title: Induction of a humoral immune response to a Shiga toxin B subunit epitope expressed as a chimeric LamB protein in a Shigella flexneri live vaccine strain.
abstract: Shigella flexneri vaccine strain (SFL124) given orally, evokes humoral immune response in human volunteers. Such a strain, expressing antigenic epitope of B subunit of Shiga toxin, would also provide immunity to the toxin produced by some species of Shigella. A synthetic oligonucleotide, specifying an epitope [13-26 amino acids (aa)] of the B subunit of Shiga toxin, was inserted into the lamB gene of Escherichia coli and expressed in the S. flexneri vaccine strain. The chimeric LamB protein functioned normally and the epitope was expressed at the surface of the bacteria. The animals immunized with the live bacteria, expressing the epitope or sonicated lysates, showed a humoral response that was specific to the peptide (13-26 aa) and to the whole B subunit molecule. The elicited antisera neutralized the toxin activity on HeLa cells up to 40%, while the purified IgG fractions from the sera gave 90% neutralization.
authors.affiliation: Karolinska Institute, Department of Clinical Bacteriology, Huddinge, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Ryd
authors.forename: N
authors.initials: N
authors.lastname: Verma
authors.forename: A A
authors.initials: AA
authors.lastname: Lindberg
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000907:Antibodies, Bacterial / Q000096:biosynthesis; D000942:Antigens, Bacterial / Q000276:immunology*; D001425:Bacterial Outer Membrane Proteins; D001427:Bacterial Toxins / Q000235:genetics / Q000276:immunology*; D001483:Base Sequence; D000939:Epitopes / Q000235:genetics / Q000276:immunology*; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000276:immunology; D018272:Porins; D011817:Rabbits; D011991:Receptors, Virus / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology; D022603:Shiga Toxins; D012763:Shigella flexneri / Q000235:genetics / Q000276:immunology*; D014613:Vaccines, Attenuated / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001427:Bacterial Toxins; D000939:Epitopes; D010446:Peptide Fragments; D018272:Porins; D011991:Receptors, Virus; D011993:Recombinant Fusion Proteins; D022603:Shiga Toxins; D014613:Vaccines, Attenuated; C016532:maltoporins