Protective Acquired Immunity to Enteromyxum scophthalmi (Myxozoa) is Related to Specific Antibodies in Psetta maxima (L.) (Teleostei)

Abstract

The acquired protection of three groups of turbot that had survived enteromyxosis outbreaks was tested by challenging with E. scophthalmi in three different experiments. The relation of such a response with the kinetics and duration of antibody production (determined by an ELISA) was studied. The progression of the infection was evaluated by PCR. In experiments 1 and 2, in which turbot had cohabited with highly infected fish during outbreaks, parasite prevalence and mortality were very low or null, and there was a progressive and statistically significant increase in the mean antibody production up to 350 and 152 days post‐exposure respectively. By contrast, in experiment 3, fish (coming from non‐infected tanks during the initial outbreak), both infection prevalence and cumulative mortality reached 92.8%, and specific antibodies were detected only in two fish. The observed differences in mortality after challenge appear to be related to the production of specific antibodies and it is probably accompanied by a repertoire of mechanisms of innate immunity. The exploitation of the immune system through breeding selection programmes as a possible strategy to control the disease is discussed.

Complex interaction between proliferative kidney disease, water temperature and concurrent nematode infection in brown trout

“…Therefore, surviving fish were in contact with T. bryosalmonae in the following year, but clinical disease was evident in only a small percentage, indicating at least partimmunity. Protective immunity has been recorded for other myxozoan parasites like Myxobolus cerebralis (Hedrick et al 1998) and Enteromyxum scophthalmi (Sitjà-Bobadilla et al 2007). In this study, the reinfection rate with T. bryosamonae and associated lesions seemed to be influenced again by water temperature and concurrent infection.…”

Light and electron microscopic studies on turbot Psetta maxima infected with Enteromyxum scophthalmi: histopathology of turbot enteromyxosis

“…As a matter of fact, some turbot survive enteromyxosis, and the involvement of a protective acquired immune response related to the production of specific antibodies has been suggested (Sitjà-Bobadilla et al 2007). The reason why few turbot possess the capability to mount an effective response against enteromyxosis is still a matter of study, though the responses at the gastrointestinal level probably play an important role in this enteric infection.…”

Fish immune response to Myxozoan parasites

“…When turbot were challenged with E. scophthalmi, specific antibodies were detected as soon as 48 days p.e. if fish belonged to previously exposed stocks (Sitjà-Bobadilla et al, 2007b), whereas if fish belonged to naïve stocks, they developed the disease and died without producing antibodies at 40-49 days p.e. (Redondo et al, 2002;Sitjà-Bobadilla et al, 2006).…”

“…Parasite, 2008, 15, 420-425 (Sitjà-Bobadilla et al, 2007b). By contrast, for M. cerebralis, acquired immunity was found only among previously exposed fish that developed active infections (Hedrick et al, 1998).…”

“…In fact, they have been suggested as the main mechanism limiting the establishment of ceratomyxosis (Bartholomew, 1998), and contributing to the resistance of rainbow trout M. cerebralis (Ryce, 2003). In turbot enteromyxosis, antibody response takes about 50-100 days to appear (Sitjà-Bobadilla et al, 2005;2007b), whereas some cellular and humoral effectors can be affected from day 20 p.e. .…”