Secretory IgA's complex roles in immunity and mucosal homeostasis in the gut

Gut microbiota metabolites, secretory immunoglobulin A and Bayley-III cognitive scores in children from the CHILD Cohort Study

Background

Dysbiosis of the gut microbiota has been demonstrated in neurodevelopmental disorders but the underlying mechanisms that may explain these associations are poorly understood. Gut secretory immunoglobulin A (SIgA) binds pathogenic microbes, preventing mucosal penetration. Gut microbes also influence SIgA production and its binding characteristics through short-chain fatty acid (SCFA) metabolites, allowing them to regulate the immune response. Serum IgA deficiency has been noted in children with autism spectrum disorders (ASD). In this study, we aimed to determine whether SIgA level in infancy is associated with gut microbiota taxonomy and metabolites, and neurodevelopmental outcomes in preschool children.

Methods

For a subsample of 178 children from the Canadian CHILD Cohort Study, gut microbiota of fecal samples collected at 3-4 months and 12 months was profiled using 16S rRNA sequencing. Gut bacterial metabolites levels and SIgA level were measured by nuclear magnetic resonance (NMR) based metabolomics and SIgA enzyme-linked immunosorbent assay at 3-4 months, respectively. Bayley-III Scale of Infant Development was assessed at 12 and 24 months. We evaluated direct relationships in multiple linear regression models and putative causal relationships in statistical mediation models.

Results

Propionate and butyrate levels at 3-4 months were associated with decreased Bayley cognitive score at 24 months (p-values: 0.01 and 0.02, respectively) in adjusted multiple linear regression models, but when we investigated an indirect relationship mediated by decreased SIgA level at 3-4 months, it did not reach statistical significance (p-values: 0.18 and 0.20, respectively). Lactate level at 3-4 months was associated with increased Bayley cognitive score at 24 months in adjusted multiple linear regression models (p-value: 0.01), but the statistical model mediated by increased SIgA level at 3-4 months did not reach statistical significance neither (p-value: 0.20).

Conclusions

Our study contributes to growing evidence that neurodevelopment is influenced by the infant gut microbiota and that it might involve SIgA level, but larger studies are required.

Klebsiella pneumoniae Glycoconjugate Vaccine Leads Based on Semi-Synthetic O1 and O2ac Antigens

Klebsiella pneumoniae (KP) is a common opportunistic pathogen that emerged as a new critical threat to human health, due to its hypervirulence and widespread resistance against many antibiotics, including carbapenems. Alternative intervention strategies such as vaccines are not available. Cell-surface lipopolysaccharides (LPS) and capsular polysaccharides (CPS) are attractive targets for vaccine development. We present a method to synthesize LPS substructures, covering over 70 % of virulent KP strains that were used to characterize the antibody repertoire of infected patients. Thereby, glycoconjugate vaccine leads against the Klebsiella pneumoniae serotypes O1, O2a, O2afg and O2ac have been identified.

Changes of diamine oxidase and D-lactate in human breast and gynecologic cancers after chemotherapy

This study investigates the changes in diamine oxidase (DAO) and D-lactate levels in cancer patients undergoing chemotherapy and their clinical significance in evaluating intestinal barrier function. Breast and gynecologic cancer patients who received chemotherapy between January 2020 and December 2023 were enrolled from our hospital. Blood samples were taken before chemotherapy, within 3 days after chemotherapy, and before the next course of chemotherapy. The level of plasma DAO and D-lactate were measured by enzyme-linked immunosorbent assay (ELISA). After chemotherapy, nutritional markers such as albumin (ALB) and prealbumin (PAB) were evaluated. Anorexia, vomiting, nausea and diarrhea were evaluated during the chemotherapy cycle. There were no notable differences in serum DAO and D-lactate levels before chemotherapy among different tumor types, tumor stage and chemotherapy type. Serum DAO and D-lactate levels after chemotherapy were significantly elevated compared to their levels before chemotherapy (P < .05). The plasma DAO and D-lactate levels in cancer patients before the next course of chemotherapy were higher than those observed before the initial treatment, but the difference failed to achieve statistical significance (P > .05). The levels of DAO before chemotherapy were higher in patients with diarrhea and anorexia after chemotherapy than those without diarrhea and anorexia (P < .05). The levels of D-lactate before chemotherapy were notably elevated in patients with vomiting, diarrhea and nausea after chemotherapy than those without vomiting, diarrhea and nausea (P < .05). Monitoring serum levels of DAO and D-lactate in cancer patients undergoing chemotherapy can serve as indicators for evaluating gastrointestinal dysfunction and nutritional status.

Burning Mouth Syndrome May Essentially Be Related To Psychoneuroimmunology: Mechanism Hypothesis

BACKGROUND

Burning mouth syndrome (BMS) is a chronic intraoral dysesthesia with elusive aetiology, only few studies have been carried out on immune function in BMS patients. We aimed to investigate the role immune function paly in the pathogenesis of BMS by psychoneuroimmunology (PNI).

METHOD

We recruited 44 BMS patients and 31 controls. We measured the anxiety and depression levels by the Zung' Self-rating Anxiety Scale (SAS) and Zung' Self-rating Depression Scale (SDS), respectively. Serological immunity included cellular immunity, humoral immunity and autoantibody. Visual analogue scale (VAS) was used to quantify pain levels. We used the Pearson correlation analysis to analyse the relationship between pain, psychology and immune function.

RESULTS

BMS exhibited higher levels of anxiety and depression (***p < 0.001 for both). In BMS, the CD3+ cells, CD4+ cells were lower (*p = 0.028, 0.046 and 0.033, respectively), IgE and antinuclear antibody (ANA) was higher (*p = 0.035). The average VAS score among BMS was approximately 3.7. Pearson correlation analysis revealed positive correlations between VAS, SAS and SDS; negative correlations between these scores of VAS, SAS, SDS and the levels of CD3+ cells, CD4+ cells, CD8+ cells.

CONCLUSIONS

BMS were more painful, anxious, depressive, and immunity dysfunction than controls. We proposed a mechanism hypothesis that the BMS may essentially be an immunological disease.

The Geometric Framework for Nutrition and Its Application to Rodent Models

Rodents have been the primary model for mammalian nutritional physiology for decades. Despite an extensive body of literature, controversies remain around the effects of specific nutrients and total energy intake on several aspects of nutritional biology, even in this well-studied model. One approach that is helping to bring clarity to the field is the geometric framework for nutrition (GFN). The GFN is a multidimensional paradigm that can be used to conceptualize nutrition and nutritional effects, design experiments, and interpret results. To date, more than 30 publications have applied the GFN to data from rodent models of nutrition. Here we review the major conclusions from these studies. We pay particular attention to the effects of macronutrients on satiety, glucose metabolism, lifespan and the biology of aging, reproductive function, immune function, and the microbiome. We finish by highlighting several knowledge gaps that became evident upon reviewing this literature.

Modulation of Intestinal Flora: a Novel Immunotherapeutic Approach for Enhancing Thyroid Cancer Treatment

Over the past 3 years, there has been a growing interest in clinical research regarding the potential involvement of intestinal flora in thyroid cancer (TC). This review delves into the intricate connection between intestinal flora and TC, focusing on the particular intestinal flora that is directly linked to the disease and identifying which may be able to predict potential microbial markers of TC. In order to shed light on the inflammatory pathways connected to the onset of TC, we investigated the impact of intestinal flora on immune modulation and the connection between chronic inflammation when investigating the role of intestinal flora in the pathogenesis of TC. Furthermore, the potential role of intestinal flora metabolites in the regulation of thyroid function was clarified by exploring the effects of short-chain fatty acids and lipopolysaccharide on thyroid hormone synthesis and metabolism. Based on these findings, we further explore the effects of probiotics, prebiotics, postbiotics, vitamins, and trace elements.

Gardnerella vaginalis-binding IgA in the urethra of sexually experienced males

BACKGROUND

Genital inflammation increases HIV susceptibility and is associated with the density of pro-inflammatory anaerobes in the vagina and coronal sulcus. The penile urethra is a critical site of HIV acquisition, although correlates of urethral HIV acquisition are largely unknown. While Streptococcus mitis is a consistent component of the urethral flora, the presence of Gardnerella vaginalis has been linked with prior penile-vaginal sex and urethral inflammation. Here, we use a flow cytometry-based bacterial assay to quantify urethral IgA and IgG that bind G. vaginalis and S. mitis in a cross-sectional cohort of 45 uncircumcised Ugandan men and to evaluate their association with the urethral microbiome and local soluble immune factors.

RESULTS

Urethral antibodies binding both bacterial species were readily detectable, with G. vaginalis predominantly bound by IgA, and S. mitis equivalently by IgA and IgG. Gardnerella vaginalis-binding IgA was elevated in participants with detectable urethral Gardnerella, with the latter only present in participants who reported prior penile-vaginal sex. In contrast, detectable urethral S. mitis was not associated with sexual history or levels of S. mitis-binding IgA/IgG. The time from the last penile-vaginal sex was inversely correlated with the urethral concentrations of total IgA, G. vaginalis-binding IgA, and chemokines IL-8 and MIP-1β; these inflammatory chemokines were independently associated with higher total IgA concentration, but not with G. vaginalis-binding IgA.

CONCLUSIONS

This first description of microbe-binding antibodies in the penile urethra suggests that urethral colonization by Gardnerella after penile-vaginal sex specifically induces a G. vaginalis-binding IgA response. Prospective studies of the host-microbe relationship in the urethra may have implications for the development of vaccines against sexually-transmitted bacteria. Video Abstract.

Antibodies and Inflammation: Fecal Biomarkers of Gut Health in Domestic Ruminants

Gastrointestinal infections present major challenges to ruminant livestock systems, and gut health is a key constraint on fitness, welfare, and productivity. Fecal biomarkers present opportunities to monitor animal health without using invasive methods, and with greater resolution compared to observational metrics. Here we developed enzyme-linked immunosorbent assays for three potential fecal biomarkers of gut health in domestic ruminants: two immunological (total immunoglobulin [Ig]A and total IgG) and one inflammatory (lactoferrin). We analytically validated the assays, then evaluated whether they could be used as a biomarker of clinically diagnosed gastrointestinal pathologies in cattle (Bos taurus), and finally compared them with helminth fecal egg counts in sheep (Ovis aries). The analytes were detected above the lower limits of detection in cattle, sheep, and goats. Fecal IgA and lactoferrin were higher in cattle with infectious pathologies (strongyles, coccidiosis and symptomatic Johne's disease) compared to healthy controls. Lactoferrin was additionally higher in animals with infectious pathologies compared to noninfectious pathologies, and to asymptomatic Johne's cases. No significant relationships were found with sheep fecal egg counts. These initial findings suggest that fecal IgA and lactoferrin may be useful biomarkers of poor gastrointestinal health in cattle, and that fecal lactoferrin is specific to active inflammation caused by infectious agents. These could be incorporated into the growing suite of noninvasive ecoimmunological tools and used to understand ruminant gut health in a range of species. Applications include improving treatment regimens for gastrointestinal infections, and understanding wildlife physiological responses to infectious challenges.

Effect of high-fat diet on IgA+ cells and BAFF/APRIL in small intestinal villous lamina propria of mice

Obesity exacerbates susceptibility to infectious diseases. We investigated the effects of a high-fat diet (HFD) on intestinal immunity, particularly immunoglobulin (Ig)A-producing cells, B-cell activating factor (BAFF), and a proliferation-inducing ligand (APRIL) localization. Mice (4- to 20-weeks old) were fed HFD or standard chow diet, and their jejunum and ileum were fixed using the in vivo cryotechnique. Immunohistochemistry was performed for IgA, BAFF, and APRIL. In the HFD group, IgA+, IgA+CD22+ (p < 0.001), and IgA+CD138- (p = 0.007) cell counts were diminished in the middle sections of the lamina propria of jejunal villi, and BAFF levels were significantly reduced in jejunal villi. The HFD effects on IgA+ cell distribution seem to be confined to jejunal villi, hinting at localized vulnerabilities in intestinal immunity during obesity. Moreover, in the HFD group, IgA+ B-cell counts were reduced in the middle jejunum, indicating inhibition of the IgA+ B-cells through a T-cell-independent pathway.

Malnutrition and Its Influence on Gut sIgA-Microbiota Dynamics

In the current era, malnutrition is seen as both undernutrition and overweight and obesity; both conditions are caused by nutrient deficiency or excess and improper use or imbalance in the intake of macro and micronutrients. Recent evidence suggests that malnutrition alters the intestinal microbiota, known as dysbiosis. Secretory immunoglobulin A (sIgA) plays an important role in maintaining and increasing beneficial intestinal microbiota populations and protecting against pathogenic species. Depletion of beneficial bacterial populations throughout life is also conditioned by malnutrition. This review aims to synthesize the evidence that establishes an interrelationship between diet, malnutrition, changes in the intestinal flora, and sIgA levels. Targeted nutritional therapies combined with prebiotic, probiotic, and postbiotic administration can restore the immune response in the intestine and the host's homeostasis.

Mucosal immune response in biology, disease prevention and treatment

The mucosal immune system, as the most extensive peripheral immune network, serves as the frontline defense against a myriad of microbial and dietary antigens. It is crucial in preventing pathogen invasion and establishing immune tolerance. A comprehensive understanding of mucosal immunity is essential for developing treatments that can effectively target diseases at their entry points, thereby minimizing the overall impact on the body. Despite its importance, our knowledge of mucosal immunity remains incomplete, necessitating further research. The outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has underscored the critical role of mucosal immunity in disease prevention and treatment. This systematic review focuses on the dynamic interactions between mucosa-associated lymphoid structures and related diseases. We delve into the basic structures and functions of these lymphoid tissues during disease processes and explore the intricate regulatory networks and mechanisms involved. Additionally, we summarize novel therapies and clinical research advances in the prevention of mucosal immunity-related diseases. The review also addresses the challenges in developing mucosal vaccines, which aim to induce specific immune responses while maintaining tolerance to non-pathogenic microbes. Innovative therapies, such as nanoparticle vaccines and inhalable antibodies, show promise in enhancing mucosal immunity and offer potential for improved disease prevention and treatment.

Effects of Chenpi (Citrus reticulata cv. Chachiensis) on serum antioxidant enzymes, inflammatory factors, and intestinal health in Beagle dogs

Ensuring companion animal welfare is a top priority for the pet industry and owners alike. The health of the pets can be directly and effectively improved through diet. Chenpi includes beneficial ingredients with proven anti-inflammatory, antioxidant, and immunomodulatory properties. The present investigation involved feeding snacks infused with Chenpi powder (CPP) to dogs for 42 days to examine the potential health benefits of CPP. The research evidenced a notable increase in serum superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activity in dogs, accompanied by a decrease in malondialdehyde (MDA), interleukin-8 (IL-8), and interferon-gamma (IFN-γ) level. Additionally, CPP increased fecal scores and significantly reduced fecal odors due to inhibition of 3-methylindole, hydrogen sulfide (H2S), and ammonia nitrogen (NH4 +-N), and also raised the levels of fecal secretory immunoglobulin A (SIgA). Analysis of the microbial composition via 16S rRNA sequencing showed that CPP increased Bacteroidota and decreased Firmicutes in the gut flora at the phylum level. Functional prediction study of microbial communities also showed that the CPP group enriched metabolic and genetic information processing pathways. In addition, there were significant correlations between serum indicators and several significantly altered microorganisms. These findings suggest that CPP can potentially enhance the overall health of dogs by reducing fecal odorants, enhancing antioxidant and immunological capabilities, and modulating intestinal flora. This study establishes a solid scientific foundation regarding the application of CPP in functional pet foods.

Enteromorpha prolifera polysaccharide-Fe (III) complex promotes intestinal development as a new iron supplement

Iron is a crucial micronutrient, and its deficiency can have detrimental effects on the health of infants. Dietary polysaccharide-iron (III) complexes (PICs) are promising for addressing iron deficiency due to their minimal adverse reactions and high iron absorption rate. This study aimed to investigate the effects of dietary Enteromorpha prolifera polysaccharide-Fe (III) complex (EP-Fe) on newborns, using 3-day weaned piglets as the iron-deficiency model. Results showed that EP-Fe improved iron levels and promoted intestinal development in piglets. Transcriptome sequencing revealed that EP-Fe increased the survival of intestinal epithelial cells under hypoxia by upregulating the expression of genes that promote the development of the vascular system. Additionally, EP-Fe enhanced the mucosal barrier functions by inhibiting myosin light chain kinase (MLCK)/phosphorylated myosin light chain (p-MLC) signaling pathway to increase the expression of intestinal tight junction proteins. Furthermore, the 16S rRNA gene sequencing of gut microbiota showed that EP-Fe promoted the enrichment of Bacteroides_fragilis and other gut microbes that can metabolize carbohydrates. In conclusion, EP-Fe is an effective iron supplement for newborns, and it can be developed as a comprehensive nutritional supplement.

Roles of Probiotics, Prebiotics, and Postbiotics in B-Cell-Mediated Immune Regulation

Probiotics, prebiotics, and postbiotics can significantly influence B-cell-related diseases through their immunomodulatory effects. They enhance the immune system's function, particularly affecting B cells, which originate in the bone marrow and are crucial for antibody production and immune memory. These substances have therapeutic potential in managing allergies, autoimmune diseases, and inflammatory conditions by regulating the gut microbiota, strengthening epithelial barriers, and directly interacting with various components of the innate and adaptive immune systems. The review highlights the critical need for further research into the precise mechanisms through which probiotics, prebiotics, and postbiotics modulate B cells. Gaining this understanding could facilitate the development of more effective treatments for B-cell-related diseases by harnessing the immunomodulatory properties of these dietary components.

Historical concepts and contemporary perspectives of dental caries-a tribute to Henrik Dam (1895-1976)

Dental caries is a multifactorial disease, which is the result of a complex interplay between the diet, the host, the saliva, and dental biofilms. Although the prevalence of dental caries has decreased dramatically since 1950 in many countries, it continues to be one of the most common health conditions globally. The aim of the present review is to summarize the investigations on dental caries performed by the late Noble prize winner Henrik Dam and his colleagues in the middle of the 20th century, and to relate the knowledge and state of the art at the time to current concepts on dental caries. Henrik Dam is mostly known for his discovery of Vitamin K, but he also conducted experimental studies on dental caries that focused on the role of Vitamin K, the diet, and saliva in the development of dental caries. The discoveries of Henrik Dam contributed to our understanding of the role of saliva and different dietary components, such as fat and proteins, in caries development and prevention.

Akkermansia muciniphila Promotes SIgA Production and Alters the Reactivity Toward Commensal Bacteria in Early-Weaned Piglets

BACKGROUND

Secretory IgA (SIgA) is the first line of defense in protecting the intestinal epithelium against pathogenic bacteria, regulating gut microbiota composition, and maintaining intestinal homeostasis. Early weaning strategies may disrupt SIgA levels in piglet intestines, causing a decline in immune response and early weaning stress. However, the specific microbial mechanisms modulating SIgA in early-weaned piglets are not well understood.

OBJECTIVES

We hypothesized that Akkermansia muciniphila increases intestinal SIgA production in the early-weaned piglets.

METHODS

Fecal SIgA levels, SIgA-coated bacteria abundance, and fecal metagenomes were compared between 6 Huanjiang miniature (HM) and 6 Duroc×Landrace×Yorkshire (DLY) early-weaned piglets to identify bacterial species involved in SIgA modulation. Four bacterial species were investigated using 5 groups (Control, A. muciniphila, L. amylovorus, L. crispatus, and L. acidophilus) of male specific pathogen-free C57BL/6J mice, weaned 3 wk postbirth (n = 8/group). Subsequently, 10-d-old Landrace×Yorkshire (LY) piglets were randomly assigned to 3 groups (Control, 109A. muciniphila, and 108A. muciniphila) (n = 10/group) to evaluate the effect of orally administered A. muciniphila on intestinal SIgA production and microbial composition.

RESULTS

HM early-weaned piglets showed significantly higher SIgA levels [7.59 μg/mg, 95% confidence interval (CI): 3.2, 12, P = 0.002] and SIgA-coated bacteria abundance (8.64%, 95% CI: 3.2, 14, P = 0.014) than DLY piglets. In the mouse model, the administration of A. muciniphila significantly increased SIgA levels (3.50 μg/mg, 95% CI: 0.59, 6.4, P = 0.018), SIgA-coated bacteria abundance (9.06%, 95% CI: 4, 14, P = 0.018), and IgA+ plasma cell counts (6.1%, 95% CI: 4.3, 8, P = 0.005). In the pig experiments, the oral administration of A. muciniphila to LY piglets significantly enhanced intestinal SIgA concentrations (4.22 μg/mg, 95% CI: 0.37, 8.5, P = 0.034) and altered the SIgA-coated bacterial landscape.

CONCLUSIONS

Early intervention with A. muciniphila in nursing piglets can increases intestinal SIgA production and alter the reactivity toward commensal bacteria upon early weaning.

CSF-1R blockade to alleviate azithromycin mediated immunosuppression in a mouse model of intracellular infection

Colony Stimulating Factor-1 Receptor (CSF-1R) signalling plays an important role in maturation, differentiation and activation of macrophages. Apposite generation and activation of macrophage phenotypes and subsequent adaptive immune response against any infection is decisive for a positive disease outcome. Antibiotic therapy is imperative for treating bacterial infections however antibiotics have off-target effects on host immune-cells. These effects could either be contextually beneficial or harmful and could potentially aid generation of infection persistence and antimicrobial resistance (AMR) via host immunosuppression. We had recently reported the immunosuppressive-mechanism of azithromycin-induced increased CSF-1R expression on murine-macrophages and bacterial-persistence in Balb/c model of intracellular infection. We further wanted to explore the molecular-mechanism behind these observations and tested GW2580-mediated CSF-1R blockade before azithromycin treatment during S. flexneri induced intracellular infection. In the presented study, we report that the azithromycin alters the protein expression or phosphorylation of transcription-factors ERK1/2, P38, AKT1, STAT3, STAT6, and EGR2 that are involved in macrophage polarisatoin and also take part in CSF-1R signalling pathways. Intrestingly, CSF-1R blockade using GW2580 abrogated or reversed the azithromycin-induced up- or down-regulated expression or phosphorylation of ERK1/2, P38, AKT1, STAT3, STAT6, and EGR2. We further validated our results in Balb/c model of S. flexneri infection. Intrestingly, the CSF-1R blocker and azithromycin treated mice showed batter recovery than the azithromycin alone treated mice and hence we report the aftermath of GW2580 with azithromycin treatment on disease and immunological outcome of an intracellular infection caused by Shigella flexneri.

The Role of Gut Microbiome in Irritable Bowel Syndrome: Implications for Clinical Therapeutics

Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder (FGID) characterized by chronic or recurrent gastrointestinal symptoms without organic changes, and it is also a common disorder of gut-brain interaction (DGBIs).. The symptoms of IBS not only affect the quality of life for individual patients but also place a significant burden on global healthcare systems. The lack of established and universally applicable biomarkers for IBS, along with the substantial variability in symptoms and progression, presents challenges in developing effective clinical treatments. In recent years, preclinical and clinical studies have linked the pathogenesis of IBS to alterations in the composition and function of the intestinal microbiota. Within the complex microbial community of the gut, intricate metabolic and spatial interactions occur among its members and between microbes and their hosts. Amid the multifaceted pathophysiology of IBS, the role of intestinal microenvironment factors in symptom development has become more apparent. This review aims to delve into the changes in the composition and structure of the gut microbiome in individuals with IBS. It explores how diet-mediated alterations in intestinal microbes and their byproducts play a role in regulating the pathogenesis of IBS by influencing the "brain-gut" axis, intestinal barrier function, immune responses, and more. By doing so, this review seeks to lay a theoretical foundation for advancing the development of clinical therapeutics for IBS.

The gut microbiome across the lifespan: how diet modulates our microbial ecosystem from infancy to the elderly

This comprehensive review examines the impact of dietary patterns on gut microbiome composition and diversity from infancy to old age, linking these changes to age-related health outcomes. It investigates how the gut microbiome develops and changes across life stages, focusing on the influence of dietary factors. The review explores how early-life feeding practices, including breastfeeding and formula feeding, shape the infant gut microbiota and have lasting effects. In elderly individuals, alterations in the gut microbiome are associated with increased susceptibility to infections, chronic inflammation, metabolic disorders and cognitive decline. The critical role of diet in modulating the gut microbiome throughout life is emphasised, particularly the potential benefits of probiotics and fortified foods in promoting healthy ageing. By elucidating the mechanisms connecting food systems to gut health, this review provides insights into interventions that could enhance gut microbiome resilience and improve health outcomes across the lifespan.

Nypa fruticans Wurmb Extract Recovered Compromised Immune Status Induced by Forced Swimming in a Mouse Model

Nypa fruticans Wurmb is known to contain large amounts of polyphenols and flavonoids with antioxidative and anti-inflammatory effects. However, the biological and physiological functions of N. fruticans have not been scientifically investigated. Thus, we investigated the immunomodulatory effect of N. fruticans hot water extract (YSK-N) in mice using an immune compromised model established by forced swimming (FS). Intensive exercise decreased body weight, organ index, and various immunological parameters in FS mice. However, oral administration of YSK-N significantly restored the FS-induced decreases in body, thymus, and spleen weights, as well as the reduction in the numbers of white blood cells and lymphocytes in the whole blood of mice. Additionally, YSK-N increased splenic cell proliferation in the absence and presence of concanavalin A or lipopolysaccharide stimulation in a concentration-dependent manner. Notably, YSK-N enhanced the cytotoxic activity of natural killer cells against YAC-1 tumor cells under immunosuppressive conditions. Furthermore, YSK-N supplementation reverted the FS-induced downregulation in immunoglobulin production and Il2, Il6, Il12, Ifnγ, Gzmb, and Prf1 mRNA expression. Therefore, our observations suggested that YSK-N promotes immune function and has potential as an immunomodulatory agent.

Phytobiotics in poultry: revolutionizing broiler chicken nutrition with plant-derived gut health enhancers

As the global population continues to expand, the demand for broiler chicken production to supply safe and high-quality meat is increasing. To meet this ever-growing demand, broiler chickens with enhanced growth performance are being developed, but they often face challenges related to oxidative stress, which can adversely affect gut health. Phytobiotics, which are plant-derived feed additives known for their antimicrobial, antioxidant, immune-modulating, and growth-promoting properties, have emerged as promising natural alternatives to synthetic antibiotics. This review consolidates recent advancements in the use of phytobiotics-derived products from leaves, roots, seeds, flowers, and their extracts in broiler diets reared under standard experimental conditions, without the introduction of stressors. The focus is on elucidating the key mechanisms through which phytobiotics improve gut health, including their effects on gut morphology, integrity, microflora composition, antioxidant capacity, and immune function. The review highlights the potential of phytobiotics to revolutionize broiler nutrition by acting as natural enhancers of gut health. Research findings reveal that phytobiotics significantly improve intestinal health, and boost growth performance, offering a sustainable approach to managing to gut dysfunction. These findings indicate a potential shift in how gut-health related challenges in broilers can be addressed, moving towards natural phytobiotic therapy. However, several challenges persist. Optimizing the dosage of phytobiotics, ensuring consistent performance, and overcoming the limitations related to their extraction and application are key areas requiring further investigation. The review emphasizes the importance of continued research to refine phytobiotic formulations, explore synergistic effects, and incorporate advanced technologies such as AI-driven methods and precision nutrition to tailor feeding strategies more effectively. Additionally, the development of innovative delivery systems, such as nanoencapsulation, is suggested as a way to enhance the effectiveness and reliability of phytobiotics. By highlighting the potential of phytobiotics to revolutionize broiler nutrition, this review supports the poultry industry's shift towards antibiotic-free and sustainable dietary solutions, offering new perspectives on the future of broiler chicken production.

The Gut-Lung Axis During Ethanol Exposure and a Pseudomonas aeruginosa Bacterial Challenge

Background: Susceptibility to and severity of pulmonary infections increase with ethanol consumption. We have previously shown that ethanol-induced changes in the gut microbiome disrupt gut homeostasis, allowing for the translocation of proinflammatory mediators into the circulation and eliciting an immune response in the lung. Additionally, targeting the gut with butyrate supplementation not only rescues ethanol-induced disruptions to gut health but also reverses aspects of immune dysregulation in the lungs. Here, we assessed the impact of this connection on a subsequent infectious challenge. Methods: To assess if ethanol-induced alterations to the gut microbiome could also impact the host response to a pulmonary infectious challenge, we employed a chronic-binge ethanol-feeding mouse model followed by a nasal instillation of Pseudomonas aeruginosa. Results: In addition to altering gut microbiome composition and metabolism, ethanol consumption also disrupted the local immune response as demonstrated by suppressed cecal SIgA levels, a decreased presence of CD3+CD8a+ cytotoxic T cells in the proximal colon mucosa, and depleted CD3+CD8a+ T cells and CD11c+CD8a+ dendritic cells in the mesenteric lymph nodes. Circulatory Ly6G+CD11b+ neutrophils increased, indicating a systemic change in immune-cell presence with ethanol exposure. Ethanol exposure increased CD11c+CD64+ macrophages and Ly6G+CD11b+ neutrophils in the lungs, with neutrophil populations being further exacerbated during a bacterial challenge with Pseudomonas aeruginosa. Lipocalin 2, a marker of oxidative stress, was also elevated with ethanol consumption, though not with infection. Conclusions: These data suggest that ethanol-induced changes in the gut microbiome and immune environment are linked to dysfunctional immune responses in the intestine, blood, and the lungs, compromising the pulmonary immune response during an infectious challenge in mice.

Screening optimal DC-targeting peptide to enhance the immune efficacy of recombinant Lactobacillus expressing RHDV VP60

Dendritic cells (DCs) present an ideal target for delivering immunogenic cargo due to their potent antigen-presenting capabilities. This targeting approach holds promise in vaccine development by enhancing the efficiency of antigen recognition and capture by DCs. To identify a high-affinity targeting peptide binding to rabbit DCs, rabbit monocyte-derived DCs (raMoDCs) were isolated and cultured, and a novel peptide, HS (HSLRHDYGYPGH), was identified using a phage-displayed peptide library. Alongside HS, two other DC-targeting peptides, KC1 and MY, previously validated in our laboratory, were employed to construct recombinant Lactgobacillus reuteri fusion-expressed rabbit hemorrhagic disease virus (RHDV) capsid protein VP60. These recombinant Lactobacillus strains were named HS-VP60/L. reuteri, KC1-VP60/L. reuteri, and MY-VP60/L. reuteri. The ability of these recombinant Lactobacillus to bind rabbit DCs was evaluated both in vivo and in vitro. Results demonstrated that the DC-targeting peptide KC1 significantly enhanced the capture efficiency of recombinant Lactobacillus by raMoDCs, promoted DC maturation, and increased cytokine secretion. Furthermore, oral administration of KC1-VP60/L. reuteri effectively induced SIgA and IgG production in rabbits, prolonged rabbit survival post-challenge, and reduced RHDV copies in organs. In summary, the DC-targeting peptide KC1 exhibited robust binding to raMoDCs, and recombinant Lactobacillus expressing KC1-VP60 protein antigens efficiently induced systemic and mucosal immune responses in rabbits, conferring protective efficacy against RHDV. This study offers valuable insights for the development of novel RHDV vaccines.

Effect of lipopolysaccharides from pathogenic bacteria on broiler chickens' productivity: a meta-analysis

1. This meta-analysis investigated the impact of LPS and covariates (serotype, rearing period and administration route) on the productivity parameters of broiler chickens (average daily feed intake (ADFI), average daily gain (ADG) and feed conversion ratio (FCR)).2. Thirty-two eligible studies were included. Hedges' g effect size was determined using a random-effects model at 95% confidence interval.3. Results showed that LPS significantly decreased average daily feed intake (ADFI; p < 0.0001) and average daily gain (ADG; p < 0.0001) and increased FCR (p < 0.0001). The serotypes Escherichia coli 055: B5 (EC055: B5) and Escherichia coli 0127: B8 (EC 0127: B8) significantly reduced ADFI and ADG, and the serotype EC 055: B5 significantly increased the FCR (p < 0.05).4. The intraperitoneal administration of the LPS significantly reduced the productivity of broiler chickens (p < 0.05), but other administration routes did not show such effects. The reduction in ADFI and ADG was found in all rearing periods (p < 0.05), and the increase in FCR was observed in the starter (p = 0.0302) and grower periods (p = 0.0031).5. Exposure to LPS significantly reduced the productivity of broiler chickens (p < 0.05). However, no relationship was observed between LPS dosage and productivity as indicated by the meta-regression study.6. The findings indicated that LPS has detrimental effects on broiler chickens' ADFI, ADG and FCR across various LPS serotypes and rearing periods. These detrimental impacts of LPS remain consistent regardless of the administered dosage.

Lacticaseibacillus rhamnosus LRa05 alleviates cyclophosphamide-induced immunosuppression and intestinal microbiota disorder in mice

Probiotics play a crucial role in regulating the gut microbiota and enhancing immune response. Oral administration of probiotics modulates intestinal microbiota composition and immune homeostasis. In this study, we investigated the immunoregulatory effect of Lacticaseibacillus rhamnosus LRa05 on cyclophosphamide (CTX)-induced immunosuppressive mice. The results showed that oral administration of LRa05 reduced weight loss, restored immune organ indices, and maintained the structural integrity of the intestinal tissue in CTX-treated mice. Moreover, oral administration of LRa05 exhibited immune-modulating properties by promoting the secretion of cytokines (tumor necrosis factor-α, interleukin-1β, interleukin-10, and secretory immunoglobulin A) in serum. Moreover, the analysis of 16S rRNA amplicon sequencing revealed that LRa05 increased gut microbiota diversity and regulated its composition. In detail, LRa05 intervention restored the Firmicutes/Bacteroidota ratio and significantly increased the relative abundance of Lachnospiraceae_NK4A136_group, Oscillibacter, Alloprevotella, Parasutterella, and Roseburia in immunocompromised mice. Conversely, the abundances of Helicobacter, Bacteroides, and unclassified_Desulfovibrionaceae were significantly decreased after administration of LRa05. Based on these findings, orally administered LRa05 could effectively maintain intestinal microbiota homeostasis and regulate immunity, suggesting the potential of L. rhamnosus LRa05 as a candidate probiotic strain in the application of dietary supplement. PRACTICAL APPLICATION: Supplement with L. rhamnosus LRa05 can improve immunity, regulate gut microbiota and promote body health.

Cistanche deserticola polysaccharide-functionalized dendritic fibrous nano-silica as oral delivery system for H9N2 vaccine to promote systemic and mucosal immune response

Most infectious diseases are caused by pathogens that invade the body tissues through mucosal tract. Therefore, it is essential to develop effective vaccines administered through the mucosa as a first-line of defense against major infectious diseases. Oral delivery of vaccines is currently of great interest due to its potential to elicit both mucosal and systemic immune responses, high compliance rate and non-invasive nature. However, their development is limited by the challenging gastrointestinal (GI) environment, the low permeability of the mucus barrier, and the lack of effective and safe mucosal adjuvants. Currently, nanoparticle-based strategies show significant potential for improving oral vaccine delivery systems. Herein, the dendritic fibrous nano-silica (DFNS) grafted with Cistanche deserticola polysaccharide (CDP) nanoparticles (CDP-DFNS) were developed for oral delivery of H9N2 antigen. CDP-DFNS induced the activation of macrophages, thereby enhancing antigen uptake in vitro. Additionally, CDP-DFNS/H9N2 significantly activated the dendritic cells (DCs) in Peyer's patches (PPs), and T/B cells in mesenteric lymph nodes (MLNs). Moreover, CDP-DFNS/H9N2 enhanced the HI titers and levels of H9N2-specific antibody IgG, secretory IgA (SIgA) and H9N2-specific IgA in intestinal and respiratory mucosa, as well as Th-associated cytokines. Our results indicate that CDP-DFNS could be a promising oral vaccine adjuvant delivery system.

A dual strain probiotic administered via the waterline beneficially modulates the ileal and cecal microbiome, sIgA and acute phase protein levels, and growth performance of broilers during a dysbacteriosis challenge

Intestinal dysbacteriosis is increasing in broilers due to the reduced use of antibiotics in feed. This study tested the effect of daily waterline administration of a dual-strain probiotic comprising Lactobacillus acidophilus AG01 and Bifidobacterium animalis subspecies lactis AG02, on growth performance and intestinal health during a 3-step microbial challenge. In total, 900 Ross 308 males were assigned to 36 floor pens (25 birds/pen, 12 pens/treatment) in a completely randomized design. Birds were fed a corn, wheat and soybean-meal based diet. Diets were formulated in 3 phases (starter: 1 to 10; grower: 11 to 24; finisher: 25 to 42 d of age). Treatments comprised a non-challenged control (NC), challenged control (CC), and the CC supplemented with 1 × 108 colony forming units (CFU)/bird/day of the probiotic (CC+Probiotic). The challenge comprised 1 × 108 CFU/bird of Avian Pathogenic Escherichia coli on d 7, 4,000 oocysts/bird of Eimeria on d 15 and 1 × 109 CFU/bird of C. perfringens on d 18, 19 and 20. Growth performance was monitored over 42 d, blood samples, and digesta were collected and intestinal dysbacteriosis scoring was performed. Compared to NC birds, CC birds exhibited reduced BW (all phases), reduced feed intake (starter and grower phase), increased FCR (grower phase and overall; P < 0.05), reduced ileal lactic acid bacteria concentrations (d 24 and 42), and increased cecal E. coli (d 24; P < 0.05). Compared to CC birds, CC+Probiotic birds exhibited increased BW, BW gain and feed intake during grower phase (P < 0.05), increased ileal lactic acid bacteria at d 24 and 42 and reduced ileal C. perfringens at d 24, increased mucosal secretory IgA and reduced serum alpha-1-acid-glycoprotein at d 42. The overall growth performance of CC+Probiotic birds was equivalent to NC birds. These results confirm the efficacy of the dual strain probiotic for mitigating the negative effects of a multi-microbial challenge, improving gut health and growth performance in commercial broilers under dysbacteriosis challenge.

Microbe-binding Antibodies in the Female Genital Tract: Associations with the Vaginal Microbiome and Genital Immunology

Bacteria-Ig interactions maintain homeostasis in the gut through the clearance of pathogenic bacteria and the development of immune tolerance to inflammatory bacteria; whether similar interactions modulate inflammation and bacterial colonization in the female genital tract is uncertain. In this study, we used a flow cytometry-based assay to quantify microbe-binding IgA and IgG in the cervicovaginal secretions of 200 HIV-uninfected women from Nairobi, Kenya that were enriched for bacterial vaginosis. Total IgA and IgG were abundant and frequently demonstrated ex vivo binding to the key vaginal bacteria species Gardnerella vaginalis, Prevotella bivia, Lactobacillus iners, and Lactobacillus crispatus, which are largely microbe-specific. Microbe-binding Abs were generally not associated with the presence or abundance of their corresponding bacteria. Total and microbe-binding IgA and IgG were inversely correlated with total bacterial abundance and positively correlated with several proinflammatory cytokines (IL-6, TNF) and chemotactic chemokines (IP-10, MIG, MIP-1α, MIP-1β, MIP-3α, MCP-1, IL-8), independent of total bacterial abundance. Flow cytometry-based quantification of microbe-binding Abs provides a platform to investigate host-microbiota interactions in the female genital tract of human observational and interventional studies. In contrast to the gut, cervicovaginal microbe-binding IgA and IgG do not appear to be immunoregulatory but may indirectly mitigate bacteria-induced inflammation by reducing total bacterial abundance.

Oral Administration of Zinc Sulfate with Intramuscular Foot-and-Mouth Disease Vaccine Enhances Mucosal and Systemic Immunity

Background/Objectives: Foot-and-mouth disease (FMD) remains a significant global threat to livestock farming. Current commercial FMD vaccines present several challenges, including the risk of infection and adverse injection site reactions due to oil-based adjuvants. The complex immune environment of the gut-associated lymphoid tissue has the potential to induce broad and diverse immune responses. Therefore, we aimed to explore the potential of zinc sulfate as an oral adjuvant to enhance intestinal mucosal immunity and complement the effects of intramuscular (IM) FMD vaccination. Methods: We conducted serological analyses on mice and pigs, measuring secretory IgA (sIgA) levels and evaluating the expression of mucosal immunity-related genes in pigs. These assessments were used to investigate the systemic and mucosal immune responses induced by oral zinc sulfate administration in combination with an IM FMD vaccine. Results: This combination strategy significantly increased structural protein antibody titers and virus neutralization titers in experimental animals (mice) and target animals (pigs) across early, mid-, and long-term periods. Additionally, this approach enhanced the expression of key cytokines associated with mucosal immunity and increased sIgA levels, which are critical markers of mucosal immunity. Conclusions: Oral zinc sulfate administration may synergize with inactivated FMD vaccines, leading to sustained and enhanced long-term immune responses. This novel strategy could reduce the frequency of required vaccinations or allow for a lower antigen dose in vaccines, effectively stimulating the mucosal immune system and boosting systemic immunity. This approach has the potential to improve the overall efficacy of commercial FMD vaccines.

Intestinal Permeability In Subjects With Rheumatoid Arthritis: A Critical Therapeutic Priority

Rheumatoid arthritis is increasingly being recognized as the synovial manifestation of a group of systemic autoinflammatory conditions known as immune-mediated inflammatory diseases. While each of these conditions displays unique diagnostic signs and symptoms based on the tissue targeted by inflammation, most immune-mediated inflammatory diseases share common features, including their immune-signaling pathways. Owing to these similarities, great advances have emerged in the past few decades using therapies designed to block downstream inflammatory mediators (eg, cytokine-blocking biologics, Janus Kinase (JAK) inhibitors). Unfortunately, fewer advances have been made in therapies that have the potential to target the upstream antecedents and triggers of these complex inflammatory diseases, such as the immunologic chain of events triggered by intestinal hyperpermeability (ie, leaky gut) or gastrointestinal dysbiosis (ie, alterations in the gut microbiota). In the past few decades, intestinal hyperpermeability has emerged as an important antecedent for a wide range of chronic immunological and metabolic conditions, including celiac disease, obesity, cardiovascular disease, and a number of immune-mediated inflammatory diseases such as inflammatory bowel disease, psoriasis, and rheumatoid arthritis. In this narrative review, we discuss the growing awareness that biomarkers of intestinal permeability are frequently associated with non-gastrointestinal immune-mediated inflammatory diseases, particularly those associated with the gut-joint axis, such as rheumatoid arthritis. We suggest that measures of intestinal permeability, along with lifestyle and nutrient interventions that target gut-barrier function, may be important adjunctive clinical tools to help patients with rheumatoid arthritis achieve and maintain remission.

Immunoglobulin A Antibodies: From Protection to Harmful Roles

Immunoglobulin A (IgA) is the most abundantly produced antibody in humans. IgA is a unique class of immunoglobulin due to its multiple molecular forms, and a defining difference between the two subclasses: IgA1 has a long hinge-region that is heavily O-glycosylated, whereas the IgA2 hinge-region is shorter but resistant to bacterial proteases prevalent at mucosal sites. IgA is essential for immune homeostasis and education. Mucosal IgA plays a crucial role in maintaining the integrity of the mucosal barrier by immune exclusion of pathobionts while facilitating colonization with certain commensals; a large part of the gut microbiota is coated with IgA. In the circulation, monomeric IgA that has not been engaged by antigen plays a discrete role in dampening inflammatory responses. Protective and harmful roles of IgA have been studied over several decades, but a new understanding of the complex role of this immunoglobulin in health and disease has been provided by recent studies. Here, we discuss the physiological and pathological roles of IgA with a special focus on the gut, kidneys, and autoimmunity. We also discuss new IgA-based therapeutic approaches.

Continuous Oral Administration of the Superantigen Staphylococcal Enterotoxin C2 Activates Intestinal Immunity and Modulates the Gut Microbiota in Mice

Staphylococcal Enterotoxin C2 (SEC2), a classical superantigen, is an antitumor immunotherapy agent. However, the injectable formulation of SEC2 limits its clinical application. Here, it is reported that oral administration of SEC2 activates the intestinal immune system and benefits intestinal health in a mouse model. These results indicate that intact SEC2 is detected in the stomach, intestine, and serum after oral administration. Continuous oral administration of SEC2 activates immune cells in gut-associated lymphoid tissues, promoting extensive differentiation and proliferation of CD4+ and CD8+ T cells and CD19+ B cells, leading to increased production of cytokines and secretory immunoglobulin A. SEC2 also enhances intestinal barrier function, as demonstrated by an increased villus length/crypt depth ratio and elevated expression of mucins and tight junction proteins. Additionally, SEC2 indirectly influenced gut microbiota, reinforcing potential probiotics and short-chain fatty acid synthesis. Enhanced differentiation of T and B cells in the spleen, coupled with elevated serum interleukin-2 levels, suggests systemic immune enhancement following oral administration of SEC2. These findings provide a scientific basis for the development of SEC2 as an oral immunostimulant for immune enhancement and anti-tumor immunotherapy.

Leveraging pleiotropy identifies common-variant associations with selective IgA deficiency

Selective IgA deficiency (SIgAD) is the most common inborn error of immunity (IEI). Unlike many IEIs, evidence of a role for highly penetrant rare variants in SIgAD is lacking. Previous SIgAD studies have had limited power to identify common variants due to their small sample size. We overcame this problem first through meta-analysis of two existing GWAS. This identified four novel common-variant associations and enrichment of SIgAD-associated variants in genes linked to Mendelian IEIs. SIgAD showed evidence of shared genetic architecture with serum IgA and a number of immune-mediated diseases. We leveraged this pleiotropy through the conditional false discovery rate procedure, conditioning our SIgAD meta-analysis on large GWAS of asthma and rheumatoid arthritis, and our own meta-analysis of serum IgA. This identified an additional 18 variants, increasing the number of known SIgAD-associated variants to 27 and strengthening the evidence for a polygenic, common-variant aetiology for SIgAD.

Effect of gum Arabic as natural prebiotic on intestinal ecosystem of post-hatched broiler chicks

The purpose of the current study was to investigate the effects of gum Arabic supplementation on short-chain fatty acids, cecal microbiota, immune-related gene expression, and small intestinal morphology in post-hatched broiler chicks. On the day of hatching, four hundred thirty-two commercial male broiler chicks were randomly allocated into six treatments with twelve cages as replicates of six chicks each for 24 days. Dietary treatments (T1 to T6) were supplemented with 0.0, 0.12, 0.25, 0.50, 0.75, and 1.0% gum Arabic to the basal diet, respectively. Performance parameters, short-chain fatty acid concentration, quantification of microbiota and immune response gene expression (pre-inflammatory cytokines, mucin-2, and secretory immunoglobulin A), and histomorphometry of the small intestine were measured. According to our results, daily weight gains in T2 and the production efficiency index increased in T2 to T4, whereas daily feed intake decreased in T2, T3, T5, and T6, but feed conversion ratio improved. Concentration of lactate, acetate, butyrate, and total short-chain fatty acid increased in T2, T3, T5, and T6. Propionate ‎in T2 T3, T4, and T6 and format in T2, T5, and T6 also increased. Lactobacillus spp. quantitatively increased from T3 to T6, whereas Bacteroides spp. decreased in T3 and T5. Other microbiota quantitatively showed no effect of dietary supplements. IL-1β, TNF-α, and MUC-2 decreased in T2 to T6 and IL-12 in T3, whereas INF-Y increased in T4 to T6 and SIgA in T4. All histometeric parameters of the duodenum, jejunum, and ileum improved with dietary supplementation. We conclude that the administration of gum Arabic resulted in an improvement in overall performance, fermentation metabolites, and modification of microbiota and immune response with improved histomorphometry in the intestines of young chicks.

Interferon lambda 4 is a gut antimicrobial protein

To withstand complex microbial challenges, the mammalian gut largely depends on the secretion of diverse antimicrobial proteins. Type III interferons (IFNλs) are ordinarily considered inducible antiviral cytokines involved in intestinal immunity. Unlike other IFNλs, we found that newly identified IFNλ4 is an intestinal antibacterial protein. Large amounts of natural IFNλ4 are present in the secretory layer of the intestinal tracts of healthy piglets, which suggests that IFNλ4 is in direct physiological contact with microbial pathogens. We also identified two biochemical functions of mammalian IFNλ4, the induction of bacterial agglutination and direct microbial killing, which are not functions of the other IFNλs. Further mechanistic investigations revealed that after binding to the carbohydrate fraction of lipopolysaccharide, mammalian IFNλ4 self-assembles into bacteria-surrounding nanoparticles that agglutinate bacteria, and that its unique cationic amphiphilic molecular structure facilitates the destruction of bacterial membranes. Our data reveal features of IFNλ4 distinct from those of previously reported IFNλs and suggest that noncanonical IFNλ4 is deeply involved in intestinal immunity, beyond simply cytokine signaling.

The dynamic crosslinking between gut microbiota and inflammation during aging: reviewing the nutritional and hormetic approaches against dysbiosis and inflammaging

The early-life gut microbiota (GM) is increasingly recognized for its contributions to human health and disease over time. Microbiota composition, influenced by factors like race, geography, lifestyle, and individual differences, is subject to change. The GM serves dual roles, defending against pathogens and shaping the host immune system. Disruptions in microbial composition can lead to immune dysregulation, impacting defense mechanisms. Additionally, GM aids digestion, releasing nutrients and influencing physiological systems like the liver, brain, and endocrine system through microbial metabolites. Dysbiosis disrupts intestinal homeostasis, contributing to age-related diseases. Recent studies are elucidating the bacterial species that characterize a healthy microbiota, defining what constitutes a 'healthy' colonic microbiota. The present review article focuses on the importance of microbiome composition for the development of homeostasis and the roles of GM during aging and the age-related diseases caused by the alteration in gut microbial communities. This article might also help the readers to find treatments targeting GM for the prevention of various diseases linked to it effectively.

A comprehensive update on the immunoregulatory mechanisms of Akkermansia muciniphila: insights into active ingredients, metabolites, and nutrient-driven modulation

Akkermansia muciniphila (A. muciniphila) has gained recognition as a pioneering probiotic, exhibiting considerable potential to enhance immune conditions across both humans and animals. The health benefits of A. muciniphila are attributed to its various components, including outer membrane proteins (PilQ and Amuc_1100), secreted proteins (P9 and AmTARS), extracellular vesicles, and metabolites such as SCFAs, ornithine lipids, γ-aminobutyric acid, cobalamin, and inosine. The dynamic control of the mucus layer by A. muciniphila plays a crucial role in regulating intestinal mucosal immunity. Furthermore, A. muciniphila modulates immune function by interacting with macrophages, dendritic cells, T lymphocytes, and Paneth cells. Increasing the abundance of A. muciniphila in the gut through nutritional strategies represents a safe and effective means to augment immune function. Various polyphenols, oligosaccharides, and polysaccharides have been shown to elevate the levels of this bacterium, thereby contributing to favorable immunoregulatory outcomes. This paper delves into the latest research advancements related to the probiotic mechanisms of A. muciniphila and provides an overview of the current understanding of how its abundance responds to nutrients. These insights offer a theoretical foundation for the utilization of A. muciniphila in immunoregulation.

Cow Placenta Extract Ameliorates Cyclophosphamide-Induced Intestinal Damage by Enhancing the Intestinal Barrier, Improving Immune Function, and Restoring Intestinal Microbiota

Immunosuppression undermines intestinal barrier integrity. Cow placenta extract (CPE) primarily consists of active peptides with immunomodulatory and antioxidant effects. This study aimed to examine the preventive effect of CPE against intestinal damage induced by cyclophosphamide (Cy) in immunosuppressed mice. Thirty-six mice were randomly allocated into three groups: control group (C), model group (M), and treatment group (CPE). The mice in the CPE group were provided with 1500 mg/kg/day of CPE via gavage. In the last 3 days, mice in the groups M and CPE received intraperitoneal injections of 80 mg/kg/day of Cy. The results showed that CPE improved intestinal barrier function by decreasing serum d-Lactate (D-LA) levels and diamine oxidase (DAO) activity, while elevating the relative expression of Occludin, zonula occludens-1 (ZO-1), and mucin-2 (MUC-2) mRNA. Additionally, CPE improved the immune organ index and elevated the levels of secretory immunoglobulin A (sIgA), superoxide dismutase (SOD), interleukin-1beta (IL-1β), interleukin-4 (IL-4), interleukin-10 (IL-10), and tumor necrosis factor-α (TNF-α) in the intestine, thereby enhancing intestinal mucosal immune function. Furthermore, CPE improved the diversity of intestinal microbiota and increased the abundance of Candidatus_Saccharimonas, Psychrobacter, and Enterorhabdus, which promoted the proper functioning of the intestines. These findings suggest that CPE effectively ameliorates Cy-induced intestinal damage by enhancing the intestinal barrier, improving immune function, and restoring intestinal microbiota.

Responses of Intestinal Antioxidant Capacity, Morphology, Barrier Function, Immunity, and Microbial Diversity to Chlorogenic Acid in Late-Peak Laying Hens

This study examined the influence of chlorogenic acid (CGA) on gut antioxidant status, morphology, barrier function, immunity, and cecal microbiota in late-peak laying hens. A total of 240 Hy-Line Brown hens, aged 43 weeks, were randomly assigned to four groups, the basal diet +0, 400, 600, and 800 mg/kg CGA, for 12 weeks. The results revealed that CGA significantly reduced ileal H2O2 and malondialdehyde levels; increased duodenal height, ileal villus height, and villus height-to-crypt depth ratio; while decreasing jejunal crypt depth. The 600 and 800 mg/kg CGA significantly upregulated the duodenal, jejunal, and ileal ZO-1 and occludin gene expression; increased IgG levels in serum and ileum; and upregulated ileal IgA gene expression. The 600 mg/kg CGA significantly upregulated CD3D and CD4 gene expression, while downregulating IL-1β gene expression in duodenum, jejunum, and ileum. Moreover, CGA changed the gut microbiota structure. The SCFA-producing bacteria unclassified_f__Peptostreptococcaceae, unclassified_f_Oscillospiraceae, Pseudoflavonifractor, Lachnospiraceae_FCS020_group, Oscillospira, Elusimicrobium, Eubacterium_ventriosum_group, Intestinimonas, and norank_f_Coriobacteriales_Incertae_Sedis were significantly enriched in the 400, 600, and/or 800 mg/kg CGA groups. The bacteria Lactobacillus, Bacillus, and Akkermansia were significantly enriched in the 600 mg/kg CGA group. Conclusively, dietary CGA (600-800 mg/kg) improved intestinal antioxidant status, morphology, barrier and immune function, and beneficial microbiota growth in late-peak laying hens.

Biogenic Selenium Nanoparticles Synthesized by L. brevis 23017 Enhance Aluminum Adjuvanticity and Make Up for its Disadvantage in Mice

The most popular vaccine adjuvants are aluminum ones, which have significantly reduced the incidence and mortality of many diseases. However, aluminum-adjuvanted vaccines are constrained by their limited capacity to elicit cellular and mucosal immune responses, thus constraining their broader utilization. Biogenic selenium nanoparticles are a low-cost, environmentally friendly, low-toxicity, and highly bioactive form of selenium supplementation. Here, we purified selenium nanoparticles synthesized by Levilactobacillus brevis 23017 (L-SeNP) and characterized them using Fourier-transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, scanning electron microscopy, and transmission electron microscopy. The results indicate that the L-SeNP has a particle size ranging from 30 to 200 nm and is coated with proteins and polysaccharides. Subsequently, we assessed the immune-enhancing properties of L-SeNP in combination with an adjuvant-inactivated Clostridium perfringens type A vaccine using a mouse model. The findings demonstrate that L-SeNP can elevate the IgG and SIgA titers in immunized mice and modulate the Th1/Th2 immune response, thereby enhancing the protective effect of aluminum-adjuvanted vaccines. Furthermore, we observed that L-SeNP increases selenoprotein expression and regulates oxidative stress in immunized mice, which may be how L-SeNP regulates immunity. In conclusion, L-SeNP has the potential to augment the immune response of aluminum adjuvant vaccines and compensate for their limitations in eliciting Th1 and mucosal immune responses.

PCK2 maintains intestinal homeostasis and prevents colitis by protecting antibody-secreting cells from oxidative stress

Maintaining intracellular redox balance is essential for the survival, antibody secretion, and mucosal immune homeostasis of immunoglobulin A (IgA) antibody-secreting cells (ASCs). However, the relationship between mitochondrial metabolic enzymes and the redox balance in ASCs has yet to be comprehensively studied. Our study unveils the pivotal role of mitochondrial enzyme PCK2 in regulating ASCs' redox balance and intestinal homeostasis. We discover that PCK2 loss, whether globally or in B cells, exacerbates dextran sodium sulphate (DSS)-induced colitis due to increased IgA ASC cell death and diminished antibody production. Mechanistically, the absence of PCK2 diverts glutamine into the TCA cycle, leading to heightened TCA flux and excessive mitochondrial reactive oxygen species (mtROS) production. In addition, PCK2 loss reduces glutamine availability for glutathione (GSH) synthesis, resulting in a decrease of total glutathione level. The elevated mtROS and reduced GSH expose ASCs to overwhelming oxidative stress, culminating in cell apoptosis. Crucially, we found that the mitochondria-targeted antioxidant Mitoquinone (Mito-Q) can mitigate the detrimental effects of PCK2 deficiency in IgA ASCs, thereby alleviating colitis in mice. Our findings highlight PCK2 as a key player in IgA ASC survival and provide a potential new target for colitis treatment.

A Critical Review on the Role of Probiotics in Lung Cancer Biology and Prognosis

Lung cancer remains the leading cause of cancer-related deaths worldwide. According to the American Cancer Society (ACS), it ranks as the second most prevalent type of cancer globally. Recent findings have highlighted bidirectional gut-lung interactions, known as the gut-lung axis, in the pathophysiology of lung cancer. Probiotics are live microorganisms that boost host immunity when consumed adequately. The immunoregulatory mechanisms of probiotics are thought to operate through the generation of various metabolites that impact both the gut and distant organs (e.g., the lungs) through blood. Several randomized controlled trials have highlighted the pivotal role of probiotics in gut health especially for the prevention and treatment of malignancies, with a specific emphasis on lung cancer. Current research indicates that probiotic supplementation positively affects patients, leading to a suppression in cancer symptoms and a shortened disease course. While clinical trials validate the therapeutic benefits of probiotics, their precise mechanism of action remains unclear. This narrative review aims to provide a comprehensive overview of the present landscape of probiotics in the management of lung cancer.

Exploring the anti-inflammatory effects of postbiotic proteins from Lactobacillus delbrueckii CIDCA 133 on inflammatory bowel disease model

Lactobacillus delbrueckii CIDCA 133 is a promising health-promoting bacterium shown to alleviate intestinal inflammation. However, the specific bacterial components responsible for these effects remain largely unknown. Here, we demonstrated that consuming extractable proteins from the CIDCA 133 strain effectively relieved acute ulcerative colitis in mice. This postbiotic protein fraction reduced the disease activity index and prevented colon shortening in mice. Furthermore, histological analysis revealed colitis prevention with reduced inflammatory cell infiltration into the colon mucosa. Postbiotic consumption also induced an immunomodulatory profile in colitic mice, as evidenced by both mRNA transcript levels (Tlr2, Nfkb1, Nlpr3, Tnf, and Il6) and cytokines concentration (IL1β, TGFβ, and IL10). Additionally, it enhanced the levels of secretory IgA, upregulated the transcript levels of tight junction proteins (Hp and F11r), and improved paracellular intestinal permeability. More interestingly, the consumption of postbiotic proteins modulated the gut microbiota (Bacteroides, Arkkemansia, Dorea, and Oscillospira). Pearson correlation analysis indicated that IL10 and IL1β levels were positively associated with Bacteroides and Arkkemansia_Lactobacillus abundance. Our study reveals that CIDCA 133-derived proteins possess anti-inflammatory properties in colonic inflammation.

Alteration of gut microbiota in Henoch-Schönlein purpura children with gastrointestinal involvement

BACKGROUND

The compositional and structural changes of gut microbiota were closely related to the status of Henoch-Schönlein purpura (HSP).

AIMS

To investigate if clinical indicators and gut microbiota differ between HSP patients with or without gastrointestinal (GI) involvement and to explore the alterations of fecal microbiota in HSP children with and without GI symptoms.

METHODS

A total of 22 children with HSP were enrolled in the study. Fecal microbiota composition was analyzed by 16S rRNA sequencing. Clinical indicators, fecal microbial diversity, and compositions were compared between the two groups.

RESULTS

Respectively, 9 patients with GI involvement (HSP-A) and 13 patients without GI involvement (HSP-N) were enrolled. Prealbumin (PA) and the ratio of immunoglobulin A (IgA) / complement (C)3 were significantly decreased in the HSP-A group and an elevated D-dimer was found in the HSP-N group. The relative abundances of Blautia, Lachnospira, and Haemophilus were significantly higher in the HSP-A group compared to HSP-N. Lower levels of unidentified Prevotellaceae, Parabacteroides, and Romboutsia were found in HSP-A patients. The linear discriminant analysis effect size (LEfSe) showed that the biomarkers for the HSP-A group included Blautia, Anaerostipes, Veillonella, Lachnospira, and Haemophilus. For the HSP-N group, unidentified Prevotellaceae, Intestinibacter, Romboutsia, and Akkermansia were the prominent biomarkers at the genus level. Additionally, the ratio of IgA/C3 exhibited a negative correlation with the genus Blautia. Meanwhile, PA showed negatively correlation with Veillonella.

CONCLUSIONS

These results provide a broader understanding for future microbial-based therapies to decrease the development of GI involvement and improve the clinical outcome of HSP in children.

Medium- and Long-Term Immune Responses in the Small Intestine in Piglets from Oral Vaccination against Escherichia coli

Post-weaning stress, together with Escherichia coli, are two of the key factors in the occurrence of post-weaning diarrhea. There are different commercial vaccines that induce immunity at the local or systemic level, improving farm health and avoiding economic losses in the pork industry. That is why the objective of this study was to evaluate the effect of an oral enterotoxigenic E. coli F4/F18 vaccine on immunity and intestinal integrity in the middle and long term after inoculation. The gene expression of the biomarkers indicative of cellular infiltration (calprotectin, CAL), tight junction proteins (occludin, OCL; zonulin, ZON; and claudin, CLA) and a panel of proinflammatory (interleukins, IL: IL1α, IL1β, IL6, IL8, IL12p35 and IL12p40; interferons, IFN: IFNα and IFNγ; and tumoral necrosis factor, TNF: TNFα) and anti-inflammatory mediator cytokines (TGFβ and IL10) were analyzed, as well as histomorphology in jejunum and ileum, the cell density of goblet cells, intraepithelial lymphocytes and IgA-producing cells. Differences were observed in ZON, CLA and CAL, with greater gene expression in observed in vaccinated piglets at 42 days post vaccination (dpv) in the ileum. Regarding the expression of cytokines, the vaccinated animals showed significant differences in IL1α, IL6, IL12p35, IL12p40, IFNα, IFNγ, TNFα and TGFβ at 42 dpv in the jejunum or ileum. The villi showed greater height in the vaccinated piglets and the ratio between villus height and crypt depth was significantly greater in the vaccinated group in the jejunum at 84 dpv. The count of IgA-producing cells shows higher values for the unvaccinated group in the ileum, while intraepithelial lymphocytes show a significant increase in both jejunum and ileum in vaccinated piglets. We can conclude that oral vaccination against E. coli produces an evident effect, which manifests itself even in the middle and long term after the challenge, including immune response, decrease in antimicrobials usage, better histological structure in intestine and the improvement of performance.

Role of cellular effectors in the induction and maintenance of IgA responses leading to protective immunity against enteric bacterial pathogens

The mucosal immune system is a critical first line of defense to infectious diseases, as many pathogens enter the body through mucosal surfaces, disrupting the balanced interactions between mucosal cells, secretory molecules, and microbiota in this challenging microenvironment. The mucosal immune system comprises of a complex and integrated network that includes the gut-associated lymphoid tissues (GALT). One of its primary responses to microbes is the secretion of IgA, whose role in the mucosa is vital for preventing pathogen colonization, invasion and spread. The mechanisms involved in these key responses include neutralization of pathogens, immune exclusion, immune modulation, and cross-protection. The generation and maintenance of high affinity IgA responses require a delicate balance of multiple components, including B and T cell interactions, innate cells, the cytokine milieu (e.g., IL-21, IL-10, TGF-β), and other factors essential for intestinal homeostasis, including the gut microbiota. In this review, we will discuss the main cellular components (e.g., T cells, innate lymphoid cells, dendritic cells) in the gut microenvironment as mediators of important effector responses and as critical players in supporting B cells in eliciting and maintaining IgA production, particularly in the context of enteric infections and vaccination in humans. Understanding the mechanisms of humoral and cellular components in protection could guide and accelerate the development of more effective mucosal vaccines and therapeutic interventions to efficiently combat mucosal infections.

Inter-individual and inter-regional variability of breast milk antibody reactivity to bacterial lipopolysaccharides

Breast milk is a vital source of nutrients, prebiotics, probiotics, and protective factors, including antibodies, immune cells and antimicrobial proteins. Using bacterial lipopolysaccharide arrays, we investigated the reactivity and specificity of breast milk antibodies towards microbial antigens, comparing samples from rural Kenya and urban Switzerland. Results showed considerable variability in antibody reactivity both within and between these locations. Kenyan breast milk demonstrated broad reactivity to bacterial lipopolysaccharides, likely due to increased microbial exposure. Antibodies primarily recognized the O-antigens of lipopolysaccharides and showed strong binding to specific carbohydrate motifs. Notably, antibodies against specific Escherichia coli O-antigens showed cross-reactivity with parasitic pathogens like Leishmania major and Plasmodium falciparum, thus showing that antibodies reacting against lipopolysaccharide O-antigens can recognize a wide range of antigens beyond bacteria. The observed diversity in antigen recognition highlights the significance of breast milk in safeguarding infants from infections, particularly those prevalent in specific geographic regions. The findings also offer insights for potential immunobiotic strategies to augment natural antibody-mediated defense against diverse pathogens.

Harnessing the potential of the NALT and BALT as targets for immunomodulation using engineering strategies to enhance mucosal uptake

Mucosal barrier tissues and their mucosal associated lymphoid tissues (MALT) are attractive targets for vaccines and immunotherapies due to their roles in both priming and regulating adaptive immune responses. The upper and lower respiratory mucosae, in particular, possess unique properties: a vast surface area responsible for frontline protection against inhaled pathogens but also simultaneous tight regulation of homeostasis against a continuous backdrop of non-pathogenic antigen exposure. Within the upper and lower respiratory tract, the nasal and bronchial associated lymphoid tissues (NALT and BALT, respectively) are key sites where antigen-specific immune responses are orchestrated against inhaled antigens, serving as critical training grounds for adaptive immunity. Many infectious diseases are transmitted via respiratory mucosal sites, highlighting the need for vaccines that can activate resident frontline immune protection in these tissues to block infection. While traditional parenteral vaccines that are injected tend to elicit weak immunity in mucosal tissues, mucosal vaccines (i.e., that are administered intranasally) are capable of eliciting both systemic and mucosal immunity in tandem by initiating immune responses in the MALT. In contrast, administering antigen to mucosal tissues in the absence of adjuvant or costimulatory signals can instead induce antigen-specific tolerance by exploiting regulatory mechanisms inherent to MALT, holding potential for mucosal immunotherapies to treat autoimmunity. Yet despite being well motivated by mucosal biology, development of both mucosal subunit vaccines and immunotherapies has historically been plagued by poor drug delivery across mucosal barriers, resulting in weak efficacy, short-lived responses, and to-date a lack of clinical translation. Development of engineering strategies that can overcome barriers to mucosal delivery are thus critical for translation of mucosal subunit vaccines and immunotherapies. This review covers engineering strategies to enhance mucosal uptake via active targeting and passive transport mechanisms, with a parallel focus on mechanisms of immune activation and regulation in the respiratory mucosa. By combining engineering strategies for enhanced mucosal delivery with a better understanding of immune mechanisms in the NALT and BALT, we hope to illustrate the potential of these mucosal sites as targets for immunomodulation.

The immune interactions of gut glycans and microbiota in health and disease

The human digestive system harbors a vast diversity of commensal bacteria and maintains a symbiotic relationship with them. However, imbalances in the gut microbiota accompany various diseases, such as inflammatory bowel diseases (IBDs) and colorectal cancers (CRCs), which significantly impact the well-being of populations globally. Glycosylation of the mucus layer is a crucial factor that plays a critical role in maintaining the homeostatic environment in the gut. This review delves into how the gut microbiota, immune cells, and gut mucus layer work together to establish a balanced gut environment. Specifically, the role of glycosylation in regulating immune cell responses and mucus metabolism in this process is examined.