ANTIMICROBIAL ACTIVITY OF CHICKEN AND TURKEY HETEROPHIL PEPTIDES CHP1, CHP2, THP1, AND THP3

Four avian heterophil antimicrobial cationic peptides (Chicken Heterop hil Peptides 1 and 2, and Turkey Heterophil Peptides 1 and 3) were eva luated for in vitro microbicidal activity against selected avian patho gens and human pathogens which are harbored by birds. At concentration s of 16-2 mu g/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 abl e to reduce the survival of Pasteurella multocida by 90% at the maximu m peptide concentration (16 mu g/ml) tested. At 16 mu g/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. Th is peptide, THP3, does not share the same homologous amino acid sequen ce shared by the other three peptides. Under our experimental conditio ns, none of the peptides neutralized Infectious Bronchitis Virus, an e nveloped coronavirus of chickens.