Diversity of Helicobacter pylori isolates in expression of antigens and induction of antibodies.
OBJECTIVE
To obtain evidence for selection of antigens used in genetically engineered vaccine against Helicobacter pylori (H pylori).


METHODS
Enzyme linked immunoabsorbent assay (ELISA) was established on the basis of recombinant protein antigens rUreB, rHpaA, rVacA, rCagA1, rNapA, rFlaA and rFlaB of H pylori to detect expression rates of the antigens in bacterial isolates as well as positive rates of the antibodies in sera from H pylori-infected patients. PCR was applied to the detection of carrying rates of the genes encoding antigens in the isolates.


RESULTS
The outputs of rUreB, rHpaA, rVacA, rCagA1, rNapA, rFlaA and rFlaB were approximately 35%, 32%, 15%, 23%, 56%, 25% and 20% of the total bacterial proteins, respectively. One hundred and fifty-one strains of H pylori were isolated from 347 biopsy specimens of chronic gastritis, peptic ulcer or gastric adenocarcinoma, with a positive rate of 43.5%. All of the isolates expressed UreB, HpaA, FlaA and FlaB while 52.3%, 92.1% and 93.4% of the isolates expressed VacA, CagA and NapA, respectively. In the sera of 151 H pylori-infected patients, the positive rates of IgG antibodies against UreB, HpaA, VacA, CagA, NapA, FlaA and FlaB were 100%, 87.4%, 43%, 71.5%, 89.4%, 84.8% and 79.5%, respectively. Furthermore, the expression frequencies of VacA and NapA were found to be relative to the severity of gastric diseases (P=0.016 and P<0.0001, respectively).


CONCLUSIONS
UreB antigen is the top option of developing genetically engineered vaccine against H pylori followed by NapA or HpaA.
Tang
Ren-Xian
RX
Department of Medical Microbiology and Parasitology, Xuzhou Medical College, Xuzhou, Jiangsu Province, China.
Luo
Dong-Jiao
DJ
Sun
Ai-Hua
AH
Yan
Jie
J
D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood*; D000942:Antigens, Bacterial / Q000235:genetics / Q000276:immunology*; D001428:Bacterial Vaccines / Q000235:genetics / Q000276:immunology*; D016481:Helicobacter Infections / Q000276:immunology / Q000382:microbiology* / Q000517:prevention & control; D016480:Helicobacter pylori / Q000276:immunology* / Q000302:isolation & purification / Q000472:pathogenicity; D006801:Humans; D011817:Rabbits; D011994:Recombinant Proteins / Q000276:immunology; D014614:Vaccines, Synthetic / Q000276:immunology; D037521:Virulence Factors / Q000276:immunology
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001428:Bacterial Vaccines; D011994:Recombinant Proteins; D014614:Vaccines, Synthetic; D037521:Virulence Factors