Reduction of the ganglioside binding activity of the tetanus toxin HC fragment destroys immunogenicity: implications for development of novel tetanus vaccines.
In this study, the immunogenicities of the nontoxic H(C) fragment of tetanus toxin and derivatives lacking ganglioside binding activity were compared with that of tetanus toxoid after subcutaneous immunization of mice. Wild-type H(C) (H(C)WT) protein and tetanus toxoid both elicited strong antibody responses against toxoid and H(C) antigens and provided complete protection against toxin challenge. Mutants of H(C) containing deletions essential for ganglioside binding elicited lower responses than H(C)WT. H(C)M115, containing two amino acid substitutions within the ganglioside binding site, provided reduced protection against tetanus toxin challenge compared with H(C)WT, consistent with lower anti-H(C) and anti-toxoid antibody titers. Circular-dichroism spectroscopy and intrinsic fluorescence spectroscopy showed minimal structural perturbation in H(C)M115. We conclude that the presence of the ganglioside binding site within H(C) may be essential for induction of a fully protective anti-tetanus response comparable to that induced by tetanus toxoid by subcutaneous injection.
Qazi
Omar
O
Centre for Molecular Microbiology and Infection, Imperial College London, Flowers Building, South Kensington Campus, London SW7 2AZ, United Kingdom.
Sesardic
Dorothea
D
Tierney
Robert
R
Söderbäck
Zahra
Z
Crane
Dennis
D
Bolgiano
Barbara
B
Fairweather
Neil
N
D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood*; D005260:Female; D005732:Gangliosides / Q000378:metabolism*; D017353:Gene Deletion; D007114:Immunization; D051379:Mice; D010446:Peptide Fragments / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D013742:Tetanus / Q000517:prevention & control; D013744:Tetanus Toxin / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D013745:Tetanus Toxoid / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D014118:Toxins, Biological
D000907:Antibodies, Bacterial; D005732:Gangliosides; D010446:Peptide Fragments; D013744:Tetanus Toxin; D013745:Tetanus Toxoid; D014118:Toxins, Biological; C040635:tetanus toxin fragment C