A concurrent increasing of natural antibodies and enhancement of resistance to furunculosis in rainbow trout.
In order to compare the respective roles of specific response and non-specific mechanisms in the enhancement of resistance to furunculosis, 2 groups of rainbow trout (Oncorhynchus mykiss) were immunized with supernatants of Aeromonas salmonicida or Escherichia coli cultures. The fish received 4 weekly intraperitoneal injections (70 micrograms of crude proteins). One control group was injected with phosphate-buffered saline, while another was untreated. Specific agglutinins were produced only in the fish immunized with A salmonicida supernatant. Polyspecific natural antibodies were measured using different antigens in an enzyme immunoassay. A significant rise (up to 3 times the mean titer of untreated controls) was observed in the 3 injected groups (even with PBS), which also displayed significant protection against experimental furunculosis (32 to 42% mortality versus 72% in controls). Thus, although the exact significance of natural antibodies still has to be confirmed, the importance of natural defenses and the difficulty in clearly inducing specific protection against furunculosis are confirmed.
INRA, Laboratoire d'ichtyopathologie, Station de Virologie Immunologie Moléculaires, Jouy-en-Josas, France.
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Avrameas
D000333:Aeromonas / Q000276:immunology*; D000372:Agglutination Tests; D000818:Animals; D000907:Antibodies, Bacterial / Q000096:biosynthesis*; D001424:Bacterial Infections / Q000276:immunology / Q000662:veterinary*; D004926:Escherichia coli / Q000276:immunology; D005393:Fish Diseases / Q000276:immunology*; D007124:Immunoenzyme Techniques; D012487:Salmonidae; D014337:Trout
D000907:Antibodies, Bacterial