Synthesis of dominant epitopes on Nª²terminal part of BPI and preparation of corresponding antisera

    CHEN Yanª²qiu, PENG Zhi, LONG Jun, ZHANG Guoª²min, LU Zhe, AN Yunª²qing*

    Department of Immunology, Capital Medical University, Beijing 100069, China

    [Abstract] AIM: To synthesize B cell dominant epitopes on Nª²terminal part of bactericidal/permeability increasing protein (BPI) and prepare the corresponding antisera. METHODS: The antigenicity, hydrophilicity, flexibility, surface probability and secondary structure of Nª²terminal amino acids 1-199 on BPI were predicted by bioinformatics applications. Two antigen peptides TA/IK were designed and synthesized on the basis of the above analysis. Then the TA/IK were respectively conjugated to keyhole limpet hemocyanin (KLH) and injected into rabbits to prepare corresponding antisera. Indirect ELISA was performed to analyze the antigenicity of TA/IK and to test the titer of the antisera. And Western blot was used to identify the specificity of the antisera. RESULTS: (1)Two B cell epitopeª²based peptides TA/IK were successfully synthesized; (2)the peptides could bind to commercial polyclonal antibody, antiª²BPI55; (3)titers of the antisera against TA/IK were up to 1¡Ã51200, 1¡Ã25600, respectively; (4)Western blot analysis revealed that these antisera could specifically react with the standard sample of BPI55. CONCLUSION: The two synthetic antigen peptides TA/IK are indeed dominant epitopes of BPI Nª²terminal part, and the corresponding antisera are competent for detecting and identifing the Nª²terminal fragments of BPI. ......