Cell-mediated immune response and T-like cells in thymectomized Oncorhynchus mykiss (Walbaum) infected with or vaccinated against the pathogenic haemoflagellate Cryptobia salmositica Katz, 1951

Journal of Fish Diseases

2002

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.

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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

Ardelli

Journal of Fish Diseases

2002

“…It has also lost some polypeptide bands and others are antigenically different from those of the pathogen (Woo and Thomas 1991). Extensive studies have been carried out on vaccination and the humoral protection in infected or vaccinated fish (reviewed by Woo 2001); there are indications that cell-mediated immunity is activated and may also be involved in protection (Thomas and Woo 1989b;Feng and Woo 1996;Ardelli and Woo 2002).…”

Section: Introductionmentioning

confidence: 97%

Acquired cell-mediated protection in rainbow trout, Oncorhynchus mykiss , against the haemoflagellate, Cryptobia salmositica

Mehta

2002

Parasitology Research

Disease-free rainbow trout, Oncorhynchus mykiss (Walbaum),were inoculated with either the pathogenic Cryptobia salmositica Katz, 1951 or with the attenuated vaccine strain of the parasite. A number of vaccinated fish were then challenged at 6 weeks post-vaccination with pathogenic C. salmositica. Respiratory burst activity in stimulated macrophages (isolated from infected or vaccinated fish) was demonstrated by detection of released super-oxide anions, and the protein contents in these cells were also determined after the cells were digested. At 5 weeks after infection, the respiratory burst activity of macrophages from infected fish was significantly higher than those in naive and vaccinated fish. In addition, macrophages from vaccinated fish had greater activity than naive fish. Macrophage activity in vaccinated and challenged fish was comparable to that of infected fish. Antibodies were detected (ELISA) at 3 weeks after vaccination and at 5 weeks in infected fish. Complement-fixing antibodies (immune lysis test) were detected in infected fish at 5 weeks post-infection but were not detected in vaccinated fish unless they were challenged with the pathogen, in which case the titre rose rapidly.

“…Humoral and cell-mediated immunity are important components of the protection against C. salmositica in both vaccinated and recovered fish (e.g., [8, 9, 40, 43]).…”

Section: Strategies Against Cryptobia and Cryptobiosismentioning

confidence: 99%

Immunological and Therapeutic Strategies against Salmonid Cryptobiosis

Journal of Biomedicine and Biotechnology

2010

Salmonid cryptobiosis is caused by the haemoflagellate, Cryptobia salmositica. Clinical signs of the disease in salmon (Oncorhynchus spp.) include exophthalmia, general oedema, abdominal distension with ascites, anaemia, and anorexia. The disease-causing factor is a metalloprotease and the monoclonal antibody (mAb-001) against it is therapeutic. MAb-001 does not fix complement but agglutinates the parasite. Some brook charr, Salvelinus fontinalis cannot be infected (Cryptobia-resistant); this resistance is controlled by a dominant Mendelian locus and is inherited. In Cryptobia-resistant charr the pathogen is lysed via the Alternative Pathway of Complement Activation. However, some charr can be infected and they have high parasitaemias with no disease (Cryptobia-tolerant). In infected Cryptobia-tolerant charr the metalloprotease is neutralized by a natural antiprotease, α2 macroglobulin. Two vaccines have been developed. A single dose of the attenuated vaccine protects 100% of salmonids (juveniles and adults) for at least 24 months. Complement fixing antibody production and cell-mediated response in vaccinated fish rise significantly after challenge. Fish injected with the DNA vaccine initially have slight anaemias but they recover and have agglutinating antibodies. On challenge, DNA-vaccinated fish have lower parasitaemias, delayed peak parasitaemias and faster recoveries. Isometamidium chloride is therapeutic against the pathogen and its effectiveness is increased after conjugation to antibodies.