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Antigen induced suppression (AIS) of antibody responses in atlantic salmon (Salmo salar L.) studied by a panel hapten-carrier antigens
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The Scientific & Social Program: Vth ISDCI Congress
P15 COMPLEMENT CONSUMPTION AND OPSONIZATION BY RENIBACTERIUM SALMONINARUM A.S.Rose and R.P.Levine, Department of Genetics, Washington University University Medical School, St. Louis, MO 63110, USA.
Renibacterium salmoninarum is the causative agent of Bacterial Kidney Disease (BKD) of salmonids. The bacteria depletes the complementmediated haemolytic activity of human and chinook salmon (Onoorhynchus tshawytscha) serum, and the extent of depletion depends on bacterial density. The haemolytic complement activity of human, chinook salmon, channel catfish (Ictalurus punctatus), and rainbow trout (Oncorhynchus mykiss) serum was consumed by the bacteria in the presence of Mg-EGTA suggesting the involvement of the alternative complement pathway. A study of immune adherence indicates that the activation of human complement results in the deposition of the third complement protein, C3b, on the surface of the bacteria. Bacteria incubated in human serum (+/- Mg-EGTA) cause human erythrocytes, which bear the complement receptor CRI that binds human C3b, to agglutinate. The immune adherence depends on C3b binding, for it is inhibited by a goat anti-C3 antibody and a mouse monoclonal antibody directed against the human CRI receptor. The binding of C3b to the surface of R. salmoninarum may be an important factor in the infection process via the promotion of the uptake of the bacterium by macrophages.
P16 ANTIGEN INDUCED SUPPRESSION (AIS) OF ANTI]3ODY RESPONSES IN ATLANTIC SALMON (Salmo salar L.) STUDIED BY A PANEL HAPTEN-CARRIER ANTIGENS. *Jan-Eirik Angell Killie and Trond Ja~rgensen, Foundation of Applied Reseach at the University of Troms¢, P.O.Box 2806 Elverh~y, N-9001 Troms¢, Norway. Antigenic competition or antigen induced suppression (A.IS) of antibody responses against a second, but unrelated antigen or epitope, has for almost a century been known as a concept for regulation and control of immune responses in mammals. However, AIS has not been carefully studied in fish. We report here evidence for AIS in Atlantic salmon, studied in vivo by T-dependant (TD) and Tindependant (TI) hapten-carrier molecules. Our results have repetitively provided evidence that the salmon immune system respond to a panel of hapten-protein antigens in terms of both inter- and intramolecular antigenic competition. The suppression is unspecific and long lasting, but can be abrogated by a second injection of the suppressed antigen or avoided by giving the competing antigens simultaneously at separate injection sites. The magnitude of suppression measured as decreased serum antibody activity in ELISA against protein epitopes, is ranging from 75-98 %, depending on the carrier protein used. AIS is not evident when immunizing with TI antigens (TNP-LPS) indicating AIS to be a TD phenomenon also in salmon. Interestingly, haptenization of LPS enhance the Ab-response against LPS which in purified form are poor antigens in salmon. The mechanism behind AIS is not well understood, but T-suppressor ceils, T-cell derived suppressor factors or humoral factors (i.e. cortisol) acting on the lymphocytes are most likely to be potential candidates to understand this concept of antigen induced unspecific immune regulation. PhylogeneticaUy, this study demonstrate AIS to be one possible principle for regulation and control of immune responses in fish and lower vertebrates akin to AIS i mammals.
The Scientific & Social Program: Vth ISDCI Congress
P15 COMPLEMENT CONSUMPTION AND OPSONIZATION BY RENIBACTERIUM SALMONINARUM A.S.Rose and R.P.Levine, Department of Genetics, Washington University University Medical School, St. Louis, MO 63110, USA.
Renibacterium salmoninarum is the causative agent of Bacterial Kidney Disease (BKD) of salmonids. The bacteria depletes the complementmediated haemolytic activity of human and chinook salmon (Onoorhynchus tshawytscha) serum, and the extent of depletion depends on bacterial density. The haemolytic complement activity of human, chinook salmon, channel catfish (Ictalurus punctatus), and rainbow trout (Oncorhynchus mykiss) serum was consumed by the bacteria in the presence of Mg-EGTA suggesting the involvement of the alternative complement pathway. A study of immune adherence indicates that the activation of human complement results in the deposition of the third complement protein, C3b, on the surface of the bacteria. Bacteria incubated in human serum (+/- Mg-EGTA) cause human erythrocytes, which bear the complement receptor CRI that binds human C3b, to agglutinate. The immune adherence depends on C3b binding, for it is inhibited by a goat anti-C3 antibody and a mouse monoclonal antibody directed against the human CRI receptor. The binding of C3b to the surface of R. salmoninarum may be an important factor in the infection process via the promotion of the uptake of the bacterium by macrophages.
P16 ANTIGEN INDUCED SUPPRESSION (AIS) OF ANTI]3ODY RESPONSES IN ATLANTIC SALMON (Salmo salar L.) STUDIED BY A PANEL HAPTEN-CARRIER ANTIGENS. *Jan-Eirik Angell Killie and Trond Ja~rgensen, Foundation of Applied Reseach at the University of Troms¢, P.O.Box 2806 Elverh~y, N-9001 Troms¢, Norway. Antigenic competition or antigen induced suppression (A.IS) of antibody responses against a second, but unrelated antigen or epitope, has for almost a century been known as a concept for regulation and control of immune responses in mammals. However, AIS has not been carefully studied in fish. We report here evidence for AIS in Atlantic salmon, studied in vivo by T-dependant (TD) and Tindependant (TI) hapten-carrier molecules. Our results have repetitively provided evidence that the salmon immune system respond to a panel of hapten-protein antigens in terms of both inter- and intramolecular antigenic competition. The suppression is unspecific and long lasting, but can be abrogated by a second injection of the suppressed antigen or avoided by giving the competing antigens simultaneously at separate injection sites. The magnitude of suppression measured as decreased serum antibody activity in ELISA against protein epitopes, is ranging from 75-98 %, depending on the carrier protein used. AIS is not evident when immunizing with TI antigens (TNP-LPS) indicating AIS to be a TD phenomenon also in salmon. Interestingly, haptenization of LPS enhance the Ab-response against LPS which in purified form are poor antigens in salmon. The mechanism behind AIS is not well understood, but T-suppressor ceils, T-cell derived suppressor factors or humoral factors (i.e. cortisol) acting on the lymphocytes are most likely to be potential candidates to understand this concept of antigen induced unspecific immune regulation. PhylogeneticaUy, this study demonstrate AIS to be one possible principle for regulation and control of immune responses in fish and lower vertebrates akin to AIS i mammals.