Production of mouse monoclonal antibodies against Helicobacter pylori Lpp20 and mapping theantigenic epitope by phage display library

摘要

Lpp20, an outer membrane protein of Helicobacter pylori (H. pylori), has been identified as an immunodominant antigen. To obtain mouse monoclonal antibodies (m Abs) against it and to map its antigenic epitope is potentially to develop a vaccine for prevention and treatment of H. pylori infection. In our study, the Lpp20 gene was obtained from H. pylori genomic DNA by PCR (Gen Bank accession no. DQ106902), cloned into p GEX-4T-l vector and expressed in Escherichia coli (E. coli) as a recombinant fusion protein with grutathione-S-transferase (GST), which was purified by GST-affinity chromatography. m Abs were produced by the hybridoma technique using Lpp20-GST as the immunogen. Using m Ab as the target molecule and immunoscreening phage-displayed random dodecapeptide library (Ph.D.-12), the positive phage clones were sequenced and analyzed. Phage clones were chosen to immunize mice to evaluate the potential of phagotopes as effective vaccines. One mimotope (SWPLYSDASGLG) showed a good match with the Lpp20 proteins at 114-117aa (DASG) and the serum of mice induced by the phage clone clearly recognized Lpp20 protein. Our work suggests that the antigenic epitope could be mapped through screening the phage-displayed peptide libraries with m Ab and a mimotope of Lpp20 providing an alternative approach for the diagnosis and development of a vaccine for H. pylori.