Antigen epitope of Helicobacter pylori vacuolating cytotoxin A.
OBJECTIVE
To construct and select antigen epitopes of vacuolating cytotoxin A (VacA) for nontoxic VacA vaccine against Helicobacter pylori (H pylori ) infection.


METHODS
Eleven VacA epitopes were predicted according to VacA antigenic bioinformatics. Three candidates of VacA epitope were constructed through different combined epitopes. The candidate was linked with E. coli heat-labile enterotoxin B (LTB) by a linker of 7 amino acids, and cloned into plasmid pQE-60 in which fusion LTB-VacA epitope was efficiently expressed. To test the antigencity of the candidate, 6 BALB/c mice were treated with the fusion LTB-VacA epitope through intraperitoneal injection. To explore the ability of inhibiting the toxicity of VacA,cantiserum against the candidate was used to counteract VacA that induced HeLa cells to produce cell vacuoles in vitro.


RESULTS
Serum IgG against the candidate was induced in the BALB/c mice. In vitro, the three antisera against the candidate efficiently counteracted the toxicity of VacA, and decreased the number of cell vacuoles by 14.17%, 20.20% and 30.41% respectively.


CONCLUSIONS
Two of the three candidates, LZ-VacA1and LZ-VacA2, can be used to further study the mechanism of vacuolating toxicity of VacA, and to construct nontoxic VacA vaccine against H pylori infection.
Liu
Xiu-Li
XL
Bejing Institute of Biotechnology, 20 Dongdajie Street, Fengtai District, Beijing 100071, China.
Li
Shu-Qin
SQ
Liu
Chun-Jie
CJ
Tao
Hao-Xia
HX
Zhang
Zhao-Shan
ZS
D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology*; D001427:Bacterial Toxins / Q000235:genetics / Q000276:immunology*; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers; D004768:Enterotoxins / Q000235:genetics; D000939:Epitopes / Q000032:analysis; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins; D006367:HeLa Cells; D016480:Helicobacter pylori / Q000235:genetics* / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D051379:Mice; D008969:Molecular Sequence Data; D010957:Plasmids
D001426:Bacterial Proteins; D001427:Bacterial Toxins; D017931:DNA Primers; D004768:Enterotoxins; D000939:Epitopes; D029968:Escherichia coli Proteins; D007074:Immunoglobulin G; C074689:VacA protein, Helicobacter pylori; C027538:heat-labile enterotoxin, E coli