[Immune responses in rabbits infected with Clonorchis sinensis]

Experimental rabbits were divided into single infection group, reinfection group and treatment group. Both eggs per gram of feces and serum antibody were determined periodically by antiformin-ether concentration method and ELISA technic, respectively. Two rabbits were observed 72 weeks and 76 weeks after infection in single infection occasion. Antibody elevated to the maximum during 8 and 14 weeks after infection, and then gradually decreased but still kept in detectable level till the termination of observation. EPG kept in lower intensity and no apparent variation during the period of observation. In periodically re-infected groups, both antibody and EPG increased after every occasion of re-infection. But in rabbits re-infection every month, its antibody were maintained in a high level and kept this level even at the 5th to 7th re-infection. In general, EPG increased less rapidly after several times re-infection. Stool examinations showed negative results, but in antibody variations were not concordant in rabbits after treatment. In un-infected rabbits, antibody kept in negative reaction during the course of observation.