• Parasites, Hosts and Diseases
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• v.29 no.1
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• pp.21-30
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• 1991

An immunohistochemical study was performed to demonstrate comparative antigenicity of each body structure of the liver fluke, Clonorchis sinensis, such as the digestive tract, reproductive organs, excretory system, tegument and suckers. Indirect immunoperoxidase technique was applied, rising formalin-fixed and paraffin-embedded sections of C. sinensis as the antigen. Pooled cat sera obtained 10 weeks after an experimental infection with C. sinensis and peroxidase-conjugated goat anti-cat IgG were used as the primary and secondary antibodies, respectively. The intensity of immunohistochemical stain was very sensitive upon the titers of the primary and secondary antibodies, and their optimum dilutions were found to be 1:1,000∼1:2,000 and 1:1,000, respectively. The intestinal epithelial cells, intestinal content and excretory bladder showed strong positive coloring reactions even at lower titer (1 : 2,000) of the primary antibody, whereas the uterine wall and eggs, vitelline glands, and male reproductive organs showed only weak positive reactions despite an increase in the antibody titer (1:1,000). On the other hand, the suckers, tegument, subtegumental cells and other parenchyme portions did not reveal any positive immunoperoxidase reaction at the same antibody titers. From the above results, it is highly suggested that the most potent antigenicity of C. sinensis occur from their excretory-secretory substances originated from the digestive and excretory organs.

• Parasites, Hosts and Diseases
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• v.29 no.3
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• pp.293-310
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• 1991

Clonorchis sinensis is a common parasite of man in Korea. Researches on the specific antigens of C. sinensis would be valuable not only because those elucidate the molecular characteristics of this fluke but also because it is applicable to immunodiagnosis. Although many monoclonal antibodies have been used in the field of parasite immunology, few articles on monoclonal antibodies against C. sinensis have been published so far. The aim of this study was to analyse C. sinensis antigens recognized by monoclonal antibodies, and to set up ELISA-inhibition test using C. sinensis specific monoclonal antibodies for improved specificity of immunodiagnostic tests. By fusion between spleen cells of the mice immunized with C. sinensis water-soluble crude adult worm antigens and plasmacytoma cells of mouse origin, 29 hybridoma clones secreting anti-C. sinensis monoclonal antibodies were made, and 8 clones among those were found specific. After cell cloning, isotypes of 6 selected specific monoclonal anti- bodies were determined to be IgGl, IgG2b and IgA. Four exposed antigenic determinants of natural infection were recognized by different specific monoclonal antibodies. By enzyme-immunoelectrotransfer blot, 10 KD, 34 KD antigenic determinants were found to be reacted with CsHyb 0714-20, CsHyb 0605-10 monoclonal antibodies, respectively, The antigenic determinant recognized by CsHyb 0714-20 monoclonal antibody was revealed to be located at the surface and parenchyme of a parasite by indirect immunoauorescent antibody technique, and those reacted with CsHyb 0605-10, CsHyb 0714-25 monoclonal antibodies were found at the parenchyme and intestine. The antigenic determinant reacted with CsHyb 0605-23 monoclonal antibody was found mainly around the uterine eggs. Four antigenic determinants recognized by specific monoclonal antibodies were all found to be present in the early eluted fractions of C. sinensis antigens separated by Sephadex G-200 gel filtration. By conventional ELISA, 75% of clonorchiasis cases were found positive, but 7.1% of normal controls and 37.5% of paragonimiasis cases showed false positives. However, by ELISA-inhibition test using C. sinensis specific monoclonal antibody (CsHyb 0605-23), 77.1% of clonorchiasis cases were found positive, and there were no false positives in normal controls or paragonimiasis cases, indicating 100% specificity. The ELISA- inhibition test using monoclonal antibodies was found to have same sensitivity and definitely high specificity in comparison with conventional ELISA for serodiagnosis of human clonorchiasis.