Abstract
The biological functions of avian cathelicidins are poorly defined. Inmammals,cathelicidins have shownto
possess potent broad-range antimicrobial activity aswell as immunomodulatory activities. Therefore,we
investigated the microbicidal activities and localization of Cathelicidin-2 in non-infected and Salmonellachallenged
broiler chickens. Using immunohistochemistry, Cathelicidin-2 was shown to be abundantly
present in heterophils, localized in the large rod-shaped granules, but absent in other peripheral blood
cells and intestinal epithelial cells. Cathelicidin-2 synthesis was observed to be initiated at the early
promyelocyte stage. Considerable infiltration of Cathelicidin-2 containing heterophilswas observed in the
jejunum of Salmonella enteritidis-challenged broilers within 8 h post-infection. Heterophilswere shownto
release mature Cathelicidin-2 peptide upon stimulation with Salmonella-derived LPS in a time-dependent
way. Processing of the Cathelicidin-2 precursor was mediated by serine proteases with a divalent cation
dependency. Cathelicidin-2 peptide showed potent bactericidal and fungicidal activity against all tested
microorganisms, including chicken-specific Salmonella isolates. These results underscore the importance
of avian heterophils as a first line of defence against invading pathogens and implicate that via heterophilmediated
release, cathelicidins may greatly contribute to avian innate immunity.
possess potent broad-range antimicrobial activity aswell as immunomodulatory activities. Therefore,we
investigated the microbicidal activities and localization of Cathelicidin-2 in non-infected and Salmonellachallenged
broiler chickens. Using immunohistochemistry, Cathelicidin-2 was shown to be abundantly
present in heterophils, localized in the large rod-shaped granules, but absent in other peripheral blood
cells and intestinal epithelial cells. Cathelicidin-2 synthesis was observed to be initiated at the early
promyelocyte stage. Considerable infiltration of Cathelicidin-2 containing heterophilswas observed in the
jejunum of Salmonella enteritidis-challenged broilers within 8 h post-infection. Heterophilswere shownto
release mature Cathelicidin-2 peptide upon stimulation with Salmonella-derived LPS in a time-dependent
way. Processing of the Cathelicidin-2 precursor was mediated by serine proteases with a divalent cation
dependency. Cathelicidin-2 peptide showed potent bactericidal and fungicidal activity against all tested
microorganisms, including chicken-specific Salmonella isolates. These results underscore the importance
of avian heterophils as a first line of defence against invading pathogens and implicate that via heterophilmediated
release, cathelicidins may greatly contribute to avian innate immunity.
| Original language | English |
|---|---|
| Pages (from-to) | 1517-1526 |
| Number of pages | 10 |
| Journal | Molecular Immunology |
| Volume | 46 |
| Publication status | Published - 2009 |
Keywords
- Antimicrobial peptide
- Cathelicidin
- Chicken
- Heterophils
- Innate Immunity
- Salmonella enteritidis