title: Characterization of the antibody response to the receptor binding domain of botulinum neurotoxin serotypes A and E.
abstract: Clostridium botulinum neurotoxins (BoNTs) are the most toxic proteins for humans. The current clostridial-derived vaccines against BoNT intoxication have limitations including production and accessibility. Conditions were established to express the soluble receptor binding domain (heavy-chain receptor [HCR]) of BoNT serotypes A and E in Escherichia coli. Sera isolated from mice and rabbits immunized with recombinant HCR/A1 (rHCR/A1) from the classical type A-Hall strain (ATCC 3502) (BoNT/A1) and rHCR/E from BoNT serotype E Beluga (BoNT/E(B)) neutralized the homologous serotype of BoNT but displayed differences in cross-recognition and cross-protection. Enzyme-linked immunosorbent assay and Western blotting showed that alpha-rHCR/A1 recognized epitopes within the C terminus of the HCR/A and HCR/E, while alpha-rHCR/E recognized epitopes within the N terminus or interface between the N and C termini of the HCR proteins. alpha-rHCR/E(B) sera possessed detectable neutralizing capacity for BoNT/A1, while alpha-rHCR/A1 did not neutralize BoNT/E. rHCR/A was an effective immunogen against BoNT/A1 and the Kyoto F infant strain (BoNT/A2), but not BoNT serotype E Alaska (BoNT/E(A)), while rHCR/E(B) neutralized BoNT/E(A), and under hyperimmunization conditions protected against BoNT/A1 and BoNT/A2. The protection elicited by rHCR/A1 to BoNT/A1 and BoNT/A2 and by rHCR/E(B) to BoNT/E(A) indicate that immunization with receptor binding domains elicit protection within sub-serotypes of BoNT. The protection elicited by hyperimmunization with rHCR/E against BoNT/A suggests the presence of common neutralizing epitopes between the serotypes E and A. These results show that a receptor binding domain subunit vaccine protects against serotype variants of BoNTs.
authors.affiliation: Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, Milwaukee, 53226, USA.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Baldwin
authors.forename: William H
authors.initials: WH
authors.lastname: Tepp
authors.forename: Christina L
authors.initials: CL
authors.lastname: Pier
authors.forename: Marite
authors.initials: M
authors.lastname: Bradshaw
authors.forename: Mengfei
authors.initials: M
authors.lastname: Ho
authors.forename: Brenda A
authors.initials: BA
authors.lastname: Wilson
authors.forename: Robert B
authors.initials: RB
authors.lastname: Fritz
authors.forename: Eric A
authors.initials: EA
authors.lastname: Johnson
authors.forename: Joseph T
authors.initials: JT
authors.lastname: Barbieri
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood / Q000276:immunology* / Q000494:pharmacology; D001428:Bacterial Vaccines / Q000737:chemistry / Q000276:immunology*; D001905:Botulinum Toxins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000276:immunology*; D019274:Botulinum Toxins, Type A / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D003014:Clostridium botulinum / Q000276:immunology*; D004926:Escherichia coli / Q000235:genetics; D051379:Mice; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000235:genetics / Q000276:immunology*; D011487:Protein Conformation; D011817:Rabbits
chemical_list: D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines; D010446:Peptide Fragments; C505469:botulinum neurotoxin A (844-1250); C505468:botulinum neurotoxin A (870-1295); D001905:Botulinum Toxins; D019274:Botulinum Toxins, Type A; C096326:botulinum toxin type E