Named piscidins after the Latin term "pisces" for fishes, the antibiotics were isolated from mast cells in hybrid striped bass. Mast cells are the most common tissue immune cell found in fish and other vertebrates, including humans. They are present in many tissues, including the skin, gills, and gastrointestinal tract. This is the first time that researchers have isolated a peptide antibiotic from mast cells of any animals, including humans. However, it is unclear whether fish mast cells are from the same lineage as mammal mast cells.
"The peptide antibiotics or piscidins have the potential to fight important bacterial pathogens of both fish and mammals, including multi-drug resistant bacteria," said Ed Noga, professor at the North Carolina State University College of Veterinary Medicine, and head of the research team that made the discovery.
"The antibiotics could be a useful template for designing new drugs because they are novel structures and not related to any known and currently used antibiotic," notes Noga. "With the development of antibiotic-resistant bacteria, there is an urgent need to find new types of antibiotics that can fight these resistant pathogens."
"While mast cells are one of the most common immune cells of vertebrates, their role as a critical line of defense has been uncertain," he added. "However, if any type of peptide antibiotic is also present in human mast cells, it could have important implications for treating human diseases, including asthma, skin allergies and certain types of arthritis, because of the prominent role that mast cells play in these diseases."