© 1991 Oxford University Press
research-article |
Development of Fish Peritoneal Macrophages as a Model for Higher Vertebrates in Immunotoxicological Studies
I. Characterization of Trout Macrophage Morphological, Functional, and Biochemical Properties1,2
Institute of Environmental Medicine, New York University Medical Center 550 First Avenue, New York, New York 10016
Received July 9, 1990; accepted November 29, 1990
Development of Fish Peritoneal Macrophages as a Model for Higher Vertebrates in Immunotoxicological Studies. I. Characterization of Trout Macrophage Morphological, Functional, and Biochemical Properties. ZELIKOFF, J. T., ENANE, N. A., BOWSER, D., SQUIBB, K. S., AND FRENKEL, K. (1991). Fundam. Appl. Toxicol. 16, 576–589. The immune defense mechanisms of fish are not as well characterized as those of mammals but seem to be related and similarly competent. Because of this, there is an increased interest in the immune responses of fish as models for higher vertebrates in immunotoxicological studies. Prior to such studies, baseline criteria for specific components of the immune response needed to be established. For this study, we have examined trout macrophage morphology using light and scanning electron microscopy, phagocytic activity, random and stimulus-directed migration, and superoxide anion radical ({dot}
) production for resident and lipopolysacharide (LPS) or Aeromonas salmonicidae-elicited rainbow trout (Oncorhynchus mykiss) peritoneal macrophages (M
). Following peritoneal lavage, >89% of the cells were M as determined by differential counts and nonspecific esterase staining. Immunization with LPS and A. salmonicidae increased M number {small tilde}5 and 13-fold, respectively, and overall size. Trout M were phagocytically active engulfing serum opsonized latex particles and were mobile, migrating both randomly and in a directed fashion towards formyl-methionine-L-leucine-L-phenylalanine (FMLP) and trout serum-derived complement fragment C5a. Concentrations of FMLP (100 nM) and C5a (0.01–1%) effective for attracting trout M are the same as those used to attract rabbit M. Resident trout M produced negligable quantities of-({dot}) following stimulation with 1 µg/ml phorbol myristate acetate; Aeromonas-elicited M produced ({dot}) in a time-dependen manner which peaked after 60 min at 2.9 nmol per 2 × 105 cells and then declined. The results of this study provide a data base for future toxicological studies with trout peritoneal M and indicate the usefulness of this system for immunotoxicological studies.