Experimental Cryptobia salmositica (Kinetoplastida) infections in Atlantic salmon, Salmo salar L.: cell-mediated and humoral immune responses against the pathogenic and vaccine strains of the parasite |
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Authors: | B F Ardelli & P T K Woo |
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Institution: | Department of Zoology, University of Guelph, Guelph, Ontario, Canada |
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Abstract: | Hatchery-reared Atlantic salmon, Salmo salar L., were vaccinated intraperitoneally (i.p.) with a live attenuated Cryptobia salmositica vaccine (either 100 000 or 5000 parasites fish?1) and 4 weeks later were challenged with the parasite (either 100 000 or 5000 parasites fish?1). Unvaccinated, infected salmon had high parasitaemias and were anaemic. Fish given a high dose (100 000 parasites fish?1) had higher parasitaemias than fish given the lower dose. Vaccinated fish had low parasitaemias and a mild anaemia, but recovered quickly after challenge. Complement-fixing antibody increased in vaccinated fish after challenge and was highest at 2 weeks post-challenge. The cell-mediated response (both T cells and B cells) was depressed in infected fish until 4 weeks after infection. In vaccinated fish, the humoral response (i.e. B-lymphocytes) was greater than the cell-mediated response (i.e. T-lymphocytes). In contrast, infected fish had a greater cell-mediated than humoral immune response. |
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Keywords: | Atlantic salmon cell-mediated immunity Cryptobia salmositica humoral immunity mitogenic responses vaccination |
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