title: Interaction between Aeromonas salmonicida and peritoneal macrophages of brook trout (Salvelinus fontinalis).
abstract: The phagocytic and bactericidal properties of peritoneal macrophages obtained from brook trout (Salvelinus fontinalis), injected with either glycogen or a modified Freund's complete adjuvant (MFCA), were evaluated against an avirulent and a virulent strain of Aeromonas salmonicida. Avirulent bacteria were effectively phagocytized and killed by macrophages obtained from fish injected with both irritants. With glycogen-elicited macrophages, no enhancement of killing was observed following opsonization of avirulent bacteria with specific antibodies. A killing index (K.I.) of 38 was obtained, compared to a K.I. of 39 for unopsonized bacteria. When avirulent bacteria were opsonized with complement, the K.I. was increased to 67. Virulent bacteria were less susceptible to the phagocytic and the bactericidal activities of glycogen-elicited macrophages, even after opsonization with antibodies and/or complement, K.I. of 9 to 15. In contrast, MFCA-elicited macrophages showed increased phagocytic and bactericidal activities against both strains. The K.I. of unopsonized virulent bacteria was increased to 47 and 46 compared to K.I. of 4 and 7 obtained with glycogen-elicited macrophages.
mesh_terms: D000333:Aeromonas; D000818:Animals; D005122:Exudates and Transudates / Q000166:cytology; D005620:Freund's Adjuvant; D066298:In Vitro Techniques; D008264:Macrophages / Q000502:physiology*; D010529:Peritoneal Cavity / Q000166:cytology; D010587:Phagocytosis; D012487:Salmonidae / Q000276:immunology*; D014337:Trout / Q000276:immunology*
chemical_list: D005620:Freund's Adjuvant