.

Assuntos

Armadilhas Extracelulares , Infarto do Miocárdio , Neutrófilos , Armadilhas Extracelulares/metabolismo , Armadilhas Extracelulares/imunologia , Humanos , Animais , Infarto do Miocárdio/imunologia , Infarto do Miocárdio/patologia , Infarto do Miocárdio/metabolismo , Masculino , Neutrófilos/imunologia , Neutrófilos/metabolismo , Feminino , Modelos Animais de Doenças , Camundongos Endogâmicos C57BL , Acidente Vascular Cerebral/imunologia , Acidente Vascular Cerebral/patologia , Acidente Vascular Cerebral/metabolismo , Nódulos Linfáticos Agregados/imunologia , Nódulos Linfáticos Agregados/patologia , Nódulos Linfáticos Agregados/metabolismo , Imunoglobulina A/metabolismo , Imunoglobulina A/imunologia , Imunoglobulina A/sangue , Idoso , Pessoa de Meia-Idade , Imunoglobulina G/imunologia , Imunoglobulina G/metabolismo , Imunidade Humoral , Estudos de Casos e Controles , Camundongos , Plasmócitos/imunologia , Plasmócitos/metabolismo

RESUMO

In the human and veterinary fields, oral vaccines generate considerable interest. In dogs, these vaccines are newly developed, and understanding their mechanisms is crucial. Mesenteric lymph nodes (MLNs) and Peyer's patches (PPs) are important sites for gastrointestinal mucosal induction, yet canine MLNs lack sufficient information. To address this, we collected MLN samples from healthy dogs, performed flow cytometry to characterize immune cells, and conducted single-cell RNA sequencing (scRNA-seq) to explore subpopulations, particularly B and T lymphocytes. This effort enabled the characterization of canine MLN's main cell populations and the construction of a predictive atlas, as well as the identification of particularities of this area.

Assuntos

Linfonodos , Animais , Cães , Linfonodos/metabolismo , Linfonodos/imunologia , Humanos , Camundongos , Mesentério , Linfócitos B/metabolismo , Linfócitos B/imunologia , Nódulos Linfáticos Agregados/metabolismo , Linfócitos T/imunologia , Linfócitos T/metabolismo , Análise de Célula Única , Análise de Sequência de RNA , Citometria de Fluxo , Masculino , Feminino , Análise da Expressão Gênica de Célula Única

RESUMO

Immunoglobulin A (IgA)-mediated mucosal immunity is important for the host because it contributes to reducing infection risk and to establishing host-microbe symbiosis. BTB and CNC homology 1 (Bach1) is a transcriptional repressor with physiological and pathophysiological functions that are of particular interest for their relation to gastrointestinal diseases. However, Bach1 effects on IgA-mediated mucosal immunity remain unknown. For this study using Bach1-deficient (Bach1-/-) mice, we investigated the function of Bach1 in IgA-mediated mucosal immunity. Intestinal mucosa, feces, and plasma IgA were examined using immunosorbent assay. After cell suspensions were prepared from Peyer's patches and colonic lamina propria, they were examined using flow cytometry. The expression level of polymeric immunoglobulin receptor (pIgR), which plays an important role in the transepithelial transport of IgA, was evaluated using Western blotting, quantitative real-time PCR, and immunohistochemistry. Although no changes in the proportions of IgA-producing cells were observed, the amounts of IgA in the intestinal mucosa were increased in Bach1-/- mice. Furthermore, plasma IgA was increased in Bach1-/- mice, but fecal IgA was decreased, indicating that Bach1-/- mice have abnormal secretion of IgA into the intestinal lumen. In fact, Bach1 deficiency reduced pIgR expression in colonic mucosa at both the protein and mRNA levels. In the human intestinal epithelial cell line LS174T, suppression of Bach1 reduced pIgR mRNA stability. In contrast, the overexpression of Bach1 increased pIgR mRNA stability. These results demonstrate that Bach1 deficiency causes abnormal secretion of IgA into the intestinal lumen via suppression of pIgR expression.NEW & NOTEWORTHY The transcriptional repressor Bach1 has been implicated in diverse intestinal functions, but the effects of Bach1 on IgA-mediated mucosal immunity remain unclear. We demonstrate here that Bach1 deficiency causes abnormal secretion of IgA into the intestinal lumen, although the proportions of IgA-producing cells were not altered. Furthermore, Bach1 regulates the expression of pIgR, which plays an important role in the transepithelial transport of IgA, at the posttranscriptional level.

Assuntos

Fatores de Transcrição de Zíper de Leucina Básica , Mucosa Intestinal , Camundongos Knockout , Receptores de Imunoglobulina Polimérica , Animais , Fatores de Transcrição de Zíper de Leucina Básica/genética , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Fatores de Transcrição de Zíper de Leucina Básica/deficiência , Receptores de Imunoglobulina Polimérica/genética , Receptores de Imunoglobulina Polimérica/metabolismo , Mucosa Intestinal/metabolismo , Mucosa Intestinal/imunologia , Camundongos , Humanos , Imunoglobulina A/metabolismo , Imunidade nas Mucosas , Camundongos Endogâmicos C57BL , Imunoglobulina A Secretora/metabolismo , Nódulos Linfáticos Agregados/metabolismo , Nódulos Linfáticos Agregados/imunologia , Regulação da Expressão Gênica

RESUMO

Introduction: Lrba is a cytoplasmic protein involved in vesicular trafficking. Lrba-deficient (Lrba-/-) mice exhibit substantially higher levels of IgA in both serum and feces than wild-type (WT) mice. Transforming growth factor ß1 (TGFß1) and its receptors (TGFßR I and II) is essential for differentiating IgA+ B cells. Furthermore, increased IgA production suggests a potential connection between Lrba and the TGFßR signaling pathway in IgA production. However, the specific function of Lrba in B cell biology remains unknown. Aim: Given the increased IgA levels in Lrba-/- mice, the goal in this work was to explore the lymph organs where the switch to IgA occurs, and if TGFßR function is affected. Methods: Non-immunized Lrba-/- mice were compared with Lrba+/+ mice. IgA levels in the serum and feces, as well as during peripheral B cell development, were determined. IgA+ B cells and plasma cells were assessed in the small intestine and secondary lymphoid organs, such as the spleen, mesenteric lymph nodes, and Peyer's patches. The TGFßR signaling pathway was evaluated by determining the expression of TGFßR on B cells. Additionally, SMAD2 phosphorylation was measured under basal conditions and in response to recombinant TGFß. Finally, confocal microscopy was performed to investigate a possible interaction between Lrba and TGFßR in B cells. Results: Lrba-/- mice exhibited significantly higher levels of circulating IgA, IgA+ B, and plasma cells than in peripheral lymphoid organs those in WT mice. TGFßR expression on the membrane of B cells was similar in both Lrba-/- and Lrba+/+ mice. However, intracellular TGFßR expression was reduced in Lrba-/- mice. SMAD2 phosphorylation showed increased levels under basal conditions; stimulation with recombinant TGFß elicited a poorer response than in that in Lrba+/+ B cells. Finally, we found that Lrba colocalizes with TGFßR in B cells. Conclusion: Lrba is essential in controlling TGFßR signaling, subsequently regulating SMAD2 phosphorylation on B cells. This mechanism may explain the increased differentiation of IgA+ B cells and production of IgA-producing plasma cells.

Assuntos

Linfócitos B , Diferenciação Celular , Imunoglobulina A , Transdução de Sinais , Animais , Camundongos , Linfócitos B/imunologia , Linfócitos B/metabolismo , Diferenciação Celular/imunologia , Imunoglobulina A/imunologia , Camundongos Endogâmicos C57BL , Camundongos Knockout , Nódulos Linfáticos Agregados/imunologia , Nódulos Linfáticos Agregados/metabolismo , Receptores de Fatores de Crescimento Transformadores beta/metabolismo , Receptores de Fatores de Crescimento Transformadores beta/genética , Proteína Smad2/metabolismo , Proteínas de Transporte Vesicular/genética , Proteínas de Transporte Vesicular/metabolismo

RESUMO

Peyer's patches (PPs), which contain an abundance of B and T cells, play a key role in inducing pivotal immune responses in the intestinal tract. PPs are defined as aggregated lymph follicles, which consist of multiple lymph follicles (LFs) that may interact with each other in a synergistic manner. LFs are thought to be spherical in shape; however, the characteristics of their structure are not fully understood. To elucidate changes in the structure of PPs as individuals grow, we generated serial 2D sections from entire PPs harvested from mice at 2, 4, and 10 weeks of age and performed a 3D analysis using a software, Amira. Although the number of LFs in PPs was not changed throughout the experiment, the volume and surface area of LFs increased significantly, indicating that LFs in PPs develop continuously by recruiting immune cells, even after weaning. In response to the dramatic changes in the intestinal environment after weaning, the development of germinal centers (GCs) in LFs was observed at 4 and 10 weeks (but not 2 weeks) of age. In addition, GCs gradually began to form away from the center of LFs and close to the muscle layer where export lymphatic vessels develop. Importantly, each LF was joined to the adjacent LF; this feature was observed even in preweaning nonactivated PPs. These results suggest that PPs may have a unique organization and structure that enhance immune functions, allowing cells in LFs to have free access to adjacent LFs and egress smoothly from PPs to the periphery upon stimulation after weaning.

Assuntos

Nódulos Linfáticos Agregados , Desmame , Animais , Nódulos Linfáticos Agregados/imunologia , Camundongos , Centro Germinativo/imunologia , Linfócitos B/imunologia , Junções Intercelulares

RESUMO

Although fucoidan has potential use as an anti-inflammatory agent, the specific mechanisms by which it influences signaling and immunomodulatory pathways between gut microbiota and Peyer's patches remain unclear. Therefore, the aim of this study was to investigate the therapeutic potential of fucoidan in a dextran sulfate sodium (DSS)-induced mouse model of inflammatory bowel disease (IBD) by examining the effects on gut microbiota and the underlying anti-inflammatory mechanisms. Purified fucoidan, which upon characterization revealed structural fragments comprising →3)-ß-D-Galp-(1→, →4)-α-L-Fucp-(1→, and →3)-α-L-Fucp-(1→ residues with a sulfation at position C2 was used. Treatment of the mice with fucoidan significantly alleviated the symptoms of IBD and restored the diversity of gut microbiota by enhancing the abundance of Bacteroidetes and reducing the proportion of Firmicutes. The administration of fucoidan also elevated levels of short-chain fatty acids while reducing the levels of pro-inflammatory cytokines, including interleukin (IL)-1ß, IL-6, tumor necrosis factor (TNF)-α, and interferon (IFN)-γ. Most importantly, fucoidan attenuated the expression of integrin α4ß7/MAdCAM-1 and CCL25/CCR9, which are involved in homing intestinal lymphocytes within Peyer's patches. These findings indicate that fucoidan is a promising gut microbiota modulator and an anti-inflammatory agent for IBD.

Assuntos

Sulfato de Dextrana , Microbioma Gastrointestinal , Doenças Inflamatórias Intestinais , Nódulos Linfáticos Agregados , Polissacarídeos , Animais , Microbioma Gastrointestinal/efeitos dos fármacos , Polissacarídeos/farmacologia , Polissacarídeos/química , Nódulos Linfáticos Agregados/efeitos dos fármacos , Nódulos Linfáticos Agregados/imunologia , Camundongos , Doenças Inflamatórias Intestinais/tratamento farmacológico , Doenças Inflamatórias Intestinais/imunologia , Camundongos Endogâmicos C57BL , Citocinas/metabolismo , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/química , Modelos Animais de Doenças , Masculino

RESUMO

Functional M cells are differentiated by receptor activator of NF-κB ligand (RANKL) and capture of luminal antigens to initiate immune responses. We aimed to use postbiotic-based recombinant chicken RANKL (cRANKL) to promote M cell differentiation and test the efficacy of oral vaccines. Chicks were divided into three groups that were administered phosphate-buffered saline (PBS), cell extracts of wild-type Lactococcus lactis subsp. lactis IL1403 (WT_CE), or cell extracts of recombinant L. lactis expressing cRANKL (cRANKL_CE). The expression of the M cell marker was measured, and the gut microbiome was profiled. The efficiency of the infectious bursal disease (IBD) vaccine was tested after 12 consecutive days of administering cRANKL_CE. The chickens that were administered cRANKL_CE (p = 0.038) had significantly higher Annexin A5 (ANXA5) mRNA expression levels than those in the PBS group (PBS vs. WT_CE, p = 0.657). In the gut microbiome analysis, no significant changes were observed. However, the relative abundance of Escherichia-Shigella was negatively correlated (r = - 0.43, p = 0.019) with ANXA5 mRNA expression in Peyer's patches. cRANKL_CE/IBD (p = 0.018) had significantly higher IBD-specific faecal IgA levels than PBS/IBD (PBS/IBD vs. WT_CE/IBD, p = 0.217). Postbiotic-based recombinant cRANKL effectively improved the expression of M cell markers and the efficiency of oral vaccines. No significant changes were observed in the gut microbiome after administration of postbiotic-based recombinant cRANKL. This strategy can be used for the development of feed additives and adjuvants. KEY POINTS: • Postbiotic-based recombinant cRANKL enhanced the expression of ANXA5 in chicken. • The relative abundance of Escherichia-Shigella was negatively correlated with ANXA5 expression. • Postbiotic-based recombinant cRANKL effectively improved the efficiency of oral vaccine.

Assuntos

Galinhas , Microbioma Gastrointestinal , Lactococcus lactis , Ligante RANK , Proteínas Recombinantes , Animais , Galinhas/imunologia , Administração Oral , Lactococcus lactis/genética , Lactococcus lactis/metabolismo , Lactococcus lactis/imunologia , Ligante RANK/imunologia , Ligante RANK/genética , Ligante RANK/metabolismo , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/genética , Proteínas Recombinantes/administração & dosagem , Infecções por Birnaviridae/prevenção & controle , Infecções por Birnaviridae/imunologia , Infecções por Birnaviridae/veterinária , Doenças das Aves Domésticas/prevenção & controle , Doenças das Aves Domésticas/imunologia , Doenças das Aves Domésticas/microbiologia , Vírus da Doença Infecciosa da Bursa/imunologia , Vírus da Doença Infecciosa da Bursa/genética , Diferenciação Celular , Nódulos Linfáticos Agregados/imunologia

RESUMO

The gastrointestinal (GI) tract and the brain form bidirectional nervous, immune, and endocrine communications known as the gut-brain axis. Several factors can affect this axis; among them, various studies have focused on the microbiota and imply that alterations in microbiota combinations can influence both the brain and GI. Also, many studies have shown that the immune system has a vital role in varying gut microbiota combinations. In the current paper, we will review the multidirectional effects of gut microbiota, immune system, and nervous system on each other. Specifically, this review mainly focuses on the impact of Peyer's patches as a critical component of the gut immune system on the gut-brain axis through affecting the gut's microbial composition. In this way, some factors were discussed as proposed elements of missing gaps in this field.

Assuntos

Eixo Encéfalo-Intestino , Microbioma Gastrointestinal , Nódulos Linfáticos Agregados , Nódulos Linfáticos Agregados/imunologia , Humanos , Microbioma Gastrointestinal/imunologia , Microbioma Gastrointestinal/fisiologia , Animais , Eixo Encéfalo-Intestino/fisiologia , Eixo Encéfalo-Intestino/imunologia , Encéfalo/imunologia , Encéfalo/fisiologia , Trato Gastrointestinal/microbiologia , Trato Gastrointestinal/imunologia

RESUMO

Recently, the intestinal lymphatic transport based on Peyer's patches (PPs) is emerging as a promising absorption pathway for natural polysaccharides. Herein, the aim of this study is to investigate the PP-based oral absorption of a pectic polysaccharide from Smilax china L. (SCLP), as well as its uptake and transport mechanisms in related immune cells. Taking advantages of the traceability of fluorescently labeled SCLP, we confirmed that SCLP could be absorbed into PPs and captured by their mononuclear phagocytes (dendritic cells and macrophages) following oral administration. Subsequently, the systematic in vitro study suggested that the endocytic mechanisms of SCLP by model mononuclear phagocytes (BMDCs and RAW264.7 cells) mainly involved caveolae-mediated endocytosis, macropinocytosis and phagocytosis. More importantly, SCLP directly binds and interacts with toll-like receptor 2 (TLR2) and galectin 3 (Gal-3) receptor, and was taken up by mononuclear phagocytes in receptor-mediated manner. After internalization, SCLP was intracellularly transported primarily through endolysosomal pathway and ultimately localized in lysosomes. In summary, this work reveals novel information and perspectives about the in vivo fate of SCLP, which will contribute to further research and utilization of SCLP and other pectic polysaccharides.

Assuntos

Nódulos Linfáticos Agregados , Smilax , Animais , Camundongos , Células RAW 264.7 , Nódulos Linfáticos Agregados/metabolismo , Smilax/química , Endocitose , Pectinas/química , Pectinas/metabolismo , Macrófagos/metabolismo , Macrófagos/efeitos dos fármacos , Fagocitose/efeitos dos fármacos , Fagócitos/metabolismo , Fagócitos/efeitos dos fármacos , Receptor 2 Toll-Like/metabolismo , Camundongos Endogâmicos BALB C , Masculino , Células Dendríticas/metabolismo , Células Dendríticas/efeitos dos fármacos , Administração Oral

RESUMO

Introduction: Cryptosporidiosis is a poorly controlled zoonosis caused by an intestinal parasite, Cryptosporidium parvum, with a high prevalence in livestock (cattle, sheep, and goats). Young animals are particularly susceptible to this infection due to the immaturity of their intestinal immune system. In a neonatal mouse model, we previously demonstrated the importance of the innate immunity and particularly of type 1 conventional dendritic cells (cDC1) among mononuclear phagocytes (MPs) in controlling the acute phase of C. parvum infection. These immune populations are well described in mice and humans, but their fine characterization in the intestine of young ruminants remained to be further explored. Methods: Immune cells of the small intestinal Peyer's patches and of the distal jejunum were isolated from naive lambs and calves at different ages. This was followed by their fine characterization by flow cytometry and transcriptomic analyses (q-RT-PCR and single cell RNAseq (lamb cells)). Newborn animals were infected with C. parvum, clinical signs and parasite burden were quantified, and isolated MP cells were characterized by flow cytometry in comparison with age matched control animals. Results: Here, we identified one population of macrophages and three subsets of cDC (cDC1, cDC2, and a minor cDC subset with migratory properties) in the intestine of lamb and calf by phenotypic and targeted gene expression analyses. Unsupervised single-cell transcriptomic analysis confirmed the identification of these four intestinal MP subpopulations in lamb, while highlighting a deeper diversity of cell subsets among monocytic and dendritic cells. We demonstrated a weak proportion of cDC1 in the intestine of highly susceptible newborn lambs together with an increase of these cells within the first days of life and in response to the infection. Discussion: Considering cDC1 importance for efficient parasite control in the mouse model, one may speculate that the cDC1/cDC2 ratio plays also a key role for the efficient control of C. parvum in young ruminants. In this study, we established the first fine characterization of intestinal MP subsets in young lambs and calves providing new insights for comparative immunology of the intestinal MP system across species and for future investigations on host-Cryptosporidium interactions in target species.

Assuntos

Criptosporidiose , Cryptosporidium parvum , Homeostase , Animais , Criptosporidiose/imunologia , Criptosporidiose/parasitologia , Cryptosporidium parvum/imunologia , Ovinos , Bovinos , Homeostase/imunologia , Células Dendríticas/imunologia , Células Dendríticas/parasitologia , Fagócitos/imunologia , Fagócitos/parasitologia , Animais Recém-Nascidos , Doenças dos Ovinos/parasitologia , Doenças dos Ovinos/imunologia , Nódulos Linfáticos Agregados/imunologia , Nódulos Linfáticos Agregados/parasitologia , Macrófagos/imunologia , Macrófagos/parasitologia , Intestinos/parasitologia , Intestinos/imunologia , Ruminantes/parasitologia , Ruminantes/imunologia

RESUMO

CD200 is an anti-inflammatory protein that facilitates signal transduction through its receptor, CD200R, in cells, resulting in immune response suppression. This includes reducing M1-like macrophages, enhancing M2-like macrophages, inhibiting NK cell cytotoxicity, and downregulating CTL responses. Activation of CD200R has been found to modulate dendritic cells, leading to the induction or enhancement of Treg cells expressing Foxp3. However, the precise mechanisms behind this process are still unclear. Our previous study demonstrated that B cells in Peyer's patches can induce Treg cells, so-called Treg-of-B (P) cells, through STAT6 phosphorylation. This study aimed to investigate the role of CD200 in Treg-of-B (P) cell generation. To clarify the mechanisms, we used wild-type, STAT6 deficient, and IL-24 deficient T cells to generate Treg-of-B (P) cells, and antagonist antibodies (anti-CD200 and anti-IL-20RB), an agonist anti-CD200R antibody, CD39 inhibitors (ARL67156 and POM-1), a STAT6 inhibitor (AS1517499), and soluble IL-20RB were also applied. Our findings revealed that Peyer's patch B cells expressed CD200 to activate the CD200R on T cells and initiate the process of Treg-of-B (P) cells generation. CD200 and CD200R interaction triggers the phosphorylation of STAT6, which regulated the expression of CD200R, CD39, and IL-24 in T cells. CD39 regulated the expression of IL-24, which sustained the expression of CD223 and IL-10 and maintained the cell viability. In summary, the generation of Treg-of-B (P) cells by Peyer's patch B cells was through the CD200R-STAT6-CD39-IL-24 axis pathway.

Assuntos

Linfócitos B , Fator de Transcrição STAT6 , Linfócitos T Reguladores , Animais , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismo , Camundongos , Linfócitos B/imunologia , Linfócitos B/metabolismo , Fator de Transcrição STAT6/metabolismo , Camundongos Endogâmicos C57BL , Receptores de Orexina/metabolismo , Receptores de Orexina/genética , Antígenos CD/metabolismo , Antígenos CD/genética , Antígenos CD/imunologia , Transdução de Sinais , Fosforilação , Nódulos Linfáticos Agregados/imunologia , Nódulos Linfáticos Agregados/metabolismo , Nódulos Linfáticos Agregados/citologia , Apirase/metabolismo , Apirase/imunologia , Glicoproteínas de Membrana

RESUMO

Nefecon, a targeted-release capsule formulation of budesonide approved for the reduction of proteinuria in adults with primary immunoglobulin A nephropathy, targets overproduction of galactose-deficient immunoglobulin A type 1 in the Peyer's patches at the gut mucosal level. To investigate whether the commercial formulation of Nefecon capsules reliably releases budesonide to the distal ileum, a human study was conducted with test capsules reproducing the delayed-release function of Nefecon capsules. Caffeine was included in the test capsules as a marker for capsule opening in the gut since it appears rapidly in saliva after release from orally administered dosage forms. Magnetic resonance imaging with black iron oxide was used to determine the capsule's position in the gut at the time caffeine was first measured in saliva and additionally to directly visualize dispersion of the capsule contents in the gut. In vitro dissolution results confirmed that the test capsules had the same delayed-release characteristics as Nefecon capsules. In 10 of 12 human volunteers, the capsule was demonstrated to open in the distal ileum; in the other two subjects, it opened just past the ileocecal junction. These results compared favorably with the high degree of variability seen in other published imaging studies of delayed-release formulations targeting the gut. The test capsules were shown to reliably deliver their contents to the distal ileum, the region with the highest concentration of Peyer's patches.

Assuntos

Budesonida , Cápsulas , Sistemas de Liberação de Medicamentos , Íleo , Humanos , Íleo/metabolismo , Íleo/efeitos dos fármacos , Adulto , Sistemas de Liberação de Medicamentos/métodos , Masculino , Budesonida/administração & dosagem , Budesonida/farmacocinética , Budesonida/química , Feminino , Cápsulas/química , Preparações de Ação Retardada/administração & dosagem , Preparações de Ação Retardada/farmacocinética , Imageamento por Ressonância Magnética/métodos , Administração Oral , Pessoa de Meia-Idade , Cafeína/química , Cafeína/administração & dosagem , Nódulos Linfáticos Agregados/metabolismo , Nódulos Linfáticos Agregados/efeitos dos fármacos , Adulto Jovem

RESUMO

Induction of commensal-specific immunity contributes to tissue homeostasis, yet the mechanisms underlying induction of commensal-specific B cells remain poorly understood in part due to a lack of tools to identify these cells. Using phage display, we identified segmented filamentous bacteria (SFB) antigens targeted by serum and intestinal antibodies and generated B cell tetramers to track SFB-specific B cells in gut-associated lymphoid tissues. We revealed a compartmentalized response in SFB-specific B cell activation, with a gradient of immunoglobulin A (IgA), IgG1, and IgG2b isotype production along Peyer's patches contrasted by selective production of IgG2b within mesenteric lymph nodes. V(D)J sequencing and monoclonal antibody generation identified somatic hypermutation driven affinity maturation to SFB antigens under homeostatic conditions. Combining phage display and B cell tetramers will enable investigation of the ontogeny and function of commensal-specific B cell responses in tissue immunity, inflammation, and repair.

Assuntos

Linfócitos B , Animais , Linfócitos B/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Nódulos Linfáticos Agregados/imunologia , Ativação Linfocitária/imunologia , Antígenos de Bactérias/imunologia , Hipermutação Somática de Imunoglobulina , Biblioteca de Peptídeos , Linfonodos/imunologia , Técnicas de Visualização da Superfície Celular , Simbiose/imunologia , Imunoglobulina G/imunologia , Imunoglobulina A/imunologia

RESUMO

Vedolizumab (VDZ) is a first-line treatment in ulcerative colitis (UC) that targets the α4ß7- mucosal vascular addressin cell adhesion molecule 1 (MAdCAM-1) axis. To determine the mechanisms of action of VDZ, we examined five distinct cohorts of patients with UC. A decrease in naïve B and T cells in the intestines and gut-homing (ß7+) plasmablasts in circulation of VDZ-treated patients suggested that VDZ targets gut-associated lymphoid tissue (GALT). Anti-α4ß7 blockade in wild-type and photoconvertible (KikGR) mice confirmed a loss of GALT size and cellularity because of impaired cellular entry. In VDZ-treated patients with UC, treatment responders demonstrated reduced intestinal lymphoid aggregate size and follicle organization and a reduction of ß7+IgG+ plasmablasts in circulation, as well as IgG+ plasma cells and FcγR-dependent signaling in the intestine. GALT targeting represents a previously unappreciated mechanism of action of α4ß7-targeted therapies, with major implications for this therapeutic paradigm in UC.

Assuntos

Colite Ulcerativa , Humanos , Animais , Camundongos , Colite Ulcerativa/tratamento farmacológico , Integrinas , Mucosa Intestinal , Nódulos Linfáticos Agregados , Imunoglobulina G/uso terapêutico

RESUMO

The development of psoriasis is mainly driven by the dysregulation of T cells within the skin, marking a primary involvement of these cells in the pathogenesis. Although B cells are integral components of the immune system, their role in the initiation and progression of psoriasis is not as pivotal as that of T cells. The paradox of B cell suggests that, while it is crucial for adaptive immunity, B cells may contribute to the exacerbation of psoriasis. Numerous ideas proposed that there are potential relationships between psoriasis and B cells especially within germinal centers (GCs). Recent research projected that B cells might be triggered by autoantigens which then induced molecular mimicry to alter B cells activity within GC and generate autoantibodies and pro-inflammatory cytokines, form ectopic GC, and dysregulate the proliferation of keratinocytes. Hence, in this review, we gathered potential evidence indicating the participation of B cells in psoriasis within the context of GC, aiming to enhance our comprehension and advance treatment strategies for psoriasis thus inviting many new researchers to investigate this issue.

Assuntos

Linfócitos B , Centro Germinativo , Psoríase , Animais , Humanos , Linfócitos B/imunologia , Citocinas/metabolismo , Citocinas/imunologia , Centro Germinativo/imunologia , Queratinócitos/imunologia , Psoríase/imunologia , Psoríase/patologia , Pele/imunologia , Pele/patologia , Linfócitos T/imunologia , Nódulos Linfáticos Agregados/imunologia

RESUMO

Induction and regulation of specific intestinal immunoglobulin (Ig)A responses critically depend on dendritic cell (DC) subsets and the T cells they activate in the Peyer's patches (PP). We found that oral immunization with cholera toxin (CT) as an adjuvant resulted in migration-dependent changes in the composition and localization of PP DC subsets with increased numbers of cluster of differentiation (CD)103- conventional DC (cDC)2s and lysozyme-expressing DC (LysoDCs) in the subepithelial dome and of CD103+ cDC2s that expressed CD101 in the T cell zones, while oral ovalbumin (OVA) tolerization was instead associated with greater accumulation of cDC1s and peripherally induced regulatory T cells (pTregs) in this area. Decreased IgA responses were observed after CT-adjuvanted immunization in huCD207DTA mice lacking CD103+ cDC2s, while oral OVA tolerization was inefficient in cDC1-deficient Batf3-/- mice. Using OVA transgenic T cell receptor CD4 T cell adoptive transfer models, we found that co-transferred endogenous wildtype CD4 T cells can hinder the induction of OVA-specific IgA responses through secretion of interleukin-10. CT could overcome this blocking effect, apparently through a modulating effect on pTregs while promoting an expansion of follicular helper T cells. The data support a model where cDC1-induced pTreg normally suppresses PP responses for any given antigen and where CT's oral adjuvanticity effect is dependent on promoting follicular helper T cell responses through induction of CD103+ cDC2s.

Assuntos

Antígenos CD , Antígeno CD11b , Movimento Celular , Toxina da Cólera , Células Dendríticas , Tolerância Imunológica , Imunização , Imunoglobulina A , Cadeias alfa de Integrinas , Camundongos Knockout , Ovalbumina , Nódulos Linfáticos Agregados , Linfócitos T Reguladores , Animais , Camundongos , Nódulos Linfáticos Agregados/imunologia , Nódulos Linfáticos Agregados/metabolismo , Cadeias alfa de Integrinas/metabolismo , Antígenos CD/metabolismo , Células Dendríticas/imunologia , Imunoglobulina A/imunologia , Imunoglobulina A/metabolismo , Administração Oral , Toxina da Cólera/imunologia , Ovalbumina/imunologia , Ovalbumina/administração & dosagem , Linfócitos T Reguladores/imunologia , Antígeno CD11b/metabolismo , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Fatores de Transcrição de Zíper de Leucina Básica/genética , Camundongos Transgênicos , Camundongos Endogâmicos C57BL , Transferência Adotiva , Proteínas Repressoras

RESUMO

Peyer's patches (PPs) are lymphoid structures situated adjacent to the intestinal epithelium that support B cell responses that give rise to many intestinal IgA-secreting cells. Induction of isotype switching to IgA in PPs requires interactions between B cells and TGFß-activating conventional dendritic cells type 2 (cDC2s) in the subepithelial dome (SED). However, the mechanisms promoting cDC2 positioning in the SED are unclear. Here, we found that PP cDC2s express GPR35, a receptor that promotes cell migration in response to various metabolites, including 5-hydroxyindoleacetic acid (5-HIAA). In mice lacking GPR35, fewer cDC2s were found in the SED, and frequencies of IgA+ germinal center (GC) B cells were reduced. IgA plasma cells were reduced in both the PPs and lamina propria. These phenotypes were also observed in chimeric mice that lacked GPR35 selectively in cDCs. GPR35 deficiency led to reduced coating of commensal bacteria with IgA and reduced IgA responses to cholera toxin. Mast cells were present in the SED, and mast cell-deficient mice had reduced PP cDC2s and IgA+ cells. Ablation of tryptophan hydroxylase 1 (Tph1) in mast cells to prevent their production of 5-HIAA similarly led to reduced PP cDC2s and IgA responses. Thus, mast cell-guided positioning of GPR35+ cDC2s in the PP SED supports induction of intestinal IgA responses.

Assuntos

Linfócitos B , Mastócitos , Animais , Camundongos , Ácido Hidroxi-Indolacético , Movimento Celular , Imunoglobulina A Secretora , Nódulos Linfáticos Agregados , Receptores Acoplados a Proteínas G/genética