Helicobacter pylori specific immune response induced by conservative flagellin linear B-cell epitope.
OBJECTIVE
To testify the immunogenicity of a conservative B-cell linear epitope of Helicobacter pylori (H pylori) flagellin A.


METHODS
Different programs were used to analyze the secondary structure, molecular hydropathy, and surface accessibility of H pylori flagellin A. Linear B-cell epitopes were estimated based on the structural and physiochemical information. Analysis of residue divergence was proposed to screen a conservative linear epitope. The 29-peptide (Pep29mer) synthesized by chemical method, including the predicted conservative B-cell epitope and a known K2d compatible T-cell epitope, was used to immunize mice, and then H pylori-specific antibodies were detected by ELISA.


RESULTS
Based on the analyses of divergent amino acid residues, structural and physiochemical characteristics, it was strongly suggested that the short fragment NDSDGR was the core of a conservative linear epitope in flagellin A. Animals immunized by Pep29mer acquired efficient immune response. In detail, serum H pylori-specific IgA and IgG1 increased significantly in immunized group, while IgG2a only had an insignificant change. H pylori-specific IgA in gastrointestinal flushing fluid also increased significantly.


CONCLUSIONS
The conservative short fragment NDSDGR is the core of a linear B-cell epitope of flagellin A.
Ji
Wan-Sheng
WS
Department of Internal Medicine, Weifang Medical College, Weifang 261042, Shandong Province, China. jiwsh@wfmc.edu.cn
Hu
Jia-Lu
JL
Wu
Kai-Chun
KC
Qiu
Jun-Wen
JW
Han
Zhe-Yi
ZY
Ding
Jie
J
Fan
Dai-Ming
DM
D000595:Amino Acid Sequence; D000818:Animals; D000942:Antigens, Bacterial / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000276:immunology; D005408:Flagellin / Q000276:immunology*; D005750:Gastric Juice / Q000276:immunology; D016480:Helicobacter pylori / Q000276:immunology*; D007070:Immunoglobulin A / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D051379:Mice; D008969:Molecular Sequence Data
D000942:Antigens, Bacterial; D000939:Epitopes; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D005408:Flagellin