Clonorchiasis is a common zoonosis in southern and northeastern parts of China, especially in Guangdong, Guangxi and Jilin province. Anti-Clonorchis sinensis antibody detection by
enzyme-linked
immunosorbent assay (ELISA) has been used for epidemiological surveys of
clonorchiasis for its convenience and celerity, but it is still a meaningful work to screen ideal diagnostic
antigen or antibody subtype for improvement of diagnostic sensitivity and specificity and for judgement of curative effect. In the present study, recombinant CsCatL-propeptide (rCsCatL-propeptide) was highly expressed in form of inclusion body in Escherichia coli. Soluble rCsCatL-propeptide with high purity were obtained after purification in denatured condition by using His Bind Purification kit, and then renatured. The major antibody subtypes responding to rCsCatL-propeptide in sera from
clonorchiasis patients were
IgG1 and
IgG4, but the level of
IgG4 was more predominant (P < 0.05). The sensitivity of specific
IgG4 detection (91.7%) was statistically significantly higher than that of
IgG1 (25.0%) with rCsCatL-propeptide (P < 0.01). The specificities of
IgG1 and
IgG4 detection with rCsCatL-propeptide were 83.3% and 88.5%, respectively, and the difference between them was not statistically significant (P > 0.05). Cross-reactions took place when we detected
IgG1 of sera from patients infected with Schistosoma japonicum, Paragonimus westermani, hookworm, Trichuris trichiura and Ascaris lumbricoides with rCsCatL-propeptide, while cross-reactions only took place in sera from patients infected with S. japonicum and P. westermani when we detected specific
IgG4. The positive rate of
IgG4 detection in sera from
clonorchiasis patients with <1,000, 1,000-4,999, 5,000-9,999, and ≥10,000 eggs per gram faeces (EPG) were 76.9%, 89.3%, 95.6%, and 100.0%, respectively. The positive rates of serodiagnosis correlated well with the EPG (r = 0.93). Overall, rCsCatL-propeptide is a valuable candidate for specific
IgG4 detection in sera from
clonorchiasis patients by the method of ELISA for its few cross-reaction and acceptable sensitivity. In addition, specific
IgG4 detection can be used to valuate infected degree and
therapeutic effect of
clonorchiasis patients.