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

• Published in: Journal of Fish Diseases
• Main Authors: Ardelli, B F, Woo, P T K
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2002
• Subjects: Atlantic salmon; Salmo salar
• Online Access: http://dx.doi.org/10.1046/j.1365-2761.2002.00369.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1046%2Fj.1365-2761.2002.00369.x; https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-2761.2002.00369.x

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.