In Vitro Stability of Botulinum Neurotoxin Serotypes A and B Recombinant Light Chains in Human Serum, Buffered Solutions, Water and Milk
Abstract
Symptoms of botulinum neurotoxin (BoNT) intoxication can persist for many months presumably due to the intracellular stability of the BoNT light chain (LC). LC catalytic activity is highly stable in vivo (>11 weeks for serotype A, 6-8 weeks for serotype B) (1-3). In the present study, we determined stability of recombinant BoNT LC (rLC) serotypes A and B in HEPES buffer, intracellular buffer (ICB), bottled water, human serum and milk. BoNT/A and BoNT/B rLCs were incubated in test solutions at 4 deg C, 22 deg C or 37 deg C for up to 6 months. Stability was assessed by monitoring catalytic activity using a fluorescent microplate assay (4). BoNT rLCs were most stable in ICB and least stable in human serum. Regardless of solution, a graded decrease in stability occurred between 4 deg C and 22 deg C, whereas a striking reduction was observed from 22 deg C to 37 deg C. The relative instability of the rLC at 37 deg C in the test solutions is in marked contrast to the unusually high in vivo stability of the LCs. Stability in milk increased with increasing milkfat for the BoNT/A rLC, but not for the BoNT/B rLC, suggesting a greater role of lipids in the stability of the former. The results indicate that the factors regulating the stability of BoNT LCs may be serotype specific and factors relating to localization or trafficking of the LCs may contribute to their stability.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 31, 2020
- Accession Number
- AD1108970
Entities
People
- Heidi Hoard-fruchey
- Michael Adler
Organizations
- United States Army Medical Research Institute of Chemical Defense