Milk Peptides and Immune Response in the Neonate
Bioactive peptides encrypted within the native milk proteins can be released by enzymatic proteolysis, food processing, or gastrointestinal digestion. These peptides possess a wide range of properties, including immunomodulatory properties. The first months of life represent a critical period for the maturation of the immune system because a tolerance for nutrient molecules should be developed while that for pathogen-derived antigens is avoided. Evidence has accumulated to suggest that milk peptides may regulate gastrointestinal immunity, guiding the local immune system until it develops its full functionality. Our data using the weaning piglet as the model suggest that several milk peptides can downregulate various immune properties at a time (one to two weeks after weaning) that coincides with immaturity of the immune system. The protein kinase A system and/or the exchange protein directly activated by cyclic AMP (Epac-1) are implicated in the mechanism through which milk peptides can affect immune function in the early postweaning period. Despite the fact that the research in this field is in its infancy, the evidence available suggests that milk protein peptides may promote development of neonatal immune competence.
Milk contains a variety of components that provide immunological protection and facilitate the development of neonatal immune competence. Two main categories of milk compounds are thought to be associated with immunological activity. The first category includes cytokines, which neonates do not produce efficiently. Cytokines present in milk are thought to be protected against intestinal proteolysis and could alleviate immunological deficits, aiding immune system maturation (Kelleher&Lonnerdal, 2001; Bryan et al., 2006). The second category of milk compounds includes milk protein peptides. Milk peptides may affect mucosal immunity possibly by guiding local immunity until it develops its full functionality (Baldi et al., 2005). This chapter focuses on the effects of milk peptides on immune function and attempts to provide an overview of the knowledge available in this field.
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- Aronoff, D. M., Canetti, C., & Peters-Golden, M. (2004). Prostaglandin E2 inhibits alveolar macrophage phagocytosis through an E-prostanoid 2 receptor-mediated increase in intracellular cyclic AMP. Journal of Immunology, 173, 559–563.Google Scholar
- Chronopoulou, R., Xylouri, E., Fegeros, K., & Politis, I. (2006). The effect of two bovine β-casein peptides on various functional properties of porcine macrophages and neutrophils: Differential roles of protein kinase A and exchange protein directly activated by cyclic AMP-1. British Journal of Nutrition, 96, 553–561.Google Scholar
- Clare, D. A., & Swaisgood, H. E. (2000). Bioactive milk peptides: A prospectus. Journal of Dairy Science, 83, 1187–1195.Google Scholar
- Dent, G., Giembycz, M. A., Rabe, K. F., Wolf, B., Barnes, P. J., & Magnussen, H. (1994). Theophylline suppresses human alveolar macrophage respiratory burst through phosphodiesterase inhibition. American Journal of Respiratory Cell and Molecular Biology, 10, 565–572.Google Scholar
- Fragou, S., Fegeros, K., Xylouri, E., Baldi, A., & Politis, I. (2004). Effect of vitamin E supplementation on various functional properties of macrophages and neutrophils obtained from weaned piglets. Journal of Veterinary Medicine. A, Physiology, Pathology, Clinical Medicine, 51, 1–6.Google Scholar
- Gill, H. S., Doull, F., Rutherfurd, K. J., & Cross, M. L. (2000). Immunoregulatory peptides in bovine milk. British Journal of Nutrition, 84, S111–S117.Google Scholar
- Kapsokefalou, M., Alexandropoulou, I., Komaitis, M., & Politis, I. (2005). In vitro evaluation of iron solubility and dialyzability of various iron fortificants and of iron-fortified milk products targeted for infants and toddlers. International Journal of Food Sciences and Nutrition, 56, 293–302.CrossRefGoogle Scholar
- Kelleher, S. L., & Lonnerdal, B. (2001). Immunological activities associated with milk. Advances in Nutritional Research, 10, 39–65.Google Scholar
- Olivares, M., Diaz-Ropero, M. P., Gomez, N., Lara-Villoslada, F., Sierra, S., Maldonado, J. A., Martin, R., Rodriguez, J. M., & Xaus, J. (2006). The consumption of two new probiotic strains, Lactobacillus gasseri CECT 5714 and Lactobacillus coryniformis CECT 5711, boosts the immune system of healthy humans. International Microbiology, 9, 47–52.Google Scholar
- Rowe, J., Finlay-Jones, J. J., Nicholas, T. E., Bowden, J., Morton, S., & Hart, P. H. (1997). Inability of histamine to regulate TNF-α production by human alveolar macrophages. American Journal of Respiratory Cell and Molecular Biology, 17, 218–223.Google Scholar
- Wattrang, E., Wallgren, P., Lindberg, A., & Fossum, C. (1998). Signs of infections and reduced immune functions at weaning of conventionally reared and specific pathogen free pigs. Zentralblatt für Veterinärmedizin. Reihe B, 45, 7–17.Google Scholar