Secretory IgA Levels Research Articles

Impact of Cesarean Delivery and Breastfeeding on Secretory Immunoglobulin A in the Infant Gut Is Mediated by Gut Microbiota and Metabolites

How gut immunity in early life is shaped by birth in relation to delivery mode, intrapartum antibiotic prophylaxis (IAP) and labor remains undetermined. We aimed to address this gap with a study of secretory Immunoglobulin A (SIgA) in the infant gut that also tested SIgA-stimulating pathways mediated by gut microbiota and metabolites. Among 1017 Canadian full-term infants, gut microbiota of fecal samples collected at 3 and 12 months were profiled using 16S rRNA sequencing; C. difficile was quantified by qPCR; fecal metabolites and SIgA levels were measured by NMR and SIgA enzyme-linked immunosorbent assay, respectively. We assessed the putative causal relationships from birth events to gut microbiota and metabolites, and ultimately to SIgA, in statistical sequential mediation models, adjusted for maternal gravida status in 551 infants. As birth mode influences the ability to breastfeed, the statistical mediating role of breastfeeding status and milk metabolites was also evaluated. Relative to vaginal birth without maternal IAP, cesarean section (CS) after labor was associated with reduced infant gut SIgA levels at 3 months (6.27 vs. 4.85 mg/g feces, p < 0.05); this association was sequentially mediated through gut microbiota and metabolites of microbial or milk origin. Mediating gut microbiota included Enterobacteriaceae, C. difficile, and Streptococcus. The milk or microbial metabolites in CS-SIgA mediating pathways were galactose, fucose, GABA, choline, lactate, pyruvate and 1,2-propanediol. This cohort study documented the impact of birth on infant gut mucosal SIgA. It is the first to characterize gut microbe-metabolite mediated pathways for early-life SIgA maturation, pathways that require experimental verification.

Immunochemical, cytogenetic changes and genetic polymorphism in children living under the exposure to unfavourable environmental factors

Introduction. Studies of biomarkers of effects of susceptibility and sensitivity of the human body to exposure to environmental toxicants are a priority in the development of the hygiene science, individual predisposition to adverse effects of chemicals on DNA and the immune system being of special importance. The objective of our study was to assess immunochemical, cytogenetic changes and genetic polymorphism in children exposed to environmental hazards. Materials and methods. We examined immunochemical marker and functional metabolic changes in selected cells, indicators of the adaptive status of the body and xenogenic poisoning of children environmentally exposed to heavy metals. Gene polymorphism was determined by two detoxification genes (GSTP1 and SOD2). Poisoning was assessed by blood levels of heavy metals. Results. We revealed the presence of autoantibodies to the liver and nervous system in 100% of children. A low level of secretory IgA was observed in 27% of children. The salivary lysozyme level indicates a decrease in the protective function of local immunity by 37.9%. We established a direct relationship between the blood levels of heavy metals and genetic instability in somatic cells of the buccal epithelium. The Ile105Val polymorphism of the GSTP1 gene and the Ala16Val polymorphism of the SOD2 gene were found in 45.9% and 28.4% of children, respectively. Limitations. The paper presents the results of a survey of 3 to 6 years children with allergies attending one preschool. The absence of a control cohort prevents us from comparing our findings with those that could have been obtained for children without allergies and/or living in pollution-free areas. Conclusion. The immunochemical and cytogenetic changes, as well as the genetic polymorphism observed in children are most likely associated with adverse health effects of environmental hazards.

Microbial Distribution and Secretory IgA Level among Crossbite Patients at an Early Stage of Comprehensive Orthodontic Treatment

Background: Crossbite is any discrepancy in the relationship between the upper and lower teeth. Crossbites have a relationship with oral microorganisms, such as S. mutans and lactobacillus infections. Viral infections can spread to the oral cavity especially its soft tissue especially herpes simplex virus &amp; cytomegalovirus. Secretory immunoglobulin represents a factor for acquired immunity in the oral cavity which is associated with oral infection and variation. Objectives: Isolation of microbes from crossbite patients, identifying by molecular techniques, determining sIgA level, and selecting appropriate antibiotics for the most common microbe. Materials and Methods: A total of 60 (30 samples of saliva and swab before Orthodontic Treatment and 30 samples of saliva after Orthodontic) during the period from October 2021 to April 2022, Sample were taken from patients and microbiological identification by microscopical and biochemical tests. An antibiotic sensitivity test for S. mutans. Genetic identification was detected in the S. mutans samples by using specificity Sm479 primers, and HCMV primers for cytomegalovirus. Secretory IgA was determined by ELISA Kit. Results: A number of gram-positive bacteria were more than gram-negative (51% and 49%) respectively. The S. mutans and Lactobacillus are the most frequent among the other species, followed by Candida, Klebsiella, and S. epidermidis. 53% in male, while 47% in female, and age group (13­15) was the most prevalent among samples 53%. Regarding S. mutans, the highest sensitive rate is Erythromycin 81%, followed by Amoxiclav 57%, Vancomycin 52%, and Nalidixic acid 43%. Conclusion: Most infectious cases were in ages (14-15) years. S. mutans is more prevalent among bacterial infections, molecular detection by PCR more specifically for S.mutans and CMV virus, sIgA level non-significant inverse correlations between age and sIgA level before treatment, while significant inverse correlation between age and sIgA level after treatment, and S. mutans, reported the highest sensitive rate is Erythromycin (81%), followed by Amoxiclav, Vancomycin, and Nalidixic acid.

Intranasal immunisation with recombinant Toxoplasma gondii uridine phosphorylase confers resistance against acute toxoplasmosis in mice.

Toxoplasmosis is caused by Toxoplasma gondii, which infects all warm-blooded animals, including humans. Currently, control measures for T. gondii infection are insufficient due to the lack of effective medications or vaccines. In this paper, recombinant T. gondii uridine phosphorylase (rTgUPase) was expressed in Escherichia coli and purified via Ni2+-NTA agarose. rTgUPase was inoculated intranasally into BALB/c mice, and the induced immune responses were evaluated by mucosal and humoral antibody and cytokine assays and lymphoproliferative measurements. Moreover, the protective effect against the T. gondii RH strain infection was assessed by calculating the burdens of tachyzoites in the liver and brain and by recording the survival rate and time. Our results revealed that mice immunised with 30μg rTgUPase produced significantly higher levels of secretory IgA (sIgA) in nasal, intestinal, vaginal and vesical washes and synthesised higher levels of total IgG, IgG1 and, in particular, IgG2a in their blood sera. rTgUPase immunisation increased the production of IFN-gamma, interleukin IL-2 and IL-4, but not IL-10 from isolated mouse spleen cells and enhanced splenocyte proliferation in vitro. rTgUPase-inoculated mice were effectively protected against infection with the T. gondii RH strain, showing considerable reduction of tachyzoite burdens in liver and brain tissues after 30 days of infection, and a 44.29% increase in survival rate during an acute challenge. The above findings show that intranasal inoculation with rTgUPase provoked mucosal, humoral and cellular immune responses and indicate that rTgUPase might serve as a promising vaccine candidate for protecting against toxoplasmosis.

Dynamics of clinical symptoms and secretory immunoglobulin a in COVID-19 convalescent patients

The post-COVID-19 recovery period is characterized by persistence of some symptoms, with immunological alterations being of great importance. Development of preventive measures to normalize mucosal immunity after a coronavirus infection determines the relevance of the current study. The aim was to study dynamics of clinical symptoms and level of secretory immunoglobulin A in individuals after a novel coronavirus infection as well as evaluate effectiveness of using IFNa-2b. Materials and methods. A study was conducted with patients aged 18 to 60 years old (n = 130), surveyed 1 to 9 months after post-infection, as well as in apparently healthy individuals lacking COVID-19 (n = 15). Previous novel coronavirus infection and post-COVID manifestations were verified based on medical documentation, complaints, anamnesis data, physical examination and questionnaires. The concentration of salivatory and nasopharyngeal mucosal sIgA was measured dynamically prior to and after administration of local therapy with IFNa-2b (gel applied intranasally twice a day for 30 days). Results. The acute period of COVID-19 was characterized by fever, anosmia, severe asthenia (fatigue and weakness), muscle and joint pain. Among the post-COVID manifestations at early period (13 months), pain in the joints and muscles (75.0%) as well as elevated body temperature (21.2%) were reliably detected, whereas in the long period (69 months) there were revealed dominance with the same frequency of shortness of breath, muscle and joint pain (75.8%, respectively). Based on examination data in healthy subjects, there was determined an arbitrary normal range of secretory IgA in saliva 6.451.81 mg/ml and nasal swabs 13.433.24 mg/ml. In the group of patients 13 months post-infection, therapy with IFNa-2b one month later resulted in significantly increased level of secretory IgA in saliva (from 1.840.28 to 5.781.96 mg/ml) and in nasal swabs (from 28.613.0 to 39.833.85 mg/ml) by more than 3- and 1.5-fold, respectively. In the group of patients without therapy was featured with stably sustained decline in sIgA level up to 9 months after COVID-19. In particular, the level of saliva sIgA ranged from 2.360.56 down to 2.160.66 mg/ml, and in nasal smears from 15.661.32 to 10.231.07 mg/ml that differed insignificantly compared to baseline level. The rate of respiratory diseases prevailed in this group (27.6% of cases), which fully lacked in the group of topically administered IFNa-2b. Conclusion. In the post-COVID period, multiple organ disorders persist and reduced sIgA level is registered. Intranasally applied IFNa-2b made possible to normalize sIgA level and prevent accumulation of respiratory infectious pathologies.

Longitudinal Study of the Effects of Flammulina velutipes Stipe Wastes on the Cecal Microbiota of Laying Hens.

Because antibiotics have been phased out of use in poultry feed, measures to improve intestinal health have been sought. Dietary fiber may be beneficial to intestinal health by modulating gut microbial composition, but the exact changes it induces remain unclear. In this study, we evaluated the effect of Flammulina velutipes stipe wastes (FVW) on the cecal microbiotas of laying chickens at ages spanning birth to 490 days. Using clonal sequencing and 16S rRNA high-throughput sequencing, we showed that FVW improved the microbial diversity when they under fluctuated. The evolvement of the microbiota enhanced the physiological development of laying hens. Supplementation of FVW enriched the relative abundance of Sutterella, Ruminiclostridium, Synergistes, Anaerostipes, and Rikenellaceae, strengthened the positive connection between Firmicutes and Bacteroidetes, and increased the concentration of short-chain fatty acids (SCFAs) in early life. FVW maintains gut microbiota homeostasis by regulating Th1, Th2, and Th17 balance and secretory IgA (S-IgA) level. In conclusion, we showed that FVW induces microbial changes that are potentially beneficial for intestinal immunity. IMPORTANCE Dietary fiber is popularly used in poultry farming to improve host health and metabolism. Microbial composition is known to be influenced by dietary fiber use, although the exact FVW-induced changes remain unclear. This study provided a first comparison of the effects of FVW and the most commonly used antibiotic growth promoter (flavomycin) on the cecal microbiotas of laying hens from birth to 490 days of age. We found that supplementation with FVW altered cecal microbial composition, thereby affecting the correlation network between members of the microbiota, and subsequently affecting the intestinal immune homeostasis.

Intake of Lactobacillus paragasseri SBT2055 improves subjective symptoms of common cold during winter season in healthy adults: A randomized, double-blind, placebo-controlled parallel-group comparative study.

Lactobacillus paragasseri SBT2055 (LG2055) has been reported to show immunostimulating effects. This study aimed to investigate the effects of LG2055 on the subjective symptoms of the physical condition in healthy adults. In this randomized, double-blind, placebo-controlled, parallel-group comparative study, Japanese individuals aged 20-64 years were recruited. A total of 200 participants were randomly divided into two groups by an independent controller (LG2055 and placebo groups; 100 participants per group). Drinkable yogurts containing LG2055 or lacking LG2055 (placebo) were used as test samples. The participants ingested one bottle of the test sample once a day for 12 weeks. A daily physical health questionnaire survey (about common cold symptoms) was performed as the primary outcome, and immunological and oxidative stress markers in saliva and serum were evaluated as secondary outcomes. In total, 198 participants completed the scheduled intake of the test samples, and five participants were excluded from the final analysis. Consequently, 193 participants (LG2055 group, n = 97; placebo group, n = 96) in the Per-Protocol Set were included in the efficacy analysis. The cumulative days of each symptom were evaluated, and the LG2055 group showed a significantly higher ratio of "without symptom" in runny nose, plugged nose, sneezing, sore throat, hoarseness, cough, headache, feeling tired, and fever than the placebo group, indicating that the incidence rates of common cold symptoms were lower in the LG2055 group. Additionally, changes in the salivary secretory IgA levels were significantly higher, and the serum derivatives of reactive oxygen metabolites levels were significantly lower in the LG2055 group. Our study revealed that intake of LG2055 decreased common cold symptoms and improved immune parameters in healthy adults. This suggests that LG2055 contributes to the maintenance of physical conditions by improving the host immune system. [https://www.umin.ac.jp/ctr/index.htm], identifier [UMIN000045901].

Salivary Aspartate Aminotransferase, Alanine Aminotransferase and IgA as biomarkers for Type I Diabetes Mellitus: A Systematic Review

Introduction: Type I diabetes mellitus (T1DM) is an autoimmune disorder characterized by absolute insulin deficiency, which is caused by progressive destruction of the β-islet cells of the pancreas. Aminotransferases participate in the interconversion of amino acids and oxalic acids by transfer of amino groups. Organ damage leads to leakage of transaminases into the blood. IgA is the only immunoglobulin that is found in saliva and forms the first line of defense. Alteration in the levels of secretory IgA often indicates a local or systemic disease. The aim of this systematic review is to evaluate the role of salivary aspartate aminotransferase (AST), alanine aminotransferase (ALT), and IgA as biomarkers for T1DM patients. Materials and Methods: An electronic literature search was conducted by two independent reviewers using PubMed, Medline and Google scholar without any date filter. The inclusion criteria included case control and cross-sectional studies. Publications in languages other than English, review articles, letters to the editor, and studies done on animal models were excluded from the review. The difference in the levels of salivary AST, ALT, or IgA in T1DM patients and in healthy individuals were compared. Risk of bias assessment was done using the ROBINS-I tool. Results: A total of eight relevant articles were assessed, out of which three studies showed elevated salivary AST and ALT levels and five studies showed elevated salivary IgA levels in patients with T1DM. Conclusion: Our review reflected that salivary AST, ALT, and IgA were elevated in T1DM patients, and they can be used for monitoring these patients. Further studies are needed to establish the diagnostic accuracy of these parameters for clinical application.

Porcine Interleukin-17 and 22 Co-Expressed by Yarrowia lipolytica Enhance Immunity and Increase Protection against Bacterial Challenge in Mice and Piglets

Drug resistance in economic animals to pathogens is a matter of widespread concern due to abuse of antibiotics. In order to develop a safe and economical immunopotentiator to raise the immunity and antibacterial response as a replacement for antibiotics, a recombinant yeast co-expressing pig interleukin-17 (IL-17) and IL-22 was constructed and designated as Po1h-pINA1297-IL-17/22. To evaluate the immunoregulator activities of Po1h-pINA1297-IL-17/22, two experiment groups (oral inoculation with Po1h-pINA1297 or Po1h-pINA1297-IL-17/22) and a negative control group (PBS) were set up using 4-week-old female BALB/c mice (10/group). The level of cytokines, including IL-2, IL-4, IL-10, and IFN-γ, were detected by ELISA, and the circulating CD4+ and CD8+ lymphocytes were quantified by flow cytometry. The IgG and secretory IgA (SIgA) levels in both small intestine and fecal matter were also measured by ELISA. The results indicated that the IgG antibody titer and SIgA concentration increased significantly in the Po1h-pINA1297-IL17/22 group in comparison with the controls (p < 0.05) and so did the cytokine levels in the serum (IL-2, IL-4, IL-10, and IFN-γ). In addition, CD4+ and CD8+ T cells were also obviously elevated in the Po1h-pINA1297-IL17/22 group on 35th day (p < 0.05). After challenge with pathogenic Salmonella typhimurium, the Po1h-pINA1297-IL17/22 group showed a relatively higher survival rate without obvious infectious symptoms. On the contrary, the mortality of control group reached 80% due to bacterial infection. As for the piglet experiment, 30 healthy 7-day piglets were similarly attributed into three groups. The oral inoculation of piglets with Po1h-pINA1297-IL17/22 also markedly improved the growth performance and systemic immunity (up-regulations of IL-4, IL-6, IL-15, IL-17, IL-22, and IL-23). Overall, the results indicated that Po1h-pINA1297-IL17/22 effectively promoted the humoral and cellular immunity against bacterial infection. These proved the promising potential of Po1h-pINA1297-IL-17/22 to be a potent immunopotentiator for the prevention of microbial pathogen infections.

Levels of Genetic Variants Among Symptomatic Blastocystis Subtypes and their Relationship to Mucosal Immune Surveillance in the Precancerous Colons of Experimentally Infected Rats

PurposeThe relationship between the genetic diversity of Blastocystis and immune surveillance in precancerous colons with blastocystosis is still under investigation. This study aimed to identify the genetic Blastocystis variants among 54 symptomatic human isolates and their relationship to mucosal immune surveillance in the precancerous polyps of experimentally infected rats.MethodsPolymerase chain reaction and high-resolution melting (PCR/HRM) curves discriminated human symptomatic Blastocystis isolates into subtypes (STs)/intrasubtypes, which were orally administered to rats to induce experimental infection. Then, the mucosal immune responses of the infected colons were evaluated in relation to polyp formation through immunostaining to identify mucus MUC2 and determine mucosal immune cell (goblet, lymphocyte and mast) counts, secretory IgA levels and parasitic intestinal invasion.ResultsST1, ST3, and ST4 were found in 18.5% (10/54), 54.7% (29/54), and 27.8% (15/54) of the samples, respectively. Then, the HRM curve discriminated ST3 into the wild, mutant, and heterozygous [17/54 (31.5%), 5/54 (9.3%), and 7/54 (12.9%)] intrasubtypes. ST1 and ST4 had no genetic variations. Precancerous polyps were detected in the colons of 40.5% of the infected rats. ST1 constituted 14.7% of these cases, while the wild, mutant, and heterozygous intrasubtypes of ST3 showed polyps in 12.9%, 5.5%, and 5.5% of cases, respectively. Only 1.9% of the polyps were related to ST4. MUC2 showed weak immunostaining in 44.5% of the infected colons, and 38.9% were polyp inducers. Low goblet cell numbers and high interepithelial lymphocyte counts were significantly associated with polyp formation, particularly with ST1 and wild ST3. Among the polyp inducers, high numbers of mast cells were detected in wild ST3 and ST4, while a low number was found with heterozygous ST3. The level of secretory IgA was low in polyp-inducing STs. Most of the results were statistically significant.ConclusionImmunosurveillance showed a potential relationship between ST1 and the ST3 intrasubtypes and precancerous polyps. This relationship may provide insight into the prevention and/or development of new immunotherapeutic strategies to combat colorectal cancer.

Immunogenicity of engineered probiotics expressing conserved antigens of influenza virus and FLIC flagellin against H9N2 AIVinfection in mice

Avian influenza virus (AIV)is easy to cause diseases in birds and humans.It causes great economic losses to the poultry farms and leads to public health problems. Using vaccines is the main approach to control the prevalence of AIV. In our previously published article, a recombinant Lactobacillus plantarum (L. plantarum) expressing the NP-M2 peptide ofH9N2 AIV was generated, and its protective effect was evaluated in a chicken model. In this study, the protective effect was estimated in mice model. Humoral and cellular immune response parameters were measured using flow cytometry adding to body weight loss, survival rate, virus load, and histopathological changes in the lung. The obtained results elucidated that, the recombinant L. plantarum can promote the activation of dendritic cells (DC), proliferation of T and B cells adding to eliciting protective secretory IgA (sIgA) and humeral IgG level in mice model. Accordingly, it could be used as a patent vaccine to control the AIV infection.

Laying performance, egg quality, fertility, nutrient digestibility, digestive enzymes activity, gut microbiota, intestinal morphology, antioxidant capacity, mucosal immunity, and cytokine levels in meat-type Japanese quail breeders fed different phytogenic levels

A total of 180 female Japanese quail breeders were allocated to 5 treatments with 6 replicates of 6 birds and fed a diet supplemented with 0, 125, 250, 500, or 1000 mg/kg of a phytogenic feed additive (PFA) in a 9-wk experiment. Egg weight, feed efficiency, shell breaking strength and calcium content, specific gravity, Haugh unit, and percentages of fertile eggs increased with increasing PFA levels (P < 0.05). Increasing of PFA levels increased nutrient digestibility, dietary AMEn, and activities of digestive enzymes in the pancreas and intestinal digesta (P < 0.05). Supplementation of PFA reduced Escherichia coli (P < 0.05), Clostridium spp. (P < 0.05) and Salmonella spp. counts (P < 0.05), while increased Lactobacillus and Bifidobacterium spp. counts in the ileal and cecal contents (P < 0.05). Dietary PFA increased jejunal villus height and decreased ileal crypt depth (P < 0.05). Serum diamine oxidase activity and D-lactate level were decreased with increase in PFA level (P < 0.05). Increasing PFA levels increased glutathione peroxidase activity in the pancreas, small intestine, and cecal tonsil, but decreased malondialdehyde contents (P < 0.05). Birds fed PFA exhibited increased levels of secretory IgA in the intestinal mucosa (P < 0.05), and increased the percentage of CD3+ T cells, ratio of CD4+/CD8+ T cells, and cytokine concentrations in the cecal tonsils (P < 0.05). In conclusion, PFA could improve gut health and nutrient utilization and, therefore, benefit productivity, egg quality, and fertility in quails.

Comparison of Effects of Storage at Different Temperatures in a Refrigerator, Upright Freezer on Top of Refrigerator, and Deep Freezer on the Immunoglobulin A Concentration and Lysozyme Activity of Human Milk.

This study aimed to investigate the effects of storing expressed human milk (HM) at different domestic storage temperatures on the secretory immunoglobulin A (SIgA) concentration and lysozyme activity. Forty mothers of full-term infants aged one to six months provided milk samples. The fresh samples were examined within 24 h of expression, and the other samples were stored in a refrigerator for four days or in two types of freezers for six months. The SIgA concentrations and lysozyme activity in the milk samples were studied using enzyme-linked immunosorbent assay (ELISA) kits and fluorometric lysozyme activity assay kits, respectively. The pairwise comparisons of the SIgA concentration and lysozyme activity were carried out using one-way analysis of variance with Dunnett T3 or Kruskal–Wallis tests with Bonferroni correction, depending on the data distribution. The mean temperatures of the refrigerator, upright freezer on top of the refrigerator, and deep freezer (chest freezer) were 2.0, −16.7, and −22.3 °C, respectively. Our study results highlight that the SIgA concentration and lysozyme activity of HM stored in the refrigerator for four days and in freezers for six months were significantly lower than those of fresh HM (p < 0.001). During the first six months of storage in both types of freezers, the SIgA levels were stable, whereas the lysozyme activity significantly decreased (p < 0.001). HM stored in the deep freezer had a higher SIgA concentration and lysozyme activity than HM stored in the upright freezer on top of the refrigerator. Our data support the superiority of fresh human milk over stored HM. If HM is to be stored, then storage in a deep freezer is potentially a more effective method for the preservation of SIgA concentrations and lysozyme activity than storage by refrigeration for four days or in an upright freezer on top of a refrigerator for six months.

Survival of Vaccine-Induced Human Milk SARS-CoV-2 IgG, IgA and SIgA Immunoglobulins across Simulated Human Infant Gastrointestinal Digestion.

Breastfeeding can be a vital way of acquiring passive immunity via the transfer of antibodies from the mother to the breastfeeding infant. Recent evidence points to the fact that human milk contains immunoglobulins (Ig) against the SARS-CoV-2 virus, either after natural infection or vaccination, but whether these antibodies can resist enzymatic degradation during digestion in the infant gastrointestinal (GI) tract or indeed protect the consumers remains inconclusive. Herein, we evaluated the levels of IgG, IgA, and secretory IgA (SIgA) antibodies against the spike protein of SARS-CoV-2 in 43 lactating mothers who received at least two doses of either an mRNA-based vaccine (Pfizer/BioNTech, Moderna; n = 34) or an adenovirus-based vaccine (AstraZeneca; n = 9). We also accessed the potential persistence of SARS-CoV-2 IgA, IgG, and secretory IgA (SIgA) antibodies from vaccinated women in the GI tract of the infants by means of a static in vitro digestion protocol. Our data depict that, although slightly reduced, the IgA antibodies produced after vaccination resist both the gastric and intestinal phases of infant digestion, whereas the IgGs are more prone to degradation in both phases of digestion. Additionally, SIgA antibodies were found to greatly resist the gastric phase of digestion albeit showing some reduction during the intestinal phase. The evaluation of the vaccine induced Ig profile of breastmilk, and the extent to which these antibodies can resist digestion in the infant GI tract provide important information about the potential protective role of this form of passive immunity that could help decision making during the COVID-19 pandemic and beyond.

Effects of the thawing rate and heating temperature on immunoglobulin A and lysozyme activity in human milk

BackgroundThe percentage of infants receiving frozen human milk (HM) is increasing. The effects of thawing and warming on the secretory immunoglobulin A (SIgA) level and lysozyme activity in frozen HM should be investigated to identify optimal methods for preserving immune factors in frozen HM.MethodsMilk samples were collected from 40 mothers with healthy full-term infants who had been lactating for one to six months. The baseline samples were analyzed within 24 h after collection, and the other samples were frozen at -18 °C before analyses. We compared two methods: placing the container overnight in a refrigerator at 4 °C before warming (slow thawing) and immediately thawing in warm water after removing the sample from the freezer (rapid thawing). Additionally, we investigated the effects of the warming temperature by comparing room temperature (25 °C) and physiological temperature (37 °C). The SIgA concentrations and lysozyme activities in the milk samples were determined using ELISA kits and fluorometric lysozyme activity assay kits, respectively.ResultsThe SIgA concentrations and lysozyme activity in frozen HM were 16.5–52.1% and 16.8–39.3% lower than those in fresh HM, respectively. The SIgA concentrations in frozen HM were stable during slow thawing at 37 °C (p = 0.072) compared with those in fresh HM. The SIgA concentrations and lysozyme activity were maintained at significantly higher levels during slow thawing than during rapid thawing at 25 °C (p = 0.002 and p < 0.001, respectively). Slow thawing preserved higher SIgA concentrations and lysozyme activity than rapid thawing at 37 °C, but the difference was not significant.ConclusionsThe SIgA level in HM frozen at -18 °C for two months was stable after overnight thawing in the refrigerator (4 °C for 12 h) before warming to 37 °C compared with that in fresh milk. The thawing of HM in the refrigerator overnight (and then warming to 25 °C or 37 °C for 30 min) has the potential to preserve the SIgA concentration and lysozyme activity to a greater extent than heating immediately after removal from the freezer. Broader temperature ranges should be analyzed to determine the temperature that minimizes the losses in SIgA concentration and lysozyme activity in HM.

DYNAMICS OF SIgA CONTENT IN BREAST MILK WHEN RISK FACTORS AND LACTATIONAL CHARACTERISTICS ARE CONSIDERED

The leading role associated with an anti-infective action of breast milk belongs to secretory IgA (SIgA). Therefore, the determination of the level of SIgA in colostrum and milk of mothers with different lactation levels and mothers at risk at different levels and duration of lactation has a practical interest.&#x0D; Aim. The research aims at studying the dynamics of SIgA content in breast milk, taking into account risk factors and features of lactation.&#x0D; Material and Methods. The content of SIgA in colostrum and breast milk of 372 mothers with full lactation and 208 with hypogalactia, of which 72 with early and 146 with late hypogalactia at different times of lactation (1-8 days and 1-3 months) was determined. The SIgA content was also studied in mothers; 65 with preeclampsia, including 12 with early hypogalactia, 24 with late hypogalactia, 23 with full lactation, and 44 with anemia of pregnancy, including 12 with early hypogalactia, 19 with late hypogalactia and 13 with full lactation. The determination of SIgA content in colostrum and milk was performed using the method of simple radial immunodiffusion in a gel by G. Mancini et al.&#x0D; Results and Discussion. The SIgA concentration in colostrum and breast milk decreased during the secretion process. In early hypogalactia, the content of SIgA did not differ significantly from the level of SIgA in colostrum and breast milk with full lactation in the early neonatal period and at 1-3 months of secretion. In the late hypogalactia, SIgA content did not differ significantly from its level in the control group. Due to the lower amount of milk received by the mother's child with hypogalactia, the supply of children with SIgA is insufficient, and the deficit is higher the sooner the hypogalactia develops. Similar changes in the dynamics of SIgA content have been found in mothers with preeclampsia and at different levels of lactation. The exception was the content of SIgA in colostrum and milk of mothers with anemia of pregnancy and early hypogalactia, which in the first five days of lactation was lower than in mothers with full lactation.&#x0D; Conclusion. The SIgA concentration in colostrum and breast milk decreases during the secretion process. The level of lactation does not affect the dynamics of SIgA content, except for the SIgA content in colostrum and breast milk of mothers with anemia of pregnancy and hypogalactia in the early stages of secretion. Despite the absence of a significant difference in SIgA levels in mothers with different levels of lactation due to less colostrum and milk received by children with early and late hypogalactia, the supply of SIgA is insufficient, and the cumulative deficit is higher the faster the hypogalactia develops.

Intestinal Immune Development Is Accompanied by Temporal Deviation in Microbiota Composition of Newly Hatched Pigeon Squabs.

ABSTRACTIdentifying the interaction between intestinal mucosal immune system development and commensal microbiota colonization in neonates is of paramount importance for understanding how early life events affect resistance to disease later in life. However, knowledge about this interaction during the early posthatch development period in altrices is limited. To fill this gap, samples of intestinal content and tissue were collected from newly hatched pigeon squabs at four time points (days 0, 7, 14, and 21) for microbial community analysis and genome-wide transcriptome profiling, respectively. We show that the first week after hatching seems to be the critical window for ileal microbiota colonization and that a potentially stable microbiota has not yet been well established at 21 days of age. Regional transcriptome differences revealed that the jejunum rather than the ileum plays a crucial role in immunity at both the innate and adaptive levels. In the ileum, temporal deviation in innate immune-related genes mainly occurs in the first week of life and is accompanied by a temporal change in microbiota composition, indicating that the ileal innate mucosal immune system development regulated by microbial colonization occurs mainly in this period. Furthermore, we provide evidence that colonization by Escherichia and Lactobacillus within the first week of life is likely one of the causative factors for the induction of proinflammatory cytokine expression in the ileum. We also demonstrate that cellular adaptive immune responses mediated by Th17 cells following commensal-induced proinflammatory cytokine production in the ileum begin as early as the first week posthatch, but this cellular immunity seems to be less effective in terms of maintaining the inflammatory response balance. Because the induction of high levels of mucosal secretory IgA (SIgA) seems to take approximately 3 weeks, we favor the idea that humoral adaptive immunity might be less active, at least, during the first 2 weeks of life. Our data may help to explain the phenomenon of the occurrence of intestinal infections mainly in the ileum of pigeon squabs during the early posthatch period.IMPORTANCE The pigeon (Columba livia), an altricial bird, is one of the most economically important farmed poultry for table purposes. Identifying the interaction between intestinal mucosal immune system development and commensal microbiota colonization in neonates is of paramount importance for understanding how early life events affect resistance to disease and potential productivity later in life. However, knowledge about this interaction during the early posthatch development period in altricial birds is limited. The study described herein is the first to try to provide insights into this interaction. Our data provide evidence on the mutual relationship between intestinal mucosal immune system development and commensal microbiota colonization in pigeon squabs and may help to explain the phenomenon of the occurrence of intestinal infections mainly in the ileum of pigeon squabs during the early posthatch period.

Oral Immunization of Chickens with Probiotic Lactobacillus crispatus Constitutively Expressing the α-β2-ε-β1 Toxoids to Induce Protective Immunity.

Clostridium perfringens (C. perfringens) is a bacterium that commonly causes zoonotic disease. The pathogenicity of C. perfringens is a result of the combined action of α, β, and ε exotoxins. In this study, Lactobacillus crispatus (pPG-T7g10/L. crispatus) expressing the main toxoids of C. perfringens, α, ε, β1, and β2, with EGFP-labeling, was constructed, and the protective effect was estimated in chickens. The α-β2-ε-β1 toxoid was constitutively expressed for confirmation by laser confocal microscopy and western blotting, and its immunogenicity was analyzed by enzyme-linked immunosorbent assay (ELISA) and immunohistochemical assays. After booster immunization, the probiotic vaccine group showed significantly higher levels (p < 0.05) of specific secretory IgA (sIgA) and IgY antibodies in the serum and intestinal mucus. Furthermore, the levels of cytokines, including interferon (IFN)-γ, interleukin (lL)-2, IL-4, IL-10, IL-12, and IL-17, and the proliferation of spleen lymphocytes in chickens orally immunized with pPG-E-α-β2-ε-β1/L. crispatus increased significantly. Histopathological observations showed that the intestinal pathological changes in chickens immunized with pPG-E-α-β2ε-β1/L. crispatus were significantly alleviated. These data reveal that the probiotic vaccine could stimulate mucosal, cellular, and humoral immunity and provide an active defense against the toxins of C. perfringens, suggesting a promising candidate for oral vaccines against C. perfringens.

Beneficial Alteration in Growth Performance, Immune Status, and Intestinal Microbiota by Supplementation of Activated Charcoal-Herb Extractum Complex in Broilers.

This study aimed to examine the effects of activated charcoal-herb extractum complex (CHC) on the growth performance of broilers, inflammatory status, microbiota, and their relationships. A total of 864 1-day-old Arbor Acres male broilers (41.83 ± 0.64 g) were distributed to eight dietary treatments with six replicates (18 birds per replicate), which were a corn-soybean meal-based diet (NCON); basal diets supplemented with 250, 500, 750, or 1,000 mg/kg CHC, and three positive controls; basal diets supplemented with 200 mg/kg antibacterial peptide (AMP), 200 mg/kg calsporin (Probio) or 500 mg/kg montmorillonite. The study period was 42 days including the starter (day 0–21) and grower (day 22–42) phases. Compared with the NCON group, CHC supplementation (optimal dose of 500 mg/kg) increased (p < 0.05) growth performance and tended to increase feed conversion rate in broilers. CHC (optimal dose of 500 mg/kg) decreased the level of the interleukin-1β (IL-1β) and interferon-γ (IFN-γ) in serum and improved the levels of immunoglobulins A (IgA) and immunoglobulins A (IgM) in serum, and secretory immunoglobulin A (SIgA) in the mucosa of duodenum and jejunum (p < 0.05). In the ileum, CHC supplementation decreased community abundance represented by lower Sobs, Chao 1, Ace, and Shannon compared with NCON (p < 0.05). At the phylum level, CHC supplementation increased the abundance of Firmicutes, while decreasing the abundance of Bacteroidetes in ileum and cecum (p < 0.05). At the genus level, compared with the NCON group, CHC markedly reduced (p < 0.05) the abundances of pathogenic bacteria Alistipes in the ileum, which were negatively associated with the levels of SIgA and IL-1β in ileum mucosa. In conclusion, CHC had beneficial effects on growth performance, immune status, and intestinal microbiota composition. CHC had dual functions of absorption like clays and antibacterial like antibacterial peptides.

Extramucosal Formation and Prognostic Value of Secretory Antibodies in Rheumatoid Arthritis.

To investigate levels and possible extramucosal formation of secretory Ig, including anti-citrullinated protein antibodies (ACPAs), in rheumatoid arthritis (RA). Three patient groups were studied: 1) ACPA-positive patients with musculoskeletal pain without clinical arthritis, 2) patients with recent-onset RA, and 3) patients with established RA. In baseline serum samples (groups 1 and 2) and paired synovial fluid samples (group 3), we analyzed total secretory IgA, total secretory IgM, free secretory component (SC), and SC-containing ACPA. Extramucosal formation of SC-containing ACPA was investigated by preincubating RA sera and affinity-purified ACPA with recombinant free SC. Compared to healthy controls, serum levels of total secretory IgA and total secretory IgM were increased both in patients with early RA and at-risk patients (P < 0.05). Patients with early RA with elevated total secretory Ig had significantly higher disease activity during the 3-year follow-up period compared to those without increased levels. At-risk patients who developed arthritis during follow-up (39 of 82) had higher baseline total secretory IgA levels compared to those who did not (P = 0.041). In established RA, total secretory IgA and total secretory IgM levels were higher in serum than in synovial fluid (P < 0.0001), but SC-containing ACPAs adjusted for total secretory Ig concentration were higher in synovial fluid (P < 0.0001). Preincubation with recombinant free SC yielded increased SC-containing ACPA reactivity in sera as well as in affinity-purified IgA and IgM ACPA preparations. Circulating secretory Ig are elevated before and at RA onset. In the presence of free SC, secretory Ig may form outside the mucosa, and SC-containing ACPAs are enriched in RA joints. These findings shed important new light on the mucosal connection in RA development.