Ileal Peyer's Patches Research Articles

Diurnal changes in bacterial settlement on the Peyer's patch and surrounding mucosa in the rat ileum and its effect against the intestinal immune system.

Our previous study revealed the diurnal change in the indigenous bacteria settling on the terminal region of the rat ileum. In the present study, we investigated the diurnal change in indigenous bacteria on the most distal ileal Peyer's patch (PP) and surrounding ileal mucosa and explored how stimulation from indigenous bacteria for a day affects the intestinal immune system at the beginning of the light phase. Histological measurement revealed that bacteria adjacent to the follicle-associated epithelium of PP and to the villous epithelium of the surrounding ileal mucosa are more abundant at zeitgeber time (ZT)0 and ZT18 than at ZT12. On the other hand, tissue-section 16S rRNA amplicon sequencing revealed no significant difference between ZT0 and ZT12 in the bacterial composition on the ileal tissue including the PP. One-day treatment with an antibiotic (Abx) successfully impaired the settlement of bacteria around the ileal PP. In transcriptome analysis, 1-day Abx treatment led to the downregulation of several chemokines in both PP and ordinary ileal mucosa at ZT0. Histological analysis of the 1-day Abx group revealed decreases in both CD68+ macrophages in PP and naphthol AS-D chloroacetate esterase stain-positive mast cells in the ileal villi. Together, these findings suggest that the colonies of indigenous bacteria on the distal ileal PP and surrounding mucosa expand during the dark phase, which might lead to the expression of genes to regulate the intestinal immune system and contribute to the homeostasis of at least macrophages in PP and mast cells in the ileal mucosa.

Commensal microbiota modulates phenotypic characteristics and gene expression in piglet Peyer's patches.

The gastrointestinal tract contains a complex microbial community. Peyer's patches (PPs) play an important role in inducing mucosal immune responses in the gastrointestinal tract. However, little is known about the effect of commensal microbiota on the host's PPs. Here, we analyzed the phenotypic-to-transcriptome changes in the intestine PPs of specific pathogen-free (SPF) and germ-free (GF) piglets (fed in an environment with and without commensal microbiota, respectively) to elucidate the role of commensal microbiota in host intestine mucosal immunity. Analyses of anatomical and histological characteristics showed that commensal microbiota deficiency led to PP hypoplasia, especially regarding B and T cells. A total of 12,444 mRNAs were expressed in 12 libraries; 2,156 and 425 differentially expressed (DE) mRNAs were detected in the jejunal PP (JPP) and ileal PP (IPP), respectively (SPF vs. GF). The shared DE mRNAs of the JPP and IPP were mainly involved in basic physiological and metabolic processes, while the specific DE mRNAs were enriched in regulating immune cells in the JPP and microbial responses and cellular immunity in the IPP. Commensal microbiota significantly modulated the expression of genes related to B-cell functions, including activation, proliferation, differentiation, apoptosis, receptor signaling, germinal center formation, and IgA isotype class switching, particularly in the JPP. TLR4 pathway-related genes were induced in response to microbial colonization and in LPS/SCFA-treated B cells. We also detected 69 and 21 DE lncRNAs in the JPP and IPP, respectively, and four one-to-one lncRNA-mRNA pairs were identified. These findings might represent key regulatory axes for host intestine mucosal immunity development during microbial colonization. Overall, the findings of this study revealed that commensal microbiota modulated phenotypic characteristics and gene expression in the piglet intestine PPs and underscored the importance of early microbial colonization for host mucosal immunity development.

Limosilactobacillus reuteri FN041 prevents atopic dermatitis in pup mice by remodeling the ileal microbiota and regulating gene expression in Peyer's patches after vertical transmission.

ObjectivesLimosilactobacillus reuteri FN041 is a potential probiotic bacterium isolated from breast milk in traditional farming and pastoral areas of China. The purpose of this study was to investigate the optimal intervention mode and potential mechanism of FN041 to prevent atopic dermatitis (AD) in mice.MethodsIn intervention mode I, FN041 was supplemented to dams during the late trimester and lactation and pups after weaning; in intervention mode II, FN041 was supplemented after pups were weaned. AD was induced in pups with MC903 plus ovalbumin on the ear after weaning.ResultsThe effect of intervention mode I in preventing AD was significantly better than that of intervention mode II. Compared with the model group, the inflammatory response of the pup’s ears, the proportion of spleen regulatory T cells and the plasma IgE were significantly decreased in mice in intervention mode I. Furthermore, the intestinal mucosal barrier was enhanced, and the Shannon index of the ileal microbiota was significantly increased. The microbiota structure deviated from the AD controls and shifted toward the healthy controls according to the PCoA of unweighted UniFrac. The relative abundances of Limosilactobacillus, Faecalibacterium, Bifidobacterium, and Akkermansia in the ileum were significantly increased compared to the AD group. Based on RNA-seq analysis of pups’ Peyer’s patches (PPs), FN041 inhibits autoimmune pathways such as asthma and systemic lupus erythematosus and activates retinol metabolism and PPAR signaling pathways to reduce inflammatory responses. Intervention mode II also significantly reduced AD severity score, but the reduction was approximately 67% of that of intervention mode I. This may be related to its ineffective remodeling of the ileal microbiota.ConclusionPrenatal and postnatal administration of FN041 is an effective way to prevent AD in offspring, and its mechanism is related to remodeling of ileal microbiota and PPs immune response.

No evidence of uptake or propagation of reindeer CWD prions in environmentally exposed sheep

BackgroundChronic wasting disease (CWD) is a prion disease of cervids first reported in North America in the 1960s. In Europe, CWD was first diagnosed in 2016 in a wild reindeer in Norway. Detection of two more cases in the same mountain area led to the complete culling of this partially confined reindeer population of about 2400 animals. A total of 19 CWD positive animals were identified. The affected area is extensively used for the grazing of sheep during summers. There are many mineral licks intended for sheep in the area, but these have also been used by reindeer. This overlap in area use raised concerns for cross-species prion transmission between reindeer and sheep. In this study, we have used global positioning system (GPS) data from sheep and reindeer, including tracking one of the CWD positive reindeer, to investigate spatial and time-relevant overlaps between these two species. Since prions can accumulate in lymphoid follicles following oral uptake, samples of gut-associated lymphoid tissue (GALT) from 425 lambs and 78 adult sheep, which had grazed in the region during the relevant timeframe, were analyzed for the presence of prions. The recto-anal mucosa associated lymphoid tissue (RAMALT) from all the animals were examined by histology, immunohistochemistry (IHC) and enzyme-linked immunosorbent assay (ELISA), and the ileal Peyer's patch (IPP) from a subsample of 37 lambs were examined by histology and IHC, for the detection of prions.ResultsGPS data showed an overlap in area use between the infected reindeer herd and the sheep. In addition, the GPS positions of an infected reindeer and some of the sampled sheep showed temporospatial overlap. No prions were detected in the GALT of the investigated sheep even though the mean lymphoid follicle number in RAMALT and IPP samples were high.ConclusionThe absence of prions in the GALT of sheep that have shared pasture with CWD-infected reindeer, may suggest that transmission of this novel CWD strain to sheep does not easily occur under the conditions found in these mountains. We document that the lymphoid follicle rich RAMALT could be a useful tool to screen for prions in sheep.

Disrupted Peyer's Patch Microanatomy in COVID-19 Including Germinal Centre Atrophy Independent of Local Virus.

Confirmed SARS-coronavirus-2 infection with gastrointestinal symptoms and changes in microbiota associated with coronavirus disease 2019 (COVID-19) severity have been previously reported, but the disease impact on the architecture and cellularity of ileal Peyer’s patches (PP) remains unknown. Here we analysed post-mortem tissues from throughout the gastrointestinal (GI) tract of patients who died with COVID-19. When virus was detected by PCR in the GI tract, immunohistochemistry identified virus in epithelium and lamina propria macrophages, but not in lymphoid tissues. Immunohistochemistry and imaging mass cytometry (IMC) analysis of ileal PP revealed depletion of germinal centres (GC), disruption of B cell/T cell zonation and decreased potential B and T cell interaction and lower nuclear density in COVID-19 patients. This occurred independent of the local viral levels. The changes in PP demonstrate that the ability to mount an intestinal immune response is compromised in severe COVID-19, which could contribute to observed dysbiosis.

Organogenesis of Ileal Peyer's Patches Is Initiated Prenatally and Accelerated Postnatally With Comprehensive Proliferation of B Cells in Pigs

Morphogenesis and differentiation of organs is required for subsequent functional maturation. The morphological features of Peyer's patches vary among species. In pigs, they develop extensively in the ileum as ileal Peyer's patches (IPPs). However, the role of IPPs in the porcine immune system remains to be elucidated because of a lack of complete understanding of IPP organogenesis. Results of the present study revealed that development of porcine IPPs is initiated prenatally between embryonic days 76 and 91. The process of IPP organogenesis is concomitant with increased transcriptional patterns of CXCL13 and CCL19. IPPs undergo further development postnatally by forming central, marginal, and subepithelial zones. Importantly, a large number of proliferating B cells and apoptotic cells are found in porcine IPPs postnatally, but not prenatally. The expression level of IgM in proliferating B cells depends on the zone in which distinct B cells are separately localized after birth. Specifically, IgM+ cells are predominantly found in the central zone, whereas IgM-/low cells are abundant in the marginal zone. Importantly, the cellular feature of IPPs differs from that of mesenteric lymph nodes (MLNs) where such distinct zones are not formed both prenatally and postnatally. Our findings suggest that IPPs (not MLNs) in postnatal pigs are involved in complementing functions of the primary lymphoid tissue that promotes the differentiation and maturation of B cells.

Dietary Mannan Oligosaccharides Modulate Gut Inflammatory Response and Improve Duodenal Villi Height in Post-Weaning Piglets Improving Feed Efficiency.

The aim of this study was to evaluate the effects of mannan oligosaccharides (MOS) on gut health and performance in post-weaning piglets. In total, 40 piglets were divided into two experimental groups and fed a basal diet with (TRT) or without (CON) 0.2% mannan oligosaccharides for 35 days. Growth performance was determined weekly and faecal microbial composition on days 0, 14 and 35. On day 36, histometrical evaluations were performed on duodenal, jejunal, ileal, and colon samples. mRNA gene expression of inflammation-related genes was evaluated in samples of ileal Peyer's patches (IPP). MOS administration improved feed efficiency in the last two weeks of the trial (p < 0.05), and a decreased clostridia content was found in faeces at day 14 (p = 0.05). TRT piglets showed increased duodenal villi height (p < 0.05), and reduced mRNA levels of Tumour Necrosis Factor α (p < 0.05) and Toll-Like Receptor 4 (p < 0.01) in IPP. Our results suggest beneficial effects of MOS supplementation on gut morphology and the expression of inflammation-related genes in post-weaning piglets, accompanied by increased feed efficiency.

Regional Dichotomy in Enteric Mucosal Immune Responses to a Persistent Mycobacterium avium ssp. paratuberculosis Infection.

Chronic enteric Mycobacterium avium ssp. paratuberculosis (MAP) infections are endemic in ruminants globally resulting in significant production losses. The mucosal immune responses occurring at the site of infection, specifically in Peyer's patches (PP), are not well-understood. The ruminant small intestine possesses two functionally distinct PPs. Discrete PPs function as mucosal immune induction sites and a single continuous PP, in the terminal small intestine, functions as a primary lymphoid tissue for B cell repertoire diversification. We investigated whether MAP infection of discrete vs. continuous PPs resulted in the induction of significantly different pathogen-specific immune responses and persistence of MAP infection. Surgically isolated intestinal segments in neonatal calves were used to target MAP infection to individual PPs. At 12 months post-infection, MAP persisted in continuous PP (n = 4), but was significantly reduced (p = 0.046) in discrete PP (n = 5). RNA-seq analysis revealed control of MAP infection in discrete PP was associated with extensive transcriptomic changes (1,707 differentially expressed genes) but MAP persistent in continuous PP elicited few host responses (4 differentially expressed genes). Cytokine gene expression in tissue and MAP-specific recall responses by mucosal immune cells isolated from PP, lamina propria and mesenteric lymph node revealed interleukin (IL)22 and IL27 as unique correlates of protection associated with decreased MAP infection in discrete PP. This study provides the first description of mucosal immune responses occurring in bovine discrete jejunal PPs and reveals that a significant reduction in MAP infection is associated with specific cytokine responses. Conversely, MAP infection persists in the continuous ileal PP with minimal perturbation of host immune responses. These data reveal a marked dichotomy in host-MAP interactions within the two functionally distinct PPs of the small intestine and identifies mucosal immune responses associated with the control of a mycobacterial infection in the natural host.

Sensitivity of Mouse Small Intestinal Immune Tissue Architecture

The different regions of the small intestinal lymphoid tissues may have developed a different immuno‐cytohistological structures with a different sensitivity in response to different intralumenal contents. However, the distribution and density of immune cell subsets, lymphatics, and their spatiotemporal relationship within or among Peyer’s Patches (PP), the major lymphoid immune tissues from proximal to distal ends of the small intestine, have not been clearly documented. The jejunal (Jej), mid‐segmental (Mid, Btw. Jej &amp; Ile), and ileal (Ile) PPs in C57BL/6 mice were isolated, frozen‐sectioned, and immunohistochemistrico‐stained for the imaging analysis and comparison on the distribution, density, area, and size of immune cells, lymphatics, and their spatiotemporal relations between the peripheral and interfollicular regions within or among the different PPs.Results1. Density of CD4+cells in the interfollicular regions (IFR) were significantly higher than those in the peripheral regions (PR) within each PP. 2. Total density of CD4+ or MHCII+ cells in MidPP were significantly higher than those in the JejPP. 3. The total density of CD8+cells in MidPP or CD68+cells in IlePP were significantly higher than those in the JejPP. 4. Total lymphatic area, density, or size in MidPP were significantly larger than those in JejPP. 5. Lymphatic area in IFR of MidPP or its density in IFR of MidPPs or IlePPs were significantly larger than those in the PR of the corresponding PPs. 6. Branched villi‐lacteals &amp; their subsequent submucous lymphatic network wrapped by a higher density of CD4+ &amp; MHCII+ cells directly form a specialized histo‐architecture, branched villi‐Lv‐PP complex for immune recognition/differentiation in mouse small intestine. The histo‐morphological architectures of mouse small intestinal immune tissues infrastructure its sensitivity as an immune‐surveillance sensor, facilitating its sensibility. This study provides a necessary foundation for understanding immune‐related intestinal dysfunctions and diseases.

The role of diet‐induced obesity on Peyer's Patch gene expression

Peyer’s Patches (PP) are part of the complex gut‐associated lymphoid tissue located throughout the intestinal wall. PP consists of highly organized ovoid‐shaped follicles, classified as non‐encapsulated lymphatic tissues. PP are populated with B cells, T cells, macrophages and dendritic cells allowing them to function as an organism’s internal surveillance of the intestine. There is limited research on PP in relation to diet‐induced obesity. In the current study, we attempt to close this gap in knowledge. We placed male, Long Evans rats on Chow or high‐fat diet (HFD) for 8 weeks and harvested PP from the small intestine. HFD‐fed rats had significantly increased number of total PP, p&lt;0.05. All rats had significantly reduced number of PP in the duodenum in comparison to either the jejunum or ileum, p&lt;0.0001. We performed gene expression analysis for immune cell markers in mRNA obtained from individual PP in the 3 distinct regions of the intestine. Expression of T cell markers CD4/CD3 was differentially reduced in PP from the distal intestine in comparison to the proximal. Macrophage marker, CD68, was more highly expressed in the duodenum in comparison to the more distal PP. Master regulator of T cell expression, TGFβ, is more highly expressed in duodenal PP in comparison to ileal PP, p&lt;0.05. In summary, gene expression of immune cell markers was most highly associated with the location of the intestinal PP. Surprisingly, HFD did not influence gene expression of immune markers in the PP as was predicted. Further work is necessary to understand whether other inflammatory markers are affected by obesity.

Oral Deliverable Mucoadhesive Chitosan-Salmonella Subunit Nanovaccine for Layer Chickens.

PurposeSalmonellosis in poultry is a serious economic burden. A major concern is the public health hazard caused by consumption of Salmonella-contaminated poultry products. Currently used Salmonella vaccines are ineffective in combating poultry Salmonellosis warranting the need of a potent vaccine, especially an oral vaccine that can elicit robust local intestinal immunity.Materials and MethodsA Salmonella subunit chitosan nanoparticles (NPs)-based vaccine was prepared that contained immunogenic outer membrane proteins (OMPs) and -flagellin (F) protein (OMPs-F-CS NPs). OMPs-F-CS NPs were administered as an oral vaccine in layer chickens and the resultant humoral and cell-mediated immune responses and localization of NPs were examined using standard detection methods.ResultsWe demonstrated targeting of surface F-protein coated chitosan NPs to immune cells when delivered orally to layer chickens, the particles were localized in ileal Peyer’s patches. The OMPs-F-CS NPs vaccinated layer chickens had significantly higher OMPs-specific mucosal IgA production and lymphocyte proliferation response. The candidate vaccine increased the expression of toll-like receptor (TLR)-2, TLR-4, IFN-γ, TGF-ß and IL-4 mRNA expression in chicken cecal tonsils.ConclusionOur study demonstrated that the chitosan-based oral Salmonella nanovaccine targets immune cells of chickens and induced antigen-specific B and T cell responses. This candidate oral Salmonella nanovaccine has the potential to mitigate Salmonellosis in poultry.

Oral supplementation of Bifidobacterium longum strain BR-108 alters cecal microbiota by stimulating gut immune system in mice irrespectively of viability.

Effect on cecal microbiota and gene expression of various cytokines in ileal Peyer's patches and cecal tissues were compared between viable and heat-killed Bifidobacterium longum strain BR-108 (BR-108) using a mouse model. Irrespectively of viability, oral supplementation of BR-108 altered the cecal microbiota and stimulated gene expression of cytokines such as IL-6 and IL-10 in ileal Peyer's patches and cecal tissue of mice. In addition, BR-108 supplementation significantly affected the relative abundance of bacterial genera and family, Oscillospira, Bacteroides and S24-7. The abundance of these bacterial genera and family strongly correlated with gene expression induced by BR-108. This study demonstrated that the effect of heat-killed BR-108 on the mouse cecal microbiota is similar to that of viable BR-108, most likely due to stimulation of the gut immune system by both heat-killed and viable BR-108 is also similar.

Immunome differences between porcine ileal and jejunal Peyer\u2019s patches revealed by global transcriptome sequencing of gut-associated lymphoid tissues

The epithelium of the intestinal mucosa and the gut-associated lymphoid tissues (GALT) constitute an essential physical and immunological barrier against pathogens. In order to study the specificities of the GALT transcriptome in pigs, we compared the transcriptome profiles of jejunal and ileal Peyer’s patches (PPs), mesenteric lymph nodes (MLNs) and peripheral blood (PB) of four male piglets by RNA-Seq. We identified 1,103 differentially expressed (DE) genes between ileal PPs (IPPs) and jejunal PPs (JPPs), and six times more DE genes between PPs and MLNs. The master regulator genes FOXP3, GATA3, STAT4, TBX21 and RORC were less expressed in IPPs compared to JPPs, whereas the transcription factor BCL6 was found more expressed in IPPs. In comparison between IPPs and JPPs, our analyses revealed predominant differential expression related to the differentiation of T cells into Th1, Th2, Th17 and iTreg in JPPs. Our results were consistent with previous reports regarding a higher T/B cells ratio in JPPs compared to IPPs. We found antisense transcription for respectively 24%, 22% and 14% of the transcripts detected in MLNs, PPs and PB, and significant positive correlations between PB and GALT transcriptomes. Allele-specific expression analyses revealed both shared and tissue-specific cis-genetic control of gene expression.

Neuropeptides and lymphocyte populations in the porcine ileum and ileocecal lymph nodes during postnatal life.

The maturation-related changes in the concentrations of galanin (Gal), vasoactive intestinal polypeptide (VIP), substance P (SP) and somatostatin (Som), as well as in subpopulations of lymphocytes expressing antigens CD2 (lymphocytes T), CD4 (T helper), CD8 (T cytotoxic), CD21 (B lymphocytes), CD5-/CD8+ (NK cells) and TCRgamma/delta (gut mucosal/intraepitelial cells) were studied in the ileal Peyer’s patches and ileo-cecal lymph nodes in female pigs aged 3 days, 2 weeks, 4 weeks and 4 months. As regards neuropeptide concentrations statistically significant changes in the ileum and lymph nodes were found only in case of Gal and VIP. The concentrations of neuropeptides were significantly higher only in new-born animals. As regards the changes in subpopulations of lymphocytes, statistically significant changes were noticed only in 4-months old animals and were dealing only with CD2+ and TCRgamma/delta cells in the ileum as well as CD4+, CD8+, CD21+ and TCRgamma/delta in lymph nodes. The highest number of CD8+, CD21+ and TCRgamma/delta lymphocytes occurred in 4-months old animals.

Engineering of Targeted Mucoadhesive Chitosan Based Salmonella Nanovaccine for Oral Delivery in Poultry

Abstract Salmonellosis in poultry is a serious economic burden. The major concern is the public health hazard by consumption of salmonella contaminated poultry meat and egg. Currently used salmonella vaccines are ineffective in combating the Salmonellosis of chicken thus warranting the need of a potent vaccine, especially an oral vaccine that can elicit robust local intestinal immunity. Biodegradable and biocompatible natural polymers are FDA approved vehicles for vaccine delivery. We prepared a candidate subunit chitosan nanoparticle vaccine containing the immunogenic outer membrane proteins (OMPs) and flagellar (F) protein of salmonella, and surface decorated with F-protein (OMPs-F-CS NPs). Physicochemical and biocompatibility properties of OMPs-F-CS NPs were studied in detail including its stability in stomach pH conditions. Salmonella targets the microfold (M) cells in the ileum Peyer’s patches (PPs) of chicken. We designed the oral OMPs-F-CS NPs vaccine to target ileal PPs to induce specific local intestinal immunity, and demonstrated that by ex vivo and in vivo studies. Layer chickens vaccinated orally with OMPs-F-CS NPs had significantly higher OMPs- specific intestinal mucosal antibody and OMPs-specific lymphocytes proliferation responses. Further, OMPs-F-CS NPs vaccination upregulated the expression of toll-like receptor (TLR) -2, TLR-4, IFN-g, IL-4 and GATA-3 mRNA levels in cecal tonsils of birds. In conclusion, we engineered chitosan based oral salmonella nanovaccine targeting intestinal PPs immune cells of birds, and demonstrated its ability to induce antigen specific mucosal antibody and T cell responses. Thus, our candidate oral salmonella vaccine has the potential to mitigate Salmonellosis in poultry.

Supplementing the feeds of layer pullets, at different ages with two different fiber sources improves immune function

Two experiments were conducted to study the effects of lignocellulose supplementation on immune function in layer pullets at different stages of growth. Four-wk-old pullets (Experiment 1) were fed a control, diet (Diet C); Diet C plus 1% mixed soluble/insoluble fiber (Diet MF), or plus 1% insoluble fiber (Diet IF). At 7.5 wk-of-age, heterophil phagocytosis, and oxidative burst in Groups MF (328.5 beads/100 cells; 4,330.0 ΔRFU; relative fluorescent units) and IF (350.3; 5,264.4) were greater (P < 0.05) than Controls (303.4; 3,509.0). At 8 wk-of-age, Group MF and IF relative weights of bursa of Fabricius (0.57 g/100 g BW; 0.58 g /100 g BW), thymus glands (0.77; 0.78), and areas of Peyer’s patches (PP) (2.7 cm2; 2.9 cm2) were higher (P < 0.05) than Controls (bursa, 0.50 g; thymus, 0.70 g; PP area, 1.8 cm2). In Experiment 2, 10-wk-old pullets were fed a control diet or diets containing 1.5% MF or IF for 8 wk. At 14 wk-of-age IF pullets had higher (P < 0.05) heterophil phagocytosis efficiency (447.9 beads/100 cells) than Controls (376.4) and MF and IF had greater (P < 0.05) oxidative burst (1,302.9 and 1,857.7 ΔRFU) than Controls (744.1). At 17 wk-of-age MF and IF had increased (P < 0.05) proliferation of T-lymphocytes (ConcanavalinA-stimulated) (100.4 and 103.1% of unstimulated cells) and B-lymphocytes (lipopolysaccharide-stimulated) (122.4 and 129.0) than Controls (ConA, 79.4; lipopolysaccharide, 106.6). At 18 wk-of-age, IF pullets were heavier (1,607.5 g, P < 0.05) than Controls (1,506.5 g), had heavier (P < 0.05) bursa of Fabricius (1.12 g) than MF and Control groups (0.98 g; 0.92 g) and cecal tonsils of MF (0.38 g) and IF (0.39 g) weighted more (P < 0.05) than Controls (0.33 g). Number of jejunal and ileal PP (10.0) in IF pullets was higher (P < 0.05) than Controls (7.1). These results indicate that both MF and IF can improve development of the immune system of young and grower pullets during periods of maturation and involution of lymphoid organs.

Microbiota-derived butyrate suppresses group 3 innate lymphoid cells in terminal ileal Peyer\u2019s patches

The regional specialization of intestinal immune cells is affected by the longitudinal heterogeneity of environmental factors. Although the distribution of group 3 innate lymphoid cells (ILC3s) is well characterized in the lamina propria, it is poorly defined in Peyer’s patches (PPs) along the intestine. Given that PP ILC3s are closely associated with mucosal immune regulation, it is important to characterize the regulatory mechanism of ILC3s. Here, we found that terminal ileal PPs of specific pathogen-free (SPF) mice have fewer NKp46+ ILC3s than jejunal PPs, while there was no difference in NKp46+ ILC3 numbers between terminal ileal and jejunal PPs in antibiotics (ABX)-treated mice. We also found that butyrate levels in the terminal ileal PPs of SPF mice were higher than those in the jejunal PPs of SPF mice and terminal ileal PPs of ABX-treated mice. The reduced number of NKp46+ ILC3s in terminal ileal PPs resulted in a decrease in Csf2 expression and, in turn, resulted in reduced regulatory T cells and enhanced antigen-specific T-cell proliferation. Thus, we suggest that NKp46+ ILC3s are negatively regulated by microbiota-derived butyrate in terminal ileal PPs and the reduced ILC3 frequency is closely associated with antigen-specific immune induction in terminal ileal PPs.

Dietary Human Milk Oligosaccharides but Not Prebiotic Oligosaccharides Increase Circulating Natural Killer Cell and Mesenteric Lymph Node Memory T Cell Populations in Noninfected and Rotavirus-Infected Neonatal Piglets

Background: Human milk oligosaccharides (HMOs) have antimicrobial and immunomodulatory actions. It has previously been reported that these oligosaccharides contribute to the reduced duration of rotavirus-induced diarrhea in pigs.Objective: We measured the effects of HMOs and prebiotic oligosaccharides on immune cell populations from noninfected and rotavirus-infected pigs. We hypothesized that dietary HMOs would modulate systemic and gastrointestinal immunity.Methods: Colostrum-deprived newborn pigs were fed formula, formula with 4 g HMOs/L (2'-fucosyllactose, lacto-N-neotetraose, 6'-sialyllactose, 3'-sialyllactose, and free sialic acid), or formula with 3.6 g short-chain galactooligosaccharides/L and 0.4 g long-chain fructooligosaccharides/L. On day 10, half of the pigs were infected with the porcine rotavirus strain OSU. Peripheral blood mononuclear cell (PBMC), mesenteric lymph node (MLN), and ileal Peyer's patch immune cell populations were assessed with the use of flow cytometry 5 d postinfection. Interferon-γ (IFN-γ)-producing cells were assessed with the use of Enzyme-Linked ImmunoSpot assay.Results: Infection changed immune cell populations with more systemic natural killer (NK) cells, memory effector T cells, and major histocompatibility complex II+ cells in infected than noninfected pigs (P < 0.06). Regardless of infection status, HMO-fed pigs had nearly twice as many PBMC NK cells, 36% more MLN effector memory T cells, and 5 times more PBMC basophils than formula-fed pigs (P < 0.04). These populations were intermediate in pigs fed prebiotics. PBMCs from HMO-fed noninfected pigs had twice as many IFN-γ-producing cells as did those from formula-fed noninfected pigs (P = 0.017). The PBMCs and MLNs of formula-fed noninfected pigs had 3 times more plasmacytoid dendritic cells (pDCs) than those of HMO-fed noninfected and formula-fed infected pigs (P < 0.04). In the MLNs, the formula-fed noninfected pigs had more macrophages, pDCs, and mature DCs (P < 0.04) but fewer immature DCs than HMO-fed noninfected pigs (P = 0.022).Conclusions: Dietary HMOs were more effective than prebiotics in altering systemic and gastrointestinal immune cells in pigs. These altered immune cell populations may mediate the effects of dietary HMOs on rotavirus infection susceptibility.

Antibody Repertoire Development in Swine

We describe the domestication of the species, explore its value to agriculture and bioscience, and compare its immunoglobulin (Ig) genes to those of other vertebrates. For encyclopedic information, we cite earlier reviews and chapters. We provide current gene maps for the heavy and light chain loci and describe their polygeny and polymorphy. B-cell and antibody repertoire development is a major focus, and we present findings that challenge several mouse-centric paradigms. We focus special attention on the role of ileal Peyer's patches, the largest secondary lymphoid tissues in newborn piglets and a feature of all artiodactyls. We believe swine fetal development and early class switch evolved to provide natural secretory IgA antibodies able to prevent translocation of bacteria from the gut while the bacterial PAMPs drive development of adaptive immunity. We discuss the value of using the isolator piglet model to address these issues.

The Histological Structure of the Ileal Peyers Patches of the Egyptian Water Buffalo (Bos Bubalus)

The water buffalo represents an important source of animal products in Egypt and characterized by high resistance to several diseases and parasites. The present study carried out on the Egyptian water buffaloes of different ages (from 50 days to 8 years old buffaloes) to illustrate the structure of ileal Payer's patches with age. The specimens of ileum were fixed and processed for light and electrone microscopy The Payer's patches (PPs) formed of elongated dome regions flanked by intestinal villi. These domes were short, wide villi. The domes were consisted of lymphoid follicles covered with a typical dome- associated epithelium of enterocytes and M cells without any goblet cells in young and adult ages. The M cells showed variable appearance depending on the functional status. The lymphoid follicles had a clear germinal center. In conclusion Payer's patches (PPs) were still active until the age of 5 years old and then begin to be inactive at 8 years old we think there is a long period of activity which express the tolerance to many diseases.