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Antimicrobial activity of chicken and turkey heterophil peptides CHP1, CHP2, THP1, and THP3
E W Evans1, F G Beach, K M Moore
1Department of Veterinary Pathology, University of Georgia, Athens, USA. EvansE@svm.vetmed.wisc.edu
Abstract:
Four avian heterophil antimicrobial cationic peptides (Chicken Heterophil Peptides 1 and 2, and Turkey Heterophil Peptides 1 and 3) were evaluated for in vitro microbicidal activity against selected avian pathogens and human pathogens which are harbored by birds. At concentrations of 16-2 micrograms/ml, all four avian peptides effected a greater than 90% reduction in the survival of Candida albicans, Salmonella enteriditis, and Campylobacter jejuni. None of the peptides, including the known antimicrobial peptide protamine (used as a positive control), were able to reduce the survival of Pasteurella multocida by 90% at the maximum peptide concentration (16 micrograms/ml) tested. At 16 micrograms/ml, the turkey peptide THP3 did not effect a 90% reduction in survival of Bordetella avium, Escherichia coli, or Salmonella typhimurium, while all of the other peptides tested were effective at this concentration or less. This peptide, THP3, does not share the same homologous amino acid sequence shared by the other three peptides. Under our experimental conditions, none of the peptides neutralized Infectious Bronchitis Virus, an enveloped coronavirus of chickens.
Insights
Four avian antimicrobial peptides show significant in vitro activity against common pathogens like Candida albicans and Salmonella. However, Pasteurella multocida and Infectious Bronchitis Virus were resistant to these peptides.
Area of Science:
- Veterinary Microbiology
- Antimicrobial Peptides
- Infectious Disease
Background:
- Avian pathogens pose significant threats to poultry health and food safety.
- Antimicrobial cationic peptides (ACPs) are crucial components of innate immunity with broad-spectrum activity.
- Understanding the efficacy of avian ACPs against relevant pathogens is essential for developing novel therapeutics.
Purpose of the Study:
- To evaluate the in vitro microbicidal activity of four avian heterophil antimicrobial cationic peptides.
- To assess the peptides' effectiveness against a panel of avian and human pathogens harbored by birds.
- To compare the activity of different avian ACPs and identify potential limitations.
Main Methods:
- In vitro microbicidal assays were performed on four avian ACPs: Chicken Heterophil Peptides 1 and 2 (CHP1, CHP2), and Turkey Heterophil Peptides 1 and 3 (THP1, THP3).
- Peptide activity was tested against Candida albicans, Salmonella enteriditis, Campylobacter jejuni, Pasteurella multocida, Bordetella avium, Escherichia coli, Salmonella typhimurium, and Infectious Bronchitis Virus.
- Protamine was used as a positive control for antimicrobial activity.
Main Results:
- All four peptides demonstrated >90% reduction in survival for C. albicans, S. enteriditis, and C. jejuni at concentrations of 2-16 µg/ml.
- No tested peptides, including protamine, achieved >90% reduction against P. multocida at 16 µg/ml.
- THP3 showed reduced efficacy against B. avium, E. coli, and S. typhimurium compared to other peptides, and lacks sequence homology with them.
- None of the peptides neutralized Infectious Bronchitis Virus.
Conclusions:
- Avian heterophil peptides exhibit potent in vitro antimicrobial activity against specific bacterial and fungal pathogens.
- Certain pathogens, such as P. multocida and avian viruses like Infectious Bronchitis Virus, display resistance to these peptides.
- Structural variations, as seen in THP3, may influence the spectrum of antimicrobial activity, warranting further investigation.