Serological response to Helicobacter pylori recombinant antigens in Chilean infected patients with duodenal ulcer, non‐ulcer dyspepsia and gastric cancer

Abstract

A. Serological response to Helicobacter pylori recombinant antigens in Chilean infected patients with duodenal ulcer, non-ulcer dyspepsia and gastric cancer. APMIS 1999; 107: 1069-78.We have previously cloned 10 Helicobacter pylori antigen genes from a Chilean strain including: cytotoxin VacA, a truncated region of CagA (called A17), a species-specific protein (Ag26), urease subunits (UreA, UreB), a flagellin, (FlaB), heat shock proteins (HspA and HspB), an adhesin (HpaA) and a lipoprotein (Lpp20). Immunogenicity of these antigens was tested by immunoblot with sera of Chilean infected patients, revealing that HpaA, A17, HspB and VacA were more frequently recognized (86'%), 82%, 68% and 68%, respectively). According to the clinical condition, it was determined that Lpp20 was preferentially recognized by sera from non-ulcer dyspepsia patients (80%), A1 7 and VacA by patients with duodenal ulcer (92% and 83%) respectively), and HspB by patients with duodenal ulcer (83'X)) and gastric cancer (90%). An ELISA was developed with a purified mixture of A17 and VacA antigens to test the different groups of patients. It was found that sera from duodenal ulcer patients showed higher values than those from non-ulcer dyspepsia patients, but this difference was not significant (pc0.2). Moreover, sera from gastric cancer patients showed values lower than those from non-ulcer dyspepsia patients (p<0.019). These results indicate that, in the Chilean population, antibodies raised against VacA and A17 are not markers either for duodenal ulcer or for gastric cancer.

Construction of expression systems forflaAandflaBgenes ofHelicobacter pyloriand determination of immunoreactivity and antigenicity of recombinant proteins

“…The FlaA and FlaB expressed by H pylori rendered the organism strong motility in mucous environment, induced IL-8 secretion and facilitated inflammation in gastric tissue [51,52] . Furthermore, we observed that serum antibodies against FlaA and FlaB were present in approximate 98.4 % and 92.8 % of H pylori infected patients, respectively, the rates were significantly higher than those of heat shock protein (68 %) and vacuolating cytotoxin (68 %) [60] . These data indicate that flaA and flaB genes express their products in majority of H pylori strains and efficiently induce specific antibodies, implying a brilliant potential for developing H pylori vaccine.…”

Construction of hpaA gene from a clinical isolate ofHelicobacter pyloriand identification of fusion protein

“…HpaA gene is located in genome DNA of H.pylori and considerably conservative for its nucleotide and amino acid sequences [55,56] . Furthermore, antibody against HpaA could be found in approximately 86 % of H.pylori infected patients' sera and this proportion was obviously higher than that of heat shock protein (68 %) and vacuolating cytotoxin (68 %) [57] and was similar to that of urease B [64] . Therefore, HpaA is an ideal antigen candidate for H.pylori vaccine.…”

“…The result of ELISA for an H.pylori ultrasonic supernatant was considered as positive if its OD 490 value was over the mean plus 3 SD of 6 cases of ultrasonic supernatant at the same protein concentration of E.coli ATCC 25922 played as negative control [54] . Data analysis The nucleotide sequences of the cloned hpaA gene inserted in the two recombinant plasmid vectors were compared for homologies with 6 published hpaA gene sequences (X92502, NC000915, X61574, NC000921, AF479028 and U35455) [51,53,[55][56][57][58] with a special molecular biological analysis soft ware.…”

“…The hpaA gene nucleotide sequences in the recombinant plasmid vectors of pUCm-T-hpaA and pET32a-hpaA were completely the same. The homologies of the nucleotide and putative amino acid sequences in the pUCm-T-hpaA and pET32a-hpaA compared with the published hpaA gene sequences [51,53,[55][56][57][58] were from 94. 25-97.32 % and 95.38-98.46 %, respectively (Figures 2, 3).…”

Novel Antigens of Helicobacter pylori Correspond to Ulcer-Related Antibody Pattern of Sera from Infected Patients

“…Some reports provide evidence for the usefulness of the immunoblotting diagnosis of GDU in Brazilian children (25). Other authors claim that there is no association of specific H. pylori antigens with antibodies in adult patients suffering from various gastroduodenal pathologies in Germany (14) and Chile (20). Apparently, these contradictory findings reflect both the phenotypic heterogeneity of H. pylori and the specificity of the host immune response within various populations.…”