Cathelicidins: family of antimicrobial peptides. A review

Abstract

Cathelicidins are small, cationic, antimicrobial peptides found in humans and other species, including farm animals (cattle, horses, pigs, sheep, goats, chickens, rabbits and in some species of fish). These proteolytically activated peptides are part of the innate immune system of many vertebrates. These peptides show a broad spectrum of antimicrobial activity against bacteria, enveloped viruses and fungi. Apart from exerting direct antimicrobial effects, cathelicidins can also trigger specific defense responses in the host. Their roles in various pathophysiological conditions have been studied in mice and humans, but there are limited information about their expression sites and activities in livestock. The aim of the present review is to summarize current information about these antimicrobial peptides in farm animals, highlighting peptide expression sites, activities, and future applications for human and veterinary medicine.

Distinctive Structural Hallmarks and Biological Activities of the Multiple Cathelicidin Antimicrobial Peptides in a Primitive Teleost Fish

“…A ntimicrobial peptides represent an evolutionarily old component of the innate immune system in all organisms (1,2). They form the first line of host defense against infectious microorganisms prior to stimulating the adaptive immune system of animals (1)(2)(3).…”

“…They form the first line of host defense against infectious microorganisms prior to stimulating the adaptive immune system of animals (1)(2)(3). The increasing resistance of bacteria to conventional antibiotics stimulates the exploitation of antimicrobial peptides as candidates for new antibiotics (3,4).…”

“…The increasing resistance of bacteria to conventional antibiotics stimulates the exploitation of antimicrobial peptides as candidates for new antibiotics (3,4). Among them, cathelicidins and defensins represent the major and well-studied antimicrobial peptide families in animals (2,5).…”

“…Cathelicidins are likely present in all vertebrates (2,6,7). The discovery of three cathelicidin-like members in the ancient vertebrate hagfish (Myxine glutinosa) implies that cathelicidins already existed ∼450 million years ago (8).…”

“…The discovery of three cathelicidin-like members in the ancient vertebrate hagfish (Myxine glutinosa) implies that cathelicidins already existed ∼450 million years ago (8). Until now, only one cathelicidin antimicrobial peptide (CAMP) has been found in primates (2). Nevertheless, at least six CAMPs have been discovered in other mammals belonging to Euungulata, such as cattle, goat, sheep, and pig, whereas four have been discovered in birds, three in reptiles, and two in amphibians (2,9,10).…”