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Epithelial antimicrobial peptides: innate local host response elements
1Clinical Research Unit, Department of Dermatology, University of Kiel, Germany. jschroeder@dermatology.uni-kiel.de
Abstract:
Multicellular organisms have to survive in an environment laden with numerous microorganisms, which represent a potential hazard to life. Different strategies have been developed to ward off infections by preventing microorganisms from entering surfaces and by preventing the attack of microorganisms that have already entered the epithelia. Therefore, it is not surprising that epithelia are equipped with various antimicrobial substances that act rapidly to kill a broad range of microorganisms. This review summarizes our present knowledge about epithelial peptide antibiotics produced in plants, invertebrates, and vertebrates including humans. There is now strong evidence that in addition to constitutively secreted peptide antibiotics, others are induced upon contact with microorganisms or by proinflammatory cytokines. beta-Defensins represent one family of vertebrate antimicrobial peptides, members of which are inducible and have recently been identified in humans. The defensin-characteristic local expression pattern may indicate that specialized surfaces express a characteristic surface antimicrobial peptide pattern that might define the characteristic microflora as well as the density of microorganisms present on the surface.
Insights
Epithelial cells produce antimicrobial peptides to defend against microbes. These natural antibiotics, including beta-defensins, are crucial for innate immunity and maintaining healthy microbial communities on body surfaces.
Area of Science:
- Microbiology
- Immunology
- Biochemistry
Background:
- Multicellular organisms face constant microbial threats.
- Epithelial surfaces are primary barriers against pathogen invasion.
- Antimicrobial substances are essential for host defense.
Purpose of the Study:
- To review knowledge on epithelial peptide antibiotics across diverse species.
- To highlight the role of inducible antimicrobial peptides in host defense.
- To discuss the significance of beta-defensins in human immunity.
Main Methods:
- Literature review of studies on epithelial antimicrobial peptides.
- Analysis of findings on constitutive and induced peptide secretion.
- Examination of beta-defensin expression and function.
Main Results:
- Epithelial peptide antibiotics are found in plants, invertebrates, and vertebrates.
- Secretion of these peptides can be constitutive or induced by microbes and cytokines.
- Beta-defensins are inducible antimicrobial peptides identified in humans.
Conclusions:
- Epithelial peptide antibiotics are vital for innate immunity.
- Inducible peptides, like beta-defensins, play a key role in responding to microbial challenges.
- Specific antimicrobial peptide patterns on surfaces may shape the local microbiome.