Oral immunization of mice with lactic acid bacteria producing Helicobacter pylori urease B subunit partially protects against challenge with Helicobacter felis.
BACKGROUND
The development of an efficacious vaccine against infection with Helicobacter pylori, the causative agent of chronic gastritis, peptic ulcer disease, and gastric adenocarcinoma, remains a challenge. Since the use of mucosal adjuvants is limited in human application, we have evaluated the potential of recombinant Lactobacillus strains producing H. pylori urease B (UreB) subunit to deliver this antigen to the gastrointestinal tract.


METHODS
Mice were injected orally 3 times with a triple dose of recombinant Lactobacillus plantarum NCIMB8826, the recombinant isogenic cell-wall mutant (alr(-) MD007 strain) expressing UreB, or a mixture of recombinant UreB and cholera toxin (rUreB/CT) as a control. Urease-specific seric immunoglobulin (Ig) G and IgA were measured by use of an enzyme-linked immunosorbent assay. After challenge with Helicobacter felis, stomach infection was examined by use of the rapid urease test and by polymerase chain reaction detection of Helicobacter genomic DNA.


RESULTS
Intragastric immunization with both recombinant Lactobacillus strains and rUreB/CT elicited UreB-specific antibodies. After challenge, reduction of H. felis load in the stomachs of mice was observed only after immunization with the recombinant mutant strain MD007 or with rUreB/CT.


CONCLUSIONS
This is the first report of successful induction of partial protection against H. felis with a mucosal prime-boost regimen in which recombinant Lactobacillus strains were used as antigen-delivery vehicles.
Corthésy
Blaise
B
R and D Laboratory of the Division of Immunology and Allergy, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland.
Boris
Soledad
S
Isler
Patrick
P
Grangette
Corinne
C
Mercenier
Annick
A
D000276:Adjuvants, Immunologic; D000284:Administration, Oral; D000818:Animals; D000917:Antibody Formation; D001428:Bacterial Vaccines / Q000008:administration & dosage* / Q000276:immunology; D004195:Disease Models, Animal; D016998:Helicobacter / Q000302:isolation & purification; D016481:Helicobacter Infections / Q000276:immunology / Q000517:prevention & control*; D016480:Helicobacter pylori / Q000201:enzymology* / Q000235:genetics; D007071:Immunoglobulin A, Secretory / Q000096:biosynthesis* / Q000097:blood; D007074:Immunoglobulin G / Q000096:biosynthesis / Q000097:blood; D007778:Lactobacillus / Q000235:genetics / Q000276:immunology*; D051379:Mice; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000276:immunology; D014510:Urease / Q000008:administration & dosage* / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology
D000276:Adjuvants, Immunologic; D001428:Bacterial Vaccines; D007071:Immunoglobulin A, Secretory; D007074:Immunoglobulin G; D011994:Recombinant Proteins; D014510:Urease