Nasal immunization with E. coli verotoxin 1 (VT1)-B subunit and a nontoxic mutant of cholera toxin elicits serum neutralizing antibodies.
Escherichia coli O157:H7 produces two forms of verotoxin (VT), VT1 and VT2, which cause hemorrhagic colitis with development, in some cases, of hemolytic uremic syndrome. These toxins consist of an enzymatically active A subunit and pentamers of B subunit responsible for their binding to host cells. We used the secretion-expression system of Bacillus brevis to produce recombinant VT1B and VT2B. The secreted B subunits were purified and sequenced to verify their structure. Receptor-binding showed that rVT1B but not rVT2B bound to Gb3-receptor. When mice were nasally immunized with rVT1B or rVT2B together with a nontoxic mutant of cholera toxin (mCT) or native cholera toxin (nCT) as adjuvants, serum IgG and mucosal IgA antibody responses to VT1B were induced. The VT1B-specific antibodies prevented VT1B binding to its Gb3 receptor. In contrast, poor serum and no mucosal VT2B-specific antibodies but brisk CTB-specific antibody responses were induced by nasal immunization with rVT2B in the presence of mCT or nCT. These results show that nasal immunization with rVTB and mCT as a nontoxic mucosal adjuvant is an effective regimen for the induction of VT1B but not VT2B antibody responses which inhibit VT1B binding to Gb3 receptor.
Byun
Y
Y
JCR Biopharmaceuticals Incorporated, , San Diego, CA 92121-1194, USA.
Ohmura
M
M
Fujihashi
K
K
Yamamoto
S
S
McGhee
J R
JR
Udaka
S
S
Kiyono
H
H
Takeda
Y
Y
Kohsaka
T
T
Yuki
Y
Y
D000276:Adjuvants, Immunologic / Q000008:administration & dosage; D000281:Administration, Intranasal; D000595:Amino Acid Sequence; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood*; D001407:Bacillus / Q000235:genetics; D001428:Bacterial Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D001483:Base Sequence; D002772:Cholera Toxin / Q000008:administration & dosage* / Q000235:genetics / Q000633:toxicity; D017931:DNA Primers / Q000235:genetics; D019453:Escherichia coli O157 / Q000276:immunology; D005822:Genetic Vectors; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D009500:Neutralization Tests; D010957:Plasmids / Q000235:genetics; D021122:Protein Subunits; D022622:Shiga Toxin 1 / Q000008:administration & dosage* / Q000737:chemistry / Q000235:genetics; D022641:Shiga Toxin 2 / Q000008:administration & dosage / Q000235:genetics; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology
D000276:Adjuvants, Immunologic; D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines; D017931:DNA Primers; D021122:Protein Subunits; D022622:Shiga Toxin 1; D022641:Shiga Toxin 2; D014614:Vaccines, Synthetic; D002772:Cholera Toxin