Mimotopes selected with a neutralizing antibody against urease B from Helicobacter pylori induce enzyme inhibitory antibodies in mice upon vaccination

School of Biotechnology, Southern Medical University, Guangzhou Dadaobei No,1838, Guangzhou, China.
BMC Biotechnology (Impact Factor: 2.03). 11/2010; 10(1):84. DOI: 10.1186/1472-6750-10-84
Source: PubMed


Urease B is an important virulence factor that is required for Helicobacter pylori to colonise the gastric mucosa. Mouse monoclonal antibodies (mAbs) that inhibit urease B enzymatic activity will be useful as vaccines for the prevention and treatment of H. pylori infection. Here, we produced murine mAbs against urease B that neutralize the enzyme's activity. We mapped their epitopes by phage display libraries and investigated the immunogenicity of the selected mimotopes in vivo.
The urease B gene was obtained (GenBank accession No. DQ141576) and the recombinant pGEX-4T-1/UreaseB protein was expressed in Escherichia coli as a 92-kDa recombinant fusion protein with glutathione-S-transferase (GST). Five mAbs U001-U005 were produced by a hybridoma-based technique with urease B-GST as an immunogen. Only U001 could inhibit urease B enzymatic activity. Immunoscreening via phage display libraries revealed two different mimotopes of urease B protein; EXXXHDM from ph.D.12-library and EXXXHSM from ph.D.C7C that matched the urease B proteins at 347-353 aa. The antiserum induced by selected phage clones clearly recognised the urease B protein and inhibited its enzymatic activity, which indicated that the phagotope-induced immune responses were antigen specific.
The present work demonstrated that phage-displayed mimotopes were accessible to the mouse immune system and triggered a humoral response. The urease B mimotope could provide a novel and promising approach for the development of a vaccine for the diagnosis and treatment of H. pylori infection.

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Available from: Yundan Wang, Jul 28, 2014
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    • "In the case of mimotope immunization, several studies have shown effective responses in vivo [17]. Importantly, the mimotopes are able to replace the original epitopes for vaccine development [18,19]. Furthermore, active immune responses induced by phage-displayed mimotopes have been verified in many diseases [20-22]. "
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    • "All mimotope clones displayed in the phage were strongly recognized by the 4H11D10B11 mAb, contrary to what was observed with the M13KE phage (without insert) and the phage carrying a mimotope to TsGST25. This suggests that the interactions between the mAb with the peptide displayed on the phage are specific and support the hypothesis that mimotopes mimic the structure of the linear epitope that recognizes the mAb on TTPI, as has been determined in other studies (Cunha-Júnior et al., 2010; Li et al., 2010). "
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    • "Further studies could reveal if those peptides represents mimotopes of the same antigen or of different antigens. Comparison of selected mimotopes and the native antigen sequence could lead to a better understanding of molecular mechanisms that participate in the immune response and the design of peptides for diagnostic purposes [19]. "
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