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.
Michel
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C
INRA, Laboratoire d'ichtyopathologie, Station de Virologie Immunologie Moléculaires, Jouy-en-Josas, France.
Gonzalez
R
R
Bonjour
E
E
Avrameas
S
S
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