DAO 43:39-48 (2000)  -  doi:10.3354/dao043039

Evaluation of an ELISA and immunoblotting for studying the humoral immune response in Anguillicola crassus infected European eel Anguilla anguilla

K. Knopf1,*, K. Naser2, M. H. T. van der Heijden3, H. Taraschewski1

1Zoologisches Institut ‹ Ökologie, Universität Karlsruhe (TH), Kaiserstr. 12, 76128 Karlsruhe, Germany
2Landesgesundheitsamt Baden-Württemberg, Wiederholdstr. 15, 70174 Stuttgart, Germany
3Wageningen University, Department of Animal Sciences, Fish Culture and Fisheries Group, PO Box 338, 6700 AH Wageningen, The Netherlands
*Present address: Institute of Freshwater Ecology and Inland Fisheries, Department of Inland Fisheries, Müggelseedamm 310, PO Box 850119, 12561 Berlin, Germany. E-mail:

ABSTRACT: The applicability of an enzyme-linked immunosorbent assay (ELISA) for the detection of anguillicolosis in feral eels was examined using a crude antigen preparation from the body wall of adult Anguillicola crassus. The screening consisted of samples from 100 feral European eels Anguilla anguilla. As a reference the actual status of infection was determined by dissection of the eels¹ swimbladders. The ELISA results were compared with a background value calculated from the results obtained from 43 non-infected farm eels. The screened samples had a high prevalence of A. crassus (83%); however, the specificity and the negative predictive value of the ELISA were low compared to the high positive predictive value. Nonetheless, the reproducibility (precision) of the test was satisfactory, and for the non-infected reference group specificity was 97.7%. Although the ELISA, as used in the present study, is not applicable for diagnostic purposes, it represents a useful tool for the investigation of the specific humoral immune response of eels against A. crassus under controlled experimental conditions. Immunoblots using crude antigen preparations from different parts of adult A. crassus as well as a crude somatic third-stage (L3) antigen preparation illustrated that only antigens associated with the body wall of adult A. crassus are potentially suitable for diagnostic purposes. Despite the fact that antibodies against Raphidascaris acus cross-reacted with 3 body wall antigens of A. crassus, the most encouraging results were obtained with the antigen preparation from the outer cuticle of adult A. crassus which yielded a conspicuous, broad band at about 100 kDa.

KEY WORDS: Anguilla anguilla · Anguillicola crassus · Raphidascaris acus · Antigens · Cross-reactivity · Serodiagnosis · ELISA · Immunoblotting

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