TWENTY-SECOND ANNUAL EASTERN FISH HEALTH WORKSHOP ROYAL PAVILLION RESORT, ATLANTIC BEACH, NC MARCH 18 - 20, 1997 Characterization Of Trout Peritoneal Neutrophils James Daly, Katie Carmen and Christian Stauffer, Division of Natural Sciences, Purchase College, State University of New York, 735 Anderson Hill Rd., Purchase, NY 10577 Two principal phagocytic cells types have been described in fish immunology, the neutrophil and the monocyte/macrophage. In both catfish and carp much is known about these two cells. In salmonids, however, although much is known about the macrophages, little research has been undertaken with the neutrophils. Trout peritoneal exudate cells were obtained from either brook trout (Salvelinus fontinalis) or rainbow trout (Oncorhynchus mykiss) 18-24 h after the injection of 3% glycogen. Neutrophils were then partially purified using discontinuous Percoll gradients. Typically macrophages co-purified with the neutrophils, however, enriched macrophage or neutrophil fractions were also obtained. Peritoneal exudate cells obtained at 48 or 72 h contained macrophages, but no neutrophils. Unlike the macrophages which easily adhere to plastic surfaces and glass coverslips, the neutrophils did not adhere. Phagocytic activity of the neutrophils was tested using neutrophils cell suspensions and Aeromonas salmonicida strain DS which is hydrophobic, but lacks expression of the cytotoxin. Cell suspensions were stained with either Diff-Quik or Leucostat staining kits after the neutrophil and macrophage containing cell fractions were centrifuged onto coverslips. Relative to macrophages, the neutrophils were found to be only poorly phagocytic. Return to 22nd Annual Eastern Fish Health Workshop Return to Leetown Science Center Home Page