Immunogenicity of the B monomer of Escherichia coli heat-labile toxin expressed on the surface of Streptococcus gordonii.
The B monomer of the Escherichia coli heat-labile toxin (LTB) was expressed on the surface of the human oral commensal bacterium Streptococcus gordonii. Recombinant bacteria expressing LTB were used to immunize BALB/c mice subcutaneously and intragastrically. The LTB monomer expressed on the streptococcal surface proved to be highly immunogenic, as LTB-specific immunoglobulin G (IgG) serum titers of 140,000 were induced after systemic immunization. Most significantly, these antibodies were capable of neutralizing the enterotoxin in a cell neutralization assay. Following mucosal delivery, antigen-specific IgA antibodies were found in feces and antigen-specific IgG antibodies were found in sera. Analysis of serum IgG subclasses showed a clear predominance of IgG1 when recombinant bacteria were inoculated subcutaneously, while a prevalence of IgG2a was observed upon intragastric delivery, suggesting, in this case, the recruitment of a Th1 type of immune response.
Ricci
S
S
Dipartimento di Biologia Molecolare, Sezione di Microbiologia, Università di Siena, 53100 Siena, Italy.
Medaglini
D
D
Rush
C M
CM
Marcello
A
A
Peppoloni
S
S
Manganelli
R
R
Palú
G
G
Pozzi
G
G
D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D001427:Bacterial Toxins / Q000276:immunology*; D004768:Enterotoxins / Q000276:immunology*; D004926:Escherichia coli / Q000276:immunology*; D029968:Escherichia coli Proteins; D005260:Female; D006801:Humans; D007114:Immunization; D007074:Immunoglobulin G / Q000097:blood; D051379:Mice; D008807:Mice, Inbred BALB C; D009856:Oncogene Proteins, Viral / Q000276:immunology; D050725:Papillomavirus E7 Proteins; D011994:Recombinant Proteins / Q000276:immunology; D013291:Streptococcus / Q000235:genetics / Q000276:immunology*
D000907:Antibodies, Bacterial; D001427:Bacterial Toxins; D004768:Enterotoxins; D029968:Escherichia coli Proteins; D007074:Immunoglobulin G; D009856:Oncogene Proteins, Viral; D050725:Papillomavirus E7 Proteins; D011994:Recombinant Proteins; C059731:oncogene protein E7, Human papillomavirus type 16; C027538:heat-labile enterotoxin, E coli