[Detection of Angiostrongylus cantonensis circulating antigen by monoclonal antibodies].

Objective: To prepare monoclonal antibodies (McAbs) against soluble antigens of adult worms of Angiostrongylus cantonensis (A. cantonensis) on the purpose to detect CAg of A. cantonensis.

Methods: Female BALB/c mice were immunized with soluble antigens of adult worms of A. cantonensis and the spleen cells were fused with myeloma SP2/0 cells. The hybridoma cell strains were screened by enzyme-linked immunosorbent assay (ELISA) and Western blotting. Two McAbs (3F1 and 4H2) were applied to detect the CAg in the sera of rats and mice infected with A. cantonensis and angiostrongyliasis patients respectively by double antibody sandwich ELISA.

Results: Three McAbs against A. cantonensis adult were obtained. Two McAbs (3F1, 4H2) were identified as IgG1 and one McAb (2A2) was identified as IgM. The titers of culture fluid and ascites was 1:25,600, 1:25,600, 1:12,800 and 1:80,000, 1:80,000, 1:40,000 respectively. Western blotting results showed three McAb could be used to identify 15,000 protein of adult worms of A. cantonensis. The detection rates of the CAg in the sera of infected rats and mice were 84.2% (48/57) and 87.2% (41/47) respectively. The detection rate of the CAg in the sera of angiostrongyliasis patients was 86.4% (19/22), and no cross reactions with sera from patients with schistosomiasis, cysticercosis cellulose, paragonimiasis and trichinellosis were observed. The CAg in the sera from mice examined at different periods after infection revealed positive 2 week after inoculation and the titer of CAg peaked 4 week after inoculation.

Conclusion: A new method of sandwich ELISA with high sensitivity and specificity to detect the serum A. cantonensis CAg has been obtained, it could be applicable to the diagnosis, observation of curative effect and epidemiology of angiostrongyliasis.