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


RESULTS
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.


CONCLUSIONS
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.
School of Biotechnology, Southern Medical University, Guangzhou Dadaobei No,1838, Guangzhou, China.
Yan
Y
Li
Yunshan
Y
Ning
Yundan
Y
Wang
Dandan
D
Peng
Yaodong
Y
Jiang
Lili
L
Zhang
Min
M
Long
Jun
J
Luo
Ming
M
Li
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D057134:Antibodies, Neutralizing / Q000276:immunology*; D000918:Antibody Specificity; D018604:Epitope Mapping; D005260:Female; D016481:Helicobacter Infections / Q000276:immunology; D016480:Helicobacter pylori / Q000201:enzymology*; D056724:Immunity, Humoral; D007114:Immunization; D051379:Mice; D008807:Mice, Inbred BALB C; D019151:Peptide Library; D011994:Recombinant Proteins / Q000276:immunology; D014510:Urease / Q000276:immunology*
D000911:Antibodies, Monoclonal; D057134:Antibodies, Neutralizing; D019151:Peptide Library; D011994:Recombinant Proteins; D014510:Urease