Establishment of A1E3 and B1C4 monoclonal antibody-based ELISA for de-tecting circulating antigen of Schistosoma japonicum and its preliminary ap-plication / 中国血吸虫病防治杂志

ABSTRACT

Objective To establish A1E3 and B1C4 monoclonal antibody-based ELISA for detecting circulating antigen of Schistosoma japonicum and explore its application value in the field. Methods The characteristics of A1E3 and B1C4 monoclonal antibodies were analyzed by SDS-PAGE and Western blotting. The SEA-based ELISA was used to evaluate the titers of A1E3 and B1C4. The orthogonal test was used to determine the best concentration of coating antibody B1C4 and optimal working concentra-tion of A1E3-HRP. Under the optimal conditions,the serum samples of 20 acute schistosomiasis cases,46 chronic schistosomiasis cases,and 20 control sera were tested to evaluate its detection sensitivity and specificity. Seventy-two antibody positive serum sam-ples from Jiangling County of Hubei Province were detected and compared to a commercially available ELISA kit,to evaluate the detection effects of this method. Results The results of SDS-PAGE demonstrated that the purified A1E3 and B1C4 contained a clear heavy chain with molecular weight of 88 000 and 52 000 respectively and had the same light chain with molecular weight of 20 000;while Western blotting demonstrated that A1E3 and B1C4 could be recognized by SEA and serum samples of acute schis-tosomiasis cases. The SEA-based ELISA demonstrated the titers of B1C4 and A1E3 were 1∶105 and 1∶30 000,respectively. The serum samples from all the acute cases and 86.9% of the chronic cases showed a positive reaction. All of the control sera from healthy persons gave a negative response. The positive rates of the double monoclonal antibody ELISA and commercial ELISA for detecting the circulating antigen were 45.8%and 43.1%respectively,and there was no significant difference between the results of the two methods. Conclusion A1E3 and B1C4 monoclonal antibody-based ELISA is established successfully. It exhibits a high sensitivity and specificity in detecting circulating antigen of Schistosoma japonicum.