Characterization of the antibody response to the receptor binding domain of botulinum neurotoxin serotypes A and E

Michael R. Baldwin, William H. Tepp, Christina L. Pier, Marite Bradshaw, Mengfei Ho, Brenda A. Wilson, Robert B. Fritz, Eric A. Johnson, Joseph T. Barbieri

Research output: Contribution to journalArticlepeer-review


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 α-rHCR/A1 recognized epitopes within the C terminus of the HCR/A and HCR/E, while α-rHCR/E recognized epitopes within the N terminus or interface between the N and C termini of the HCR proteins. α-rHCR/EB sera possessed detectable neutralizing capacity for BoNT/A1, while α-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/EB neutralized BoNT/EA, 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/EB to BoNT/EA 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.

Original languageEnglish (US)
Pages (from-to)6998-7005
Number of pages8
JournalInfection and immunity
Issue number10
StatePublished - Oct 2005

ASJC Scopus subject areas

  • Parasitology
  • Microbiology
  • Immunology
  • Infectious Diseases


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