title: Evaluating the immune responses of mice to subcutaneous immunization with Helicobacter pylori urease B subunit.
abstract: BACKGROUND
  Helicobacter pylori, a gram-negative bacterial pathogen that expresses a strong urease activity, is associated with the development of gastroduodenal disease. Urease B subunit, one of the two structural subunits of urease, was expressed in E. coli BL21 (DE3) strain. The objective of this study was to evaluate the effects of Helicobacter pylori urease B subunit on the immune responses in mice by subcutaneous immunization.
  
  
  METHODS
  The mice were immunized and boosted with Helicobacter pylori urease B subunit antigen subcutaneously three times with 2-wk intervals between the immunizations and boosters. The mice in the control group were immunized with PBS. The adjuvant group received PBS containing complete/incomplete freund's adjuvant identical to antigen group without Helicobacter pylori urease B subunit antigen. Four weeks after the final booster, all the mice were sacrificed. Blood was collected on d 0, 14, 28 and 56 before immunization, booster and sacrifice, respectively. Immediately after sacrifice, gastric liquid and spleen were collected for antibody and cytokine analyses.
  
  
  RESULTS
  Urease B subunit increased the concentrations of serum and gastric anti-urease B antigen specific IgG, and the levels of interleukin-4 and interferon-γ in splenocytes of the mice (P < 0.05).
  
  
  CONCLUSIONS
  This study demonstrated that recombinant urease B subunit can induce systemic and local immune responses in mice by subcutaneous immunization, which might be used as the effective component of vaccine against Helicobacter pylori.
authors.forename: Peng
authors.initials: P
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, No,2 Yuanmingyuan West Road, Beijing 100193, P, R, China. jqwangcaas@gmail.com.
authors.forename: Jia-Qi
authors.initials: JQ
authors.lastname: Wang
authors.forename: Yu-Tao
authors.initials: YT
authors.lastname: Zhang
authors.forename: Sheng-Guo
authors.initials: SG
authors.lastname: Zhao