[Immunodiagnosis of rabbit clonorchiasis by enzyme-linked immunosorbent assay]

Enzyme-linked immunosorbent assay (ELISA) was successfully applied to the immunodiagnosis of parasitic disease in 1974 by Engvall and Perlmann. In our study, this technic was used to test rabbits infected with Chonorchis sinensis metacercariae experimentally. The optimal conditions for the test were determined and summarized as follows: 1. The optimal concentration of VBS antigen was 4 micrograms/ml, showing the highest O.D. in the detection of ELISA test. 2. Four hundred-fold diluted alkaline phosphatase conjugated goat antirabbit IgG (Sigma company) was selected for the test. 3. One hundred times diluted sera of 15 pre-infected rabbits were tested by ELISA and their mean and standard deviation of O.D. was 0.083 +/- 0.004, which was used as the cut-off value for testing post-infected rabbits. Fifteen rabbits were divided into two groups. Group A and B rabbits were infected one hundred and three hundred metacercariae respectively. Sera and stools were collected from all rabbits before and after infection. In serum examination, antibody was detectable by ELISA test during seven and twenty-one and twenty-eight days after infection. Optical density of fifteen infected rabbits detected by ELISA was significantly higher than before infection. ELISA test was successfully applied to the immunodiagnosis of Clonorchis sinensis infected rabbits.