Biodefense Properties of Milk: The Role of Antimicrobial Proteins and Peptides

Abstract

Mammary fluids, colostrum and milk, deliver nature's first host defense systems upon birth, and these essential liquids are critical for survival of the neonate. The identification and characterization of anti-infectious proteins were among the early scientific discoveries and this group of proteins has long been recognized for promoting health benefits in both newborns and adults. Among the more widely studied are the immunoglobulins, lactoperoxidase, lysozyme, and lactoferrin. Recently, it was shown that alpha--lactalbumin may also function in a protective capacity dependent upon its folding state. Some of these, especially lactoferrin, also display an immunomodulatory role in which case a totally separate cascade of host defense responses is initiated. It was noted that the mechanism of action for this cluster of sentry proteins does vary; thus, this protective strategy provides for a broad range of responsive reactions to infection. Presently, there is a major focus on the discovery of novel peptides that can be generated from existing milk proteins via proteolytic reactions. To date, this substrate list includes alpha--lactalbumin, beta-lactoglobulin, all casein fractions, and lactoferrin. Again, the immunoregulatory effects prompted as a result of the appearance of these peptides are currently being defined. Herein, we review the principal biological properties associated with each of these contributing milk components with a special emphasis on the role of biodefensive milk peptides. We envision future contributions emerging from this research field as an opportunity to develop effective new therapies to be used in treating infectious diseases and promoting health benefits in vivo.

Growth of bifidobacteria in mammalian milk

“…It hydrolyses β (1,4) linkage between N-acetylglucosamine and N-acetylmuramic acid in peptidoglycan of the bacterial cell wall. This non-specific immunological component is found in human milk at a concentration 3000 times higher than in milk from other animal species (Clare et al, 2003). Cow's and goat's milks possess very low levels of lysozyme (0.16 and 0.23 mg/l) relative to human milk (400 μg/ml) (Chandan et al, 1968;Clare et al, 2003), as confirmed by our results in Table 2.…”

Surveillance of Milk Adulteration and its Influence on Physico-Chemical Characteristics of Milk in Hyderabad, Pakistan

“…Due to the spread of small holding farmers and consequent supply chain complexities, milk handling processes in the traditional system The adulteration of milk may cause significant problems for human health for example; the milk adulterated with contaminated water is a serious health hazard because of potential waterborne diseases (Leghari et al, 2017;Pirzada et al, 2016). Other adultrants like, urea, caustic soda, formaline, hydrogen peroxide, starch, boric acid etc., in milk can cause food poisoning, vomiting, nausea, hypertension, aging, as well as heart, liver and kidney diseases (Ayub et al, 2007;Butt, 2011;Clare et al, 2003;Rideout et al, 2008;See et al, 2010). Feeling gravity of problem, present work has been designed to investigate the common adulterations practiced in market milk of Hyderabad city, and also influence of those adulterations on physicochemical characteristics of milk.…”

Host-defence-related proteins in cows’ milk

“…These include minerals and vitamins such as calcium and vitamins A and D (Hollis et al, 1982;Flynn, 1992), a range of signalling molecules such as cytokines -E-mail: tom.wheeler@agresearch.co.nz (Goldman et al, 1996), IGF-1, and growth hormone (Koldovsky and Thornburg, 1987), bioactive oligosaccharides (Newburg, 2009), bioactive lipids (Isaacs, 2001) and a range of proteins and peptides at lower abundance than the caseins, among which are those whose function is associated with hostdefence (Clare et al, 2003). Many of these bioactivities have been the subject of previous reviews.…”