Recombinant Bacillus subtilis spores expressing cholera toxin B subunit and Helicobacter pylori urease B confer protection against H. pylori in mice

J Med Microbiol. 2017 Jan;66(1):83-89. doi: 10.1099/jmm.0.000404. Epub 2017 Feb 22.

Abstract

Helicobacter pylori infection is associated with chronic gastritis, peptic ulcers, gastric cancer and mucosa-associated lymphoid tissue lymphoma. The limitations of current therapies for H. pylori infection include poor compliance and antibiotic resistance. Therefore, an effective anti-H. pylori vaccine would be an alternative or complement to antibiotic treatment. Urease B (UreB) is considered an ideal vaccine antigen against H. pylori infection. In this study, cholera toxin B subunit (CTB), a mucosal adjuvant, was used to enhance the immunogenicity of a novel Bacillus subtilis spore vaccine expressing CTB-UreB, along with the B. subtilis spore coat protein CotC as a fusion protein. Oral administration of B. subtilis spores expressing CotC-UreB or CotC-CTB-UreB led to increased levels of UreB-specific IgG in serum and UreB-specific IgA in faeces, as well as elevated levels of IL-10 and IFN-γ in splenocytes. In addition, oral administration of CotC-UreB or CotC-CTB-UreB spores induced significant reductions (80.0 and 90.5 %, respectively) in gastric H. pylori bacterial load (1.11±0.36×105 and 0.53±0.21×105 c.f.u., respectively) compared to that of the CotC control group (5.56±1.64×105 c.f.u., P<0.01). Moreover, CotC-CTB-UreB spores were significantly more effective at reducing the bacterial load than CotC-UreB spores (P<0.05). These results indicate that CotC-CTB-UreB-expressing B. subtilis spores are a potential vaccine candidate for the control of H. pylori infection.

MeSH terms

  • Animals
  • Antibodies, Bacterial / immunology
  • Bacillus subtilis / immunology*
  • Bacterial Load
  • Bacterial Proteins / genetics
  • Bacterial Proteins / immunology*
  • Bacterial Vaccines / immunology
  • Cholera Toxin / genetics
  • Cholera Toxin / immunology*
  • Cloning, Molecular
  • DNA, Bacterial / genetics
  • Female
  • Helicobacter Infections / immunology
  • Helicobacter Infections / prevention & control*
  • Helicobacter pylori / enzymology*
  • Helicobacter pylori / immunology
  • Immunoglobulin A / immunology
  • Immunoglobulin G / immunology
  • Interferon-gamma / immunology
  • Interleukin-10 / immunology
  • Mice
  • Mice, Inbred BALB C
  • Recombinant Proteins / genetics
  • Recombinant Proteins / immunology
  • Spleen / cytology
  • Spleen / immunology
  • Spores, Bacterial / immunology
  • Urease / genetics
  • Urease / immunology*

Substances

  • Antibodies, Bacterial
  • Bacterial Proteins
  • Bacterial Vaccines
  • DNA, Bacterial
  • Immunoglobulin A
  • Immunoglobulin G
  • Recombinant Proteins
  • Interleukin-10
  • Interferon-gamma
  • Cholera Toxin
  • Urease