DAO 72:241-252 (2006)  -  doi:10.3354/dao072241

Evidence for widespread distribution of piscidin antimicrobial peptides in teleost fish

U. Silphaduang1,3, A. Colorni2, E. J. Noga1,*

1Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, 4700 Hillsborough Street, Raleigh, North Carolina 27606, USA
2Israel Oceanographic and Limnological Research, Ltd., National Center for Mariculture, PO Box 1212, Eilat 88112, Israel
3Present address: Department of Food Science, University of Guelph, Guelph, Ontario N1G 2W1, Canada
*Corresponding author. Email:

ABSTRACT: Antimicrobial peptides (AMPs) are increasingly recognized as a critical component of the host’s defense against infection. Several types of AMPs have been recently identified from mucosal tissues or immune cells of a number of teleosts. Among these are the piscidins, which are 22 residue, α-helical AMPs that were originally isolated from mast cells of hybrid striped bass Morone saxatilis male × Morone chrysops female. Using an antibody specific for the conserved N-terminal amino acid sequence of piscidin 1, we used immunohistochemistry to probe skin, gill, and gastrointestinal tract of 39 teleosts representing 7 different orders. Nine fish species were piscidin-positive, with all of these species being in the Perciformes, the largest and most evolutionarily advanced order of teleosts. Piscidin-positive cells were identified in speciesbelonging to the families Moronidae, Serranidae, Sciaenidae, Siganidae and Belontidae. Immunopositive cells were usually most consistent with mast cells, although in some species, the granule appearance and tinctorial properties diverged somewhat from those of a typical piscine mast cell. In addition, rodlet cells were piscidin-positive in one member of the family Cichlidae; to our knowledge, it is the first time that a host-associated chemical biomarker has been identified in rodlet cells. Our data suggest that piscidins are present in many evolutionarily advanced teleosts. Piscidin-immunoreactive cells were most common at sites of pathogen entry, including the skin, gill and gastrointestinal tract. These results strongly suggest that piscidins are a widespread and important component of many fishes’ defense against disease.

KEY WORDS: Piscidins · Mast cells · Rodlet cells · Innate immunity · Pisces

Full text in pdf format