Proteome profiles of mucosal immunoglobulin uptake in inflamed porcine gut

Does dietary supplementation of pregnant mares with a commercial stud feed balancer improve the transfer of passive immunity in their foals? A controlled field trial

This prospective, controlled field trial aimed to determine the effect of dietary supplementation of mares in late pregnancy with a commercial stud feed balancer on the transfer of passive immunity to their foals. Eighty-two pregnant mares on a single stud farm that were eligible for inclusion were assigned into two groups (Intervention and Control) based primarily on existing social groupings. Between 64-224 days prepartum, all mares received the same forage-based diet but mares in the Intervention group received an in-feed commercial stud feed balancer and mares in the Control group received the stud's home-mix concentrate. Data from 68 mare and foal pairs were analysed according to Intention To Treat (ITT) principles and sensitivity analysis was performed on 57 mare and foal pairs who fulfilled the study protocol. The primary outcome of interest was failure of passive transfer of immunity (FPT), defined as foal IgG <8g/l at 12-36 h after first suckle. Foals of mares in the Intervention group were significantly less likely to develop FPT compared to those in the Control group. Colostral quality (Brix ≥23.0) was also significantly greater in mares in the Intervention compared to the Control group. Group (Intervention vs. Control) and sex of foal were the only variables that were significantly associated with FPT in a multivariable model that explored the effect of other potential risk factors for FPT.

On the influence of the source of porcine colostrum in the development of early immune ontogeny in piglets

The effects on the ontogeny of serum cytokines and immune cells caused by feeding suckling piglets with sow/gilt colostrum and milk replacer was assessed in the present study. After farrowing, the piglets born were randomized into six groups: GG and SS (n = 10/group): piglets were kept with their dam; GS (n = 10): piglets were changed from gilts to sows; SG (n = 10): piglets were changed from sows to gilts; GMR (n = 6) and SMR (n = 8): piglets from either gilts or sows were isolated from the dams and were bottle-fed ad libitum with commercial formula milk replacer. The piglets remained in the groups during the first 24 h of life and were later returned to their respective mothers. Serum immunoglobulin concentration and lymphocyte proliferation from the blood, spleen, thymus, and mesenteric lymph node of the piglets were assessed at 24 h and at 28 days of age. Serum cytokine concentrations were measured through a cytokine multiplex assay at 24 h. Overall, piglets suckling on sows (SS and GS) had a higher concentration of serum immunoglobulin at 24 h, which was also associated with a rise in plasma cytokine concentration and greater ability of B and T cells from lymphatic organs and blood mononuclear cells to respond to mitogens. We suggest a bias towards Th1-, Th2-, and Th17-cell polarizing and cytokines during the suckling period, which may be influenced by maternal immunological factors in the colostrum, such as dam parity. All findings suggest sow parity having a possible role, which may contribute to exerting a modulating action on immune response development.

Potential Benefits of Bovine Colostrum in Pediatric Nutrition and Health

Bovine colostrum (BC), the first milk produced from cows after parturition, is increasingly used as a nutritional supplement to promote gut function and health in other species, including humans. The high levels of whey and casein proteins, immunoglobulins (Igs), and other milk bioactives in BC are adapted to meet the needs of newborn calves. However, BC supplementation may improve health outcomes across other species, especially when immune and gut functions are immature in early life. We provide a review of BC composition and its effects in infants and children in health and selected diseases (diarrhea, infection, growth-failure, preterm birth, necrotizing enterocolitis (NEC), short-bowel syndrome, and mucositis). Human trials and animal studies (mainly in piglets) are reviewed to assess the scientific evidence of whether BC is a safe and effective antimicrobial and immunomodulatory nutritional supplement that reduces clinical complications related to preterm birth, infections, and gut disorders. Studies in infants and animals suggest that BC should be supplemented at an optimal age, time, and level to be both safe and effective. Exclusive BC feeding is not recommended for infants because of nutritional imbalances relative to human milk. On the other hand, adverse effects, including allergies and intolerance, appear unlikely when BC is provided as a supplement within normal nutrition guidelines for infants and children. Larger clinical trials in infant populations are needed to provide more evidence of health benefits when patients are supplemented with BC in addition to human milk or formula. Igs and other bioactive factors in BC may work in synergy, making it critical to preserve bioactivity with gentle processing and pasteurization methods. BC has the potential to become a safe and effective nutritional supplement for several pediatric subpopulations.

Changes in intestinal proteins induced by colostrum uptake in neonatal calves: analysis by two-dimensional gel electrophoresis-based proteomics analysis

Colostrum is a unique source of biological molecules, and the uptake of colostrum immunoglobulin G (IgG) by neonatal calves is related to the success of passive immunity transfer, an important determinant of health and survival. However, studies on colostral IgG uptake in the small intestine by using proteomics approaches have been scarce. In the present study, samples of the duodenum, jejunum and ileum were collected ~2 h after birth from calves not fed colostrum, and 8, 24, and 36 h after birth from calves fed colostrum. Protein samples were extracted and separated by temporal two-dimensional gel electrophoresis, and differential protein spots were identified by mass spectrometry. After colostrum feeding, internalised IgG in the duodenum and jejunum was detected at ~8 and 24 h, and then was barely detected at 36 h after birth. The IgG internalised in the ileum of calves fed colostrum was detected ~24 and 36 h after birth. Beta-lactoglobulin was upregulated in the entire small intestine; these levels were maintained for 24 h and were barely detected thereafter in neonatal calves fed colostrum. Moreover, changes in several proteins in the small intestine were detected after calves received colostrum. The results of the present study showed the distribution and variation of internalised IgG in the duodenum, jejunum and ileum of neonatal calves that received colostrum after birth. These findings indicated that IgG and β-lactoglobulin in the small intestine of calves fed colostrum may be related to their unique bioactive functions, providing a basis for improvements in calf rearing and management.

Historical and contemporary aspects of maternal immunity in swine

Maternal immunity plays a pivotal role in swine health and production because piglets are born agammaglobulinemic and with limited cell-mediated immunity, i.e. few peripheral lymphoid cells, immature lymphoid tissues, and no effector and memory T-lymphocytes. Swine do not become fully immunologically competent until about 4 weeks of age, which means that their compromised ability to respond to infectious agents during the first month of life must be supplemented by maternal immune components: (1) circulating antibodies derived from colostrum; (2) mucosal antibodies from colostrum and milk; and (3) immune cells provided in mammary secretions. Because maternal immunity is highly effective at protecting piglets against specific pathogens, strengthening sow herd immunity against certain diseases through exposure or vaccination is a useful management tool for ameliorating clinical effects in piglets and delaying infection until the piglets' immune system is better prepared to respond. In this review, we discuss the anatomy and physiology of lactation, the immune functions of components provided to neonatal swine in mammary secretion, the importance of maternal immunity in the prevention and control of significant pathogens.

FUT1 genetic variants impact protein glycosylation of porcine intestinal mucosa

A massive use of antibiotics in industrial pig production is a major cause of the rapidly rising bacterial resistance to antibiotics. An enhanced understanding of infectious diseases and of host-microbe interactions has the potential to explore alternative ways to improve pig health and reduce the need for antibiotics. Host-microbe interactions depend on host-expressed glycans and microbe-carrying lectins. In this study, a G > A (nucleotide 307) missense mutation in the porcine α1,2fucosyltransferase 1 gene (FUT1), which has been reported to prevent infections by the common porcine enteric pathogen F18 fimbriated Escherichia coli, provided a unique opportunity to study glycan structures potentially involved in intestinal infections. N- and O-Linked glycans of the intestinal mucosa proteins were characterized in detail using LC-MS/MS. Relative abundances of all glycans were determined and compared between four heterozygous pigs (FUT1-307(A/G)) and four age-matched homozygous pigs from the same 2 litters carrying the missense FUT1 gene constellation (FUT1-307(A/A)). None of the characterized 48 N-linked glycans was found to be regulated by the FUT1 missense mutation, while 11 of the O-linked glycans showed significantly altered abundances between the two genotypes. The overall abundance of H-antigen carrying structures was decreased fivefold, while H-antigen precursors and sialylated structures were relatively more abundant in pigs with the FUT1 missense mutation. These results provide insight into the role of FUT1 on intestinal glycosylation, improve our understanding of how variation in FUT1 can modulate host-microbe interactions, and suggest that the FUT1 genetic variant may help to improve pig gut health.

The Mammary Gland in Mucosal and Regional Immunity

The mammary gland (MG) lacks a mucosa but is part of the mucosal immune system because of its role in passive mucosal immunity. The MG is not an inductive site for mucosal immunity. Rather, synthesis of immunoglobulin (Ig)A by plasma cells stimulated at distal inductive sites dominate in the milk of rodents, humans, and swine whereas IgG1 derived from serum predominates in ruminants. Despite the considerable biodiversity in the role of the MG, IgG passively transfers the maternal systemic immunological experience whereas IgA transfers the mucosal immunological experience. Although passive antibodies are protective, they and other lacteal constituents can be immunoregulatory. Immune protection of the MG largely depends on the innate immune system; the monocytes–macrophages group together with intraepithelial lymphocytes is dominant in the healthy gland. An increase in somatic cells (neutrophils) and various interleukins signal infection (mastitis) and a local immune response in the MG. The major role of the MG to mucosal immunity is the passive immunity supplied to the suckling neonate.

Intestinal proteomics in pig models of necrotising enterocolitis, short bowel syndrome and intrauterine growth restriction

Necrotising enterocolitis (NEC), short bowel syndrome (SBS) and intrauterine growth restriction (IUGR) are three conditions associated with intestinal dysfunction in newborn infants, particularly those born preterm. Piglet (Sus scrofa) models have recently been developed for NEC, SBS and IUGR, and tissue proteomic analyses have identified unknown pathways and new prognostic disease markers. Intestinal HSPs, iron metabolism proteins and proteins related to amino acid (e.g. arginine) and glucose metabolism are consistently affected by NEC progression and some of these proteins are also affected by SBS and IUGR. Parallel changes in some plasma and urinary proteins (e.g. haptoglobin, globulins, complement proteins, fatty acid binding proteins) may mirror the intestinal responses and pave the way to biomarker discovery. Explorative non-targeted proteomics provides ideas about the cellular pathways involved in intestinal adaptation during the critical neonatal period. Proteomics, combined with other -omic techniques, helps to get a more holistic picture of intestinal adaptation during NEC, SBS and IUGR. Explorative -omic research methods also have limitations and cannot replace, but only supplement, classical hypothesis-driven research that investigate disease mechanisms using a single or few endpoints.

Proteomics at the interface of psychology, gut physiology and dysfunction: an underexploited approach that deserves expansion

Gut functions such as digestion and absorption are essential to life and the emerging insights into the gut-brain axis - that is, the cross talk between the enteric and CNS - point towards critical links between (eating) behavior, psychology, whole body and gut physiology, and digestive and overall health. While proteomics is ideally positioned to shed more light on these interactions, be it applied to the periphery (e.g., blood) or the locus of action (i.e., the gut), it is to date largely underexploited, mainly because of challenging sampling and tissue complexity. In view of the contrast between potential and current delivery of proteomics in the context of intestinal health, this article briefs the reader on the state-of-the-art of molecular intestinal research, reviews current proteomic studies (explicitly focusing on the most recent ones that target inflammatory bowel disease patient samples) and argues for an expansion of this research field.

Time-resolved quantitative proteome analysis of in vivo intestinal development

Postnatal intestinal development is a very dynamic process characterized by substantial morphological changes that coincide with functional adaption to the nutritional change from a diet rich in fat (milk) to a diet rich in carbohydrates on from weaning. Time-resolved studies of intestinal development have so far been limited to investigation at the transcription level or to single or few proteins at a time. In the present study, we elucidate proteomic changes of primary intestinal epithelial cells from jejunum during early suckling (1-7 days of age), middle suckling (7-14 days), and weaning period (14-35 days) in mice, using a label-free proteomics approach. We show differential expression of 520 proteins during intestinal development and a pronounced change of the proteome during the middle suckling period and weaning. Proteins involved in several metabolic processes were found differentially expressed along the development. The temporal expression profiles of enzymes of the glycolysis were found to correlate with the increase in carbohydrate uptake at weaning, whereas the abundance changes of proteins involved in fatty acid metabolism as well as lactose metabolism indicated a nondiet driven preparation for the nutritional change at weaning. Further, we report the developmental abundance changes of proteins playing a vital role in the neonatal acquisition of passive immunity. In addition, different isoforms of several proteins were quantified, which may contribute to a better understanding of the roles of the specific isoforms in the small intestine. In summary, we provide a first, time-resolved proteome profile of intestinal epithelial cells along postnatal intestinal development.

Proteomics in nutrition: status quo and outlook for biomarkers and bioactives

Food and beverages are the only physical matter we take into our body, if we disregard the air we inhale and the drugs we may have to apply. While traditional nutrition research has aimed at providing nutrients to nourish populations and preventing specific nutrient deficiencies, it more recently explores health-related aspects of individual bioactive components as well as entire diets and this at group rather than population level. The new era of nutrition research translates empirical knowledge to evidence-based molecular science. Modern nutrition research focuses on promoting health, preventing or delaying the onset of disease, optimizing performance, and assessing risk. Personalized nutrition is a conceptual analogue to personalized medicine and means adapting food to individual needs. Nutrigenomics and nutrigenetics build the science foundation for understanding human variability in preferences, requirements, and responses to diet and may become the future tools for consumer assessment motivated by personalized nutritional counseling for health maintenance and disease prevention. The scope of this paper is to review the current and future aspects of nutritional proteomics, focusing on the two main outputs: identification of health biomarkers and analysis of food bioactives.

Differential composition of proteomes in sow colostrum and milk from anterior and posterior mammary glands

Piglets obtaining milk from anterior and middle mammary glands (MG) grow faster than those suckling posterior MG, but the underlying mechanisms are not clear. The purpose of this study was to investigate the differential proteomes of colostrum and milk secreted by anterior and posterior MG. Six healthy primiparous sows with 7 pairs of MG were used; the first and the second pairs were defined as anterior MG and the sixth and seventh pairs as posterior MG. Colostrum and milk were collected at d 1 and 14 after parturition, respectively. Comparative proteomics analysis was performed to identify the differentially expressed proteins in colostrum and milk secreted by anterior and posterior MG. Results show that protein composition in colostrum and milk varied markedly with the anatomical location of MG. Immunoglobulins, lactadherin, and haptoglobin were upregulated (P < 0.05) in colostrum from anterior MG compared with posterior MG. Concentrations of immunoglobulins and lactoferrin in milk from anterior MG were greater (P < 0.05) than milk from posterior MG. Moreover, concentration of proteins from somatic cells was greater (P < 0.05) in milk from posterior MG compared with anterior MG. Most proteins, in which abundance was upregulated in colostrum and milk from anterior MG, contribute to passive immunity, intestinal development of suckling piglets and epithelial integrity, and the health of MG. Collectively, these results indicate that in comparison with posterior MG, anterior MG are more active in protein synthesis and produce more immunoglobulins and lactoferrin in colostrum and milk.

Humoral and cellular factors of maternal immunity in swine

Immunoglobulins cannot cross the placenta in pregnant sows. Neonatal pigs are therefore agammaglobulinemic at birth and, although immunocompetent, they cannot mount rapid immune responses at systemic and mucosal sites. Their survival depends directly on the acquisition of maternal immunity via colostrum and milk. Protection by maternal immunity is mediated by a number of factors, including specific systemic humoral immunity, involving mostly maternal IgG transferred from blood to colostrum and typically absorbed within the first 36 h of life. Passive mucosal immunity involves local humoral immunity, including the production of secretory IgA (sIgA), which is transferred principally via milk until weaning. The mammary gland (MG) produces sIgA, which is, then secreted into the milk via the poly-Ig receptor (pIgR) of epithelial cells. These antibodies are produced in response to intestinal and respiratory antigens, including pathogens and commensal organisms. Protection is also mediated by cellular immunity, which is transferred via maternal cells present in mammary secretions. The mechanisms underlying the various immunological links between MG and the mucosal surfaces involve hormonally regulated addressins and chemokines specific to these compartments. The enhancement of colostrogenic immunity depends on the stimulation of systemic immunity, whereas the enhancement of lactogenic immunity depends on appropriate stimulation at induction sites, an increase in cell trafficking from the gut and upper respiratory tract to the MG and, possibly, enhanced immunoglobulin production at the effector site and secretion in milk. In addition, mammary secretions provide factors other than immunoglobulins that protect the neonate and regulate the development of mucosal immunity--a key element of postnatal adaptation to environmental antigens.

Immunoglobulins, antibody repertoire and B cell development

Swine share with most placental mammals the same five antibody isotypes and same two light chain types. Loci encoding lambda, kappa and Ig heavy chains appear to be organized as they are in other mammals. Swine differ from rodents and primates, but are similar to rabbits in using a single VH family (VH3) to encode their variable heavy chain domain, but not the family used by cattle, another artiodactyl. Distinct from other hoofed mammals and rodents, Ckappa:Clambda usage resembles the 1:1 ratio seen in primates. Since IgG subclasses diversified after speciation, same name subclass homologs do not exist among swine and other mammals unless very closely related. Swine possess six putative IgG subclasses that appear to have diversified by gene duplication and exon shuffle while retaining motifs that can bind to FcgammaRs, FcRn, C1q, protein A and protein G. The epithelial chorial placenta of swine and the precosial nature of their offspring have made piglets excellent models for studies on fetal antibody repertoire development and on the postnatal role of gut colonization, maternal colostrum and neonatal infection on the development of adaptive immunity during the "critical window" of immunological development. This chapter traces the study of the humoral immune system of this species through its various eras of discovery and compiles the results in tables and figures that should be a useful reference for educators and investigators.