Chemotherapeutic efficacy of praziquantel in rats with protective immunity to Clonorchis sinensis infection.
OBJECTIVE
To study the synergic effect of praziquantel (PZQ) and host acquired immunity on Clonorchis sinensis.


METHODS
Acquired immunity to C. sinensis was induced by immunization with crude adult worm antigen (AW Ag) and excretory-secretory antigen (ES Ag) or infection with C. sinensis metacercariae. The effect was assessed by the worm reduction rate compared with the control groups after challenge infection with 50 metacercariae and treated orally with a subcurative dose of praziquantel (50 mg/kg). Significant test was performed by analysis of variance (ANOVA) and Npar1 way Kruskal-Wallis test. All calculations were performed by PC-SAS system.


RESULTS
1. PZQ was more effective against C. sinensis larvae than against adult worms in the control (P < 0.001), ES Ag (P < 0.01) or crude AW Ag immunization group (P < 0.001). 2. As compared with the control, the worm reduction rate after challenge infection was significantly higher (P < 0.001) in ES Ag immunized group (35.6%) and metacercaria infection group (97.5%) and less in crude AW Ag group (23.4%). The PZQ efficacy was significantly enhanced in ES Ag immunized group.


CONCLUSIONS
The efficacy of PZQ against C. sinensis could be synergically enhanced in rats by inducing host acquired immunity.
Quan
F S
FS
Department of Parasitology, Institute for Tropical Endemic Diseases, Korea University, College of Medicine, Seoul 136-705, Korea.
Lee
H J
HJ
Chung
M S
MS
Lee
J S
JS
Rim
H J
HJ
Joo
K H
KH
D000818:Animals; D000871:Anthelmintics / Q000627:therapeutic use*; D000947:Antigens, Helminth / Q000276:immunology*; D003003:Clonorchiasis / Q000188:drug therapy / Q000276:immunology; D003004:Clonorchis sinensis / Q000276:immunology*; D005260:Female; D007114:Immunization; D008297:Male; D011223:Praziquantel / Q000627:therapeutic use*; D051381:Rats
D000871:Anthelmintics; D000947:Antigens, Helminth; D011223:Praziquantel