Boosting systemic and secreted antibody responses in mice orally immunized with recombinant Bacillus subtilis strains following parenteral priming with a DNA vaccine encoding the enterotoxigenic Escherichia coli (ETEC) CFA/I fimbriae B subunit.
Recombinant Bacillus subtilis strains, either spores or vegetative cells, may be employed as safe and low cost orally delivered live vaccine vehicles. In this study, we report the use of an orally delivered B. subtilis vaccine strain to boost systemic and secreted antibody responses in mice i.m. primed with a DNA vaccine encoding the structural subunit (CfaB) of the CFA/I fimbriae encoded by enterotoxigenic Escherichia coli (ETEC), an important etiological agent of diarrhea among travelers and children living in endemic regions. DBA/2 female mice submitted to the prime-boost immunization regimen developed synergic serum (IgG) and mucosal (IgA) antibody responses to the target CfaB antigen. Moreover, in contrast to mice immunized only with one vaccine formulation, sera harvested from prime-boosted vaccinated individuals inhibited adhesion of ETEC cells to human red blood cells. Additionally, vaccinated dams conferred full passive protection to suckling newborn mice challenged with a virulent ETEC strain. Taken together the present results further demonstrate the potential use of recombinant B. subtilis strains as an alternative live vaccine vehicle.
Luiz
Wilson B
WB
Department of Microbiology, Biomedical Sciences Institute, University of São Paulo, São Paulo, Brazil.
Cavalcante
Rafael C M
RC
Paccez
Juliano D
JD
Souza
Renata D
RD
Sbrogio-Almeida
Maria E
ME
Ferreira
Rita C C
RC
Ferreira
Luís C S
LC
D000284:Administration, Oral; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood*; D001412:Bacillus subtilis / Q000235:genetics / Q000276:immunology*; D001428:Bacterial Vaccines / Q000276:immunology*; D016503:Drug Delivery Systems; D054307:Enterotoxigenic Escherichia coli / Q000235:genetics / Q000276:immunology*; D005260:Female; D036781:Fimbriae Proteins / Q000235:genetics / Q000276:immunology*; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D007114:Immunization; D007263:Infusions, Parenteral; D051379:Mice; D008811:Mice, Inbred DBA; D011401:Promoter Regions, Genetic / Q000235:genetics; D011994:Recombinant Proteins / Q000276:immunology; D016019:Survival Analysis; D019444:Vaccines, DNA / Q000008:administration & dosage / Q000276:immunology*
D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines; D011994:Recombinant Proteins; D019444:Vaccines, DNA; C022924:colonization factor antigens; D036781:Fimbriae Proteins