Systemic immune responses to oral administration of recombinant attenuated Salmonella typhimurium expressing Helicobacter pylori urease in mice.
OBJECTIVE
To evaluate whether attenuated Salmonella typhimurium producing Helicobacter pylori (H pylori) urease subunit B (UreB) could induce systemic immune responses against H pylori infection.


METHODS
Attenuated S. typhimurium SL3261 was used as a live carrier of plasmid pTC01-UreB, which encodes recombinant H pylori UreB protein. Balb/c mice were given oral immunization with two doses of SL3261/pTC01-UreB at a 3-wk interval. Twelve weeks after oral immunization of mice, serum IgG antibodies were evaluated by ELISA assay. Gamma interferon (IFN-gamma) and interleukin 10 (IL-10) in the supernatant of spleen cell culture were also assessed by ELISA.


RESULTS
After oral immunization of mice, serum specific IgG antibodies against UreB in vaccine group were much higher than that in PBS and native Salmonella SL3261 control groups (A450, 0.373+/-0.100 vs 0.053+/-0.022, 0.142+/-0.039, respectively, P<0.01). Moreover, IFN-gamma in vaccine group was on average 167.53+/-29.93 pg/mL, which showed a significant increase vs that of PBS control group (35.68+/-3.55 pg/mL, P<0.01). There was also a tremendous increase of IL-10 in vaccine group compared to PBS and SL3261 control groups (275.13+/-27.65 pg/mL vs 56.00+/-7.15 pg/mL, 68.02+/-15.03 pg/mL, respectively, P<0.01). In addition, no obvious side effects in mice and no change in gastric inflammation were observed.


CONCLUSIONS
The multiple oral immunizations with the attenuated S. typhimurium expressing H pylori UreB could induce significant systemic immune responses, suggesting it may be used as oral vaccine against H pylori infection.
Liu
Xiao-Feng
XF
Department of Gastroenterology, General Hospital of Jinan Military Command Area, Jinan 250031, Shandong Province, China. liuxf0531@21cn.com
Hu
Jia-Lu
JL
Quan
Qi-Zheng
QZ
Sun
Zi-Qin
ZQ
Wang
Yao-Jun
YJ
Qi
Feng
F
D000284:Administration, Oral; D000818:Animals; D001428:Bacterial Vaccines / Q000235:genetics / Q000276:immunology / Q000494:pharmacology*; D005260:Female; D016481:Helicobacter Infections / Q000276:immunology / Q000517:prevention & control*; D016480:Helicobacter pylori / Q000235:genetics* / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D012486:Salmonella typhimurium / Q000235:genetics*; D014510:Urease / Q000235:genetics / Q000276:immunology*; D014613:Vaccines, Attenuated / Q000235:genetics / Q000276:immunology / Q000494:pharmacology; D014614:Vaccines, Synthetic / Q000235:genetics / Q000276:immunology / Q000494:pharmacology
D001428:Bacterial Vaccines; D014613:Vaccines, Attenuated; D014614:Vaccines, Synthetic; D014510:Urease