Antigenic sites on the HN domain of botulinum neurotoxin A stimulate protective antibody responses against active toxin.
Botulinum neurotoxins (BoNTs) are the most toxic substances known. BoNT intoxicates cells in a highly programmed fashion initiated by binding to the cell surface, internalization and enzymatic cleavage of substrate, thus, inhibiting synaptic exocytosis. Over the past two decades, immunological significance of BoNT/A C-terminal heavy chain (HC) and light chain (LC) domains were investigated extensively leading to important findings. In the current work, we explored the significance of BoNT/A heavy chain N-terminal (HN) region as a vaccine candidate. Mice were immunized with recombinant HN519-845 generating antibodies (Abs) that were found to be protective against lethal dose of BoNT/A. Immuno-dominant regions of HN519-845 were identified and individually investigated for antibody response along with synthetic peptides within those regions, using in vivo protection assays against BoNT/A. Results were confirmed by patch-clamp analysis where anti-HN antibodies were studied for the ability to block toxin-induced channel formation. This data strongly indicated that HN519-593 is an important region in generating protective antibodies and should be valuable in a vaccine design. These results are the first to describe and dissect the protective activity of the BoNT/A HN domain.
Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030, USA.
B Vijayalakshmi
BV
Ayyar
Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas 77030, USA.
Rajeev B
RB
Tajhya
Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas 77030, USA.
Christine
C
Beeton
Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030, USA.|Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas 77030, USA.
M Zouhair
MZ
Atassi
D000595:Amino Acid Sequence / Q000502:physiology; D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology*; D000917:Antibody Formation / Q000276:immunology*; D019274:Botulinum Toxins, Type A / Q000276:immunology*; D007114:Immunization / Q000379:methods; D051379:Mice; D009498:Neurotoxins / Q000276:immunology*; D010446:Peptide Fragments / Q000276:immunology; D010455:Peptides / Q000276:immunology; D011485:Protein Binding / Q000276:immunology; D014118:Toxins, Biological / Q000276:immunology*; D014611:Vaccination / Q000379:methods
D000907:Antibodies, Bacterial; D009498:Neurotoxins; D010446:Peptide Fragments; D010455:Peptides; D014118:Toxins, Biological; D019274:Botulinum Toxins, Type A