Is the role of IgA in local immunity completely known?

Production of Intestinal Mucins, sIgA, and Metallothionein after Administration of Zinc and Infection of Ascaridia galli in Chickens: Preliminary Data

The effect of inorganic zinc and Ascaridia galli infection was studied on MUC1, MUC2 (mucin), sIgA (secretory immunoglobulin A), and metallothionein in the intestines of broilers. Thirty-five-day-old chickens (n = 24), COBB 500 breed, were included in a 14-day experiment. Chickens were divided into 4 groups of 6 chickens each: control ©, Ascaridia galli (AG), Zinc group (Zn), and combined group (AG + Zn). Samples from the intestine for determination of MUC1, MUC2, sIgA, and metallothionein were taken at 7 and 14 days during necropsy. Samples from the jejunum for determination of MUC1, MUC2, sIgA, and metallothionein were taken at 7 and 14 days during necropsy. The results demonstrated that 12 days’ administration of inorganic zinc increased production of MUC1 (p < 0.0001) and MUC2 (p < 0.001) in the Ascaridia galli-infected group (Ag + Zn) in comparison to control (C). The beneficial effect of zinc was also revealed in the production of sIgA (p < 0.0001) in the combined group (AG + Zn) at 7 days. The concentration of metallothionein increased mainly in the zinc group (p < 0.01) of first sampling and was upregulated in Zn and AG + Zn groups. The obtained data indicate the use of inorganic zinc as a suitable immunomodulator of intestinal immunity in Ascaridia galli-infected chickens.

Effect of Azomite on growth performance, immune function and tibia breaking strength of broiler chickens during starter period

This study was examined to investigate the effect of Azomite (AZO) on the growth performance, immune function, and bone mineralization of broiler chickens. A total of 240-d old male chicks were randomly assigned into four treatments with six replicates (n = 10), which included control (basal diet), basal diet +0.25% AZO, basal diet + 0.50% AZO and basal diet + kitasamycin as antibiotic growth promoter (AGP). The results indicate that live body weight (LBW), average daily gain (ADG) and feed conversion ratio (FCR) were significantly (p < .05) improved in AZO 0.25% and 0.50% than the control. The weight of bursa of Fabricus was significantly (p < .05) higher in AZO-0.25% and AZO-0.50% than control. Total protein (TP), globulin, IgA and IgG levels were significantly (p < .05) increased with AZO supplemented treatments. Tibia diameter tibia breaking strength was significantly (p < .05) increased in AZO- 0.25% and AZO-0.50% treatment. In conclusion, the results indicated that addition of AZO at the doses of 0.25% and 0.50% in the diet had beneficial effects on growth performance, immune functions and tibia breaking strength.

Effects of Taraxacum mongolicum Hand.-Mazz. (dandelion) on growth performance, expression of genes coding for tight junction protein and mucin, microbiota composition and short chain fatty acids in ileum of broiler chickens

Background

Dandelion is becoming an exploitable alternative to the widely prohibited antibiotics in the poultry production. This research aimed to investigate the effects of dandelion on the growth performance and intestinal barrier function of broiler chickens maintained under standard condition of management. One-hundred and sixty 1-day-old Arbor Acres (AA) male broiler chickens were randomly divided into four groups, with five replicates of eight birds each. The birds were fed a basal diet supplemented without (control group, [CON]) or with 500 (low dose [LD]) or 1000 (high dose [HD]) mg/kg dandelion or with 250 mg/kg chlortetracycline 20% premix (CTC) for 42 days, including the starter phase (d 1 to 21) and the grower phase (d 22 to 42). Body weight (BW) of each bird and feed consumption of each replicate were measured at d 21 and d 42. The ileal tissues were collected on day 21 and 42 to determine expression of genes coding for tight junction protein and mucin as well as ELISA analysis for immune factor. The ileal digesta was collected for microbiota and short chain fatty acids analysis.

Results

Compared with CON group, during day 1–21, the average daily feed intake (ADFI) and feed/gain ratio (F/G) of LD group were lower (P < 0.05); during day 22–42, the F/G of LD and CTC group tended to be lower (P = 0.07); during the overall phase, the ADFI of HD and CTC groups were decreased (P < 0.05), and the F/G of dandelion and CTC groups tended to be decreased (P = 0.07). On day 21, the relative mRNA expression of claudin, occludin-1 and mucin1 in dandelion groups were up-regulated (P < 0.05), and the ZO-1 mRNA expression in CTC group was increased (P < 0.05); on day 42, the claudin and mucin1 transcripts in LD group and ZO-1 transcripts in HD and CTC group were up-regulated (P < 0.05), while the occludin-1 and mucin1 transcripts in CTC group was significantly down-regulated (P < 0.05). In addition, the contents of TNF-α in dandelion groups were lower than that in CTC group (P < 0.05). In the analysis of ileal microbiota, on day 21, decreased α-diversity was observed in HD and CTC groups (P < 0.05). Meanwhile, on day 21, the relative abundance of Firmicutes in dandelion groups tended to be higher (P = 0.09), the relative abundance of Lactobacillus in LD and CTC group were increased (P < 0.05), while Bacteroidete, Bacteroides, and Alistipes relative abundance in dandelion and CTC groups were decreased (P < 0.05). On day 42, the Actinobacteriota relative abundance in CTC group tended to be higher (P = 0.05), and Lysinibacillus relative abundance of CTC group was higher (P = 0.02). Compared with CON group, on day 21, the propionic acid and butyric acid content in CTC group were higher, the butyric acid content in HD group was lower (P < 0.10).

Conclusion

In summary, dietary dandelion supplementation at 500 mg/kg of diet enhanced growth performance of broilers by improving the intestinal barrier function. Dandelion can be supplemented in the diet as an antibiotics alternative to enhance production in poultry industry.

Engineered Nanoparticles inside a Microparticle Oral System for Enhanced Mucosal and Systemic Immunity

Antigen delivery through an oral route requires overcoming multiple challenges, including gastrointestinal enzymes, mucus, and epithelial tight junctions. Although each barrier has a crucial role in determining the final efficiency of the oral vaccination, transcytosis of antigens through follicle-associated epithelium (FAE) represents a major challenge. Most of the research is focused on delivering an antigen to the M-cell for FAE transcytosis because M-cells can easily transport the antigen from the luminal site. However, the fact is that the M-cell population is less than 1% of the total gastrointestinal cells, and most of the oral vaccines have failed to show any effect in clinical trials. To challenge the current dogma of M-cell targeting, in this study, we designed a novel tandem peptide with a FAE-targeting peptide at the front position and a cell-penetrating peptide at the back position. The tandem peptide was attached to a smart delivery system, which overcomes the enzymatic barrier and the mucosal barrier. The result showed that the engineered system could target the FAE (enterocytes and M-cells) and successfully penetrate the enterocytes to reach the dendritic cells located at the subepithelium dome. There was successful maturation and activation of dendritic cells in vitro confirmed by a significant increase in maturation markers such as CD40, CD86, presentation marker MHC I, and proinflammatory cytokines (TNF-α, IL-6, and IL-10). The in vivo results showed a high production of CD4+ T-lymphocytes (helper T-cell) and a significantly higher production of CD8+ T-lymphocytes (killer T-cell). Finally, the production of mucosal immunity (IgA) in the trachea, intestine, and fecal extracts and systemic immunity (IgG, IgG1, and IgG2a) was successfully confirmed. To the best of our knowledge, this is the first study that designed a novel tandem peptide to target the FAE, which includes M-cells and enterocytes rather than M-cell targeting and showed that a significant induction of both the mucosal and systemic immune response was achieved compared to M-cell targeting.

The Effect of Oral Probiotics (Streptococcus Salivarius k12) on the Salivary Level of Secretory Immunoglobulin A, Salivation Rate, and Oral Biofilm: A Pilot Randomized Clinical Trial

We aimed to assess the effect of oral probiotics containing the Streptococcus salivarius K12 strain on the salivary level of secretory immunoglobulin A, salivation rate, and oral biofilm. Thirty-one consenting patients meeting the inclusion criteria were recruited in this double-blind, placebo-controlled, two-arm, parallel-group study and randomly divided into probiotic (n = 15) and placebo (n = 16) groups. Unstimulated salivation rate, concentration of salivary secretory immunoglobulin A, Turesky index, and Papillary-Marginal-Attached index were assessed after 4 weeks of intervention and 2 weeks of washout. Thirty patients completed the entire study protocol. We found no increase in salivary secretory immunoglobulin A levels and salivary flow rates in the probiotic group compared with placebo. Baseline and outcome salivary secretory immunoglobulin A concentrations (mg/L) were 226 ± 130 and 200 ± 113 for the probiotic group and 205 ± 92 and 191 ± 97 for the placebo group, respectively. A significant decrease in plaque accumulation was observed in the probiotic group at 4 and 6 weeks. Within the limitations of the present study, it may be concluded that probiotic intake (Streptococcus salivarius K12) does not affect salivation rates and secretory immunoglobulin A salivary levels but exhibits a positive effect on plaque accumulation. Trial registration NCT05039320. Funding: none.

Dysregulation of murine immune functions on inhalational exposure to ammonia, dimethyl disulfide, 3-methylindole, or propionic acid

Animal husbandry workers are exposed to various malodorous compounds in the workplace. Although these compounds cause severe nuisance, no systemic investigation of their effects on the immune system has been conducted. To address this issue, we evaluated the effects of inhalational exposure to ammonia, dimethyl disulfide, 3-methylindole (3-MI), and propionic acid (PA), representing four major groups of malodorous compounds, on humoral and cellular immunity in mice. Mice were exposed to the substances (low dose: 10 µL and high dose: 200 µL) for 10 min/day for 4 weeks in a modified standard mouse cage. Neutrophil% and splenic cytotoxic T cell% were significantly lower in the high-dose ammonia group than in the vehicle control. Exposure to ammonia and 3-MI increased immature thymic T lymphocyte% relative to control and concomitantly decreased both mature helper and cytotoxic T-cell populations in the thymus. In the ammonia exposure group, levels of serum immunoglobulin E and immunoglobulin A were elevated, and the IgG2a:IgG1 ratio in the serum was reduced in a dose-dependent manner. Splenic natural killer cell activity was significantly less in the PA exposure group than in the control. Overall, our findings suggest that inhalational exposure to these malodorous substances disturbs immune homeostasis in vivo.

Detailed Structure and Pathophysiological Roles of the IgA-Albumin Complex in Multiple Myeloma

Immunoglobulin A (IgA)-albumin complexes may be associated with pathophysiology of multiple myeloma, although the etiology is not clear. Detailed structural analyses of these protein-protein complexes may contribute to our understanding of the pathophysiology of this disease. We analyzed the structure of the IgA-albumin complex using various electrophoresis, mass spectrometry, and in silico techniques. The data based on the electrophoresis and mass spectrometry showed that IgA in the sera of patients was dimeric, linked via the J chain. Only dimeric IgA can bind to albumin molecules leading to IgA-albumin complexes, although both monomeric and dimeric forms of IgA were present in the sera. Molecular interaction analyses in silico implied that dimeric IgA and albumin interacted not only via disulfide bond formation, but also via noncovalent bonds. Disulfide bonds were predicted between Cys34 of albumin and Cys311 of IgA, resulting in an oxidized form of albumin. Furthermore, complex formation prolongs the half-life of IgA molecules in the IgA-albumin complex, leading to excessive glycation of IgA molecules and affects the accumulation of IgA in serum. These findings may demonstrate why complications such as hyperviscosity syndrome occur more often in patients with IgA dimer producing multiple myeloma.

Association between salivary s-IgA concentration and dental caries: A systematic review and meta-analysis

OBJECTIVE

To determine the levels of s-IgA in saliva of caries patients and healthy controls, and to evaluate whether there is a correlation between it and caries by systematic review and meta-analysis.

METHODS

 Eight databases were searched initially in April 2020 and repeated in August 2020. Two independent evaluators screened the literature and extracted the data according to the inclusion and exclusion criteria. I2 test was commonly reflected the heterogeneity. Subgroup analysis and meta-regression analysis explore the sources of heterogeneity. Sensitivity analysis, funnel diagram, Begg's rank correlation and Egger's linear regression were used to determine the possibility of publication bias.

RESULTS

A total of 30 case-control studies were included, with a total sample size of 1545 patients, including 918 caries patients and 627 healthy controls. Salivary s-IgA levels in caries patients were significantly lower than those in healthy controls. In addition, the results of subgroup analysis showed that the significant decrease of salivary s-IgA level was correlated with children patients, mixed dentition and Asian people. The funnel diagram included in the study was symmetrically distributed, and the sensitivity analysis confirmed the robustness of the results.  Conclusion: Salivary s-IgA levels in caries patients were significantly lower than in healthy controls. It has also been demonstrated that salivary s-IgA may be used as an alternative measure to identify subjects at risk of caries susceptibility, suggesting that salivary s-IgA may be a protective factor for dental caries.

Influence of Lacto-Immuno-Vital on growth performance and gene expression of IgA, MUC-2, and growth factor IGF-2 in the jejunum of broiler chickens

The effects of Lacto-Immuno-Vital synbiotic preparation on gene expression of IgA, MUC-2, and growth factor IGF-2 in the jejunum and on BW gain in broiler chickens were studied. A flock of 64,400 1-day-old Hybrid ROSS 308 chickens was inducted in the 42-day experiment. The chickens were divided into 2 equally size groups in separate halls. The chickens in the experimental (E) group received 500 g of Lacto-Immuno-Vital in 1,000 L of drinking water. The preparation was administered daily from the first day (day 1) to day 7 of the experiment. From day 7 to day 22, it was given in pulsed manner (every third day) at a dose of 300 g in 1,000 L of drinking water. The broiler chickens in the E group gained more weight (P < 0.001) compared with control from day 10 to day 42. Death of animals during feeding period was 1,078 chickens in the E group compared with 1,115 dead chickens in the control group. Feed conversion ratio was 1.61 kg of supplemented diet/kg of BW in the E group compare with 1.67 kg of nonsupplemented diet/kg of BW in control. The relative expression of IgA gene in the jejunum was upregulated on day 22 in the E group compared with control (P < 0.05), whereas relative expression of MUC-2 gene was upregulated in the E group compared with control on day 8 and day 22 (P < 0.05; P < 0.001). Similarly, relative expression of IGF-2 gene was upregulated in the E group compared with control on both samplings (P < 0.01). The composition of Lacto-Immuno-Vital synbiotic preparation showed beneficial effects on growth performance, feed conversion ratio, morbidity, mortality, and selected parameters of mucosal immunity in the chicken jejunum.

Infectious disease antibodies for biomedical applications: A mini review of immune antibody phage library repertoire

Antibody phage display is regarded as a critical tool for the development of monoclonal antibodies for infectious diseases. The different classes of antibody libraries are classified based on the source of repertoire used to generate the libraries. Immune antibody libraries are generated from disease infected host or immunization against an infectious agent. Antibodies derived from immune libraries are distinct from those derived from naïve libraries as the host's in vivo immune mechanisms shape the antibody repertoire to yield high affinity antibodies. As the immune system is constantly evolving in accordance to the health state of an individual, immune libraries can offer more than just infection-specific antibodies but also antibodies derived from the memory B-cells much like naïve libraries. The combinatorial nature of the gene cloning process would give rise to a combination of natural and un-natural antibody gene pairings in the immune library. These factors have a profound impact on the coverage of immune antibody libraries to target both disease-specific and non-disease specific antigens. This review looks at the diverse nature of antibody responses for immune library generation and discusses the extended potential of a disease-specified immune library in the context of phage display.

Effects of GABA Supplementation on Intestinal SIgA Secretion and Gut Microbiota in the Healthy and ETEC-Infected Weanling Piglets

Pathogenic enterotoxigenic Escherichia coli (ETEC) has been considered a major cause of diarrhea which is a serious public health problem in humans and animals. This study was aimed at examining the effect of γ-aminobutyric acid (GABA) supplementation on intestinal secretory immunoglobulin A (SIgA) secretion and gut microbiota profile in healthy and ETEC-infected weaning piglets. A total of thirty-seven weaning piglets were randomly distributed into two groups fed with the basal diet or supplemented with 40 mg·kg-1 of GABA for three weeks, and some piglets were infected with ETEC at the last week. According to whether ETEC was inoculated or not, the experiment was divided into two stages (referred as CON1 and CON2 and GABA1 and GABA2). The growth performance, organ indices, amino acid levels, and biochemical parameters of serum, intestinal SIgA concentration, gut microbiota composition, and intestinal metabolites were analyzed at the end of each stage. We found that, in both the normal and ETEC-infected piglets, jejunal SIgA secretion and expression of some cytokines, such as IL-4, IL-13, and IL-17, were increased by GABA supplementation. Meanwhile, we observed that some low-abundance microbes, like Enterococcus and Bacteroidetes, were markedly increased in GABA-supplemented groups. KEGG enrichment analysis revealed that the nitrogen metabolism, sphingolipid signaling pathway, sphingolipid metabolism, and microbial metabolism in diverse environments were enriched in the GABA1 group. Further analysis revealed that alterations in microbial metabolism were closely correlated to changes in the abundances of Enterococcus and Bacteroidetes. In conclusion, GABA supplementation can enhance intestinal mucosal immunity by promoting jejunal SIgA secretion, which might be related with the T-cell-dependent pathway and altered gut microbiota structure and metabolism.

Optimal Criteria for the Selection of Probiotics, Based on their Mode of Action

The objective of this review was to discuss some of the criteria which influence the selection of microorganisms with probiotic properties based on their mode of action. The most common bacteria that belong to the “group” probiotics are the Lactobacillus and Bifidobacterium species/strains. Probiotics have benefits and effects by their mechanism of action in different axial locations such as: producing substances, influencing immune function and response, modification as well as maintenance of a healthy population of microorganisms in the intestinal environment. Probiotics have demonstrated significant potential as therapeutic options for a variety of diseases Potential peripheral pathways that link probiotic ingestion in the brain function are focused on the role of the vagal afferent nerve signalling and changes in the cerebral levels of neuromodulators. The application of probiotic microorganisms represents a way to effectively influence the composition of the intestinal microbiome and the immune system of the host, as well as they can be considered as a suitable alternative to influence a healthy quality of life.

Direct-fed glucose oxidase and its combination with B. amyloliquefaciens SC06 on growth performance, meat quality, intestinal barrier, antioxidative status, and immunity of yellow-feathered broilers

This experiment investigated the effects of dietary glucose oxidase (GOD) and its combination with B. amyloliquefaciens SC06 (BaSC06) on the growth performance, meat quality, intestinal physical barrier, antioxidative status and immunity of male Lingnan yellow-feathered broilers. A total of 720 1-d-old broilers were assigned into 4 treatments with 6 replicates per treatment (30 birds per replicate): (1) basal diet (Ctr), (2) basal diet with 200 mg/kg enramycin (ER), (3) basal diet with 75 U/kg GOD, and (4) GOD diet (75U/kg) supplemented with 1 × 105 colony-forming units BaSC06/kg feed (GB), for an experimental duration of 52 d. The results showed that there were no significant effects of GOD or GB on growth performance of birds. The shear force and drip loss of breast muscle of birds fed GOD and GB were less than those fed ER, while the shear force in GB significantly decreased compared to Ctr. Also, both GOD and GB treatment increased about 1-fold expression of ZO-1, Claudin-1, Occludin, and MUC-2 genes in jejunal mucosa compared to Ctr, no difference was found between GOD and GB. Compared to Ctr, serum total antioxidant capability and glutathione peroxidase in GOD and GB increased, while the malondialdehyde level and xanthine oxidase activity significantly decreased. Both GOD and GB treatments reduced the relative level of HO-1, p53, and BAX transcripts in liver. It is worth noting that GB decreased transcription of p53 and Bcl-2 by 76.11% and 50.19% compared to GOD, respectively. In addition, compared to Ctr, GOD and GB markedly increased serum IL-2 content by 110% and 182%, while decreased IFN-γ by 43.57% and 57.51%, respectively. The highest sIgA level in GB was found among four groups. In conclusion, dietary treatment with GOD and its combination with BaSC06 both had beneficial effects on shear force and drip loss, expression of intestinal tight junctions, antioxidative capacity and immune function. It is suggested that GB had better effect than GOD on anti-apoptosis.