• Journal of Microbiology and Biotechnology
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• v.29 no.7
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• pp.1165-1176
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• 2019

Botulinum neurotoxins (BoNTs), produced by Clostridium botulinum, are the most toxic substances known. However, the number of currently approved medical countermeasures for these toxins is very limited. Therefore, studies on therapeutic antitoxins are essential to prepare for toxin-related emergencies. Currently, more than 10,000 Halla horses, a crossbreed between the native Jeju and Thoroughbred horses, are being raised in Jeju Island of Korea. They can be used for equine antitoxin experiments and production of hyperimmune serum against BoNT/A1. Instead of the inactivated BoNT/A1 toxoid, Halla horse was immunized with the receptor-binding domain present in the C-terminus of heavy chain of BoNT/A1 (BoNT/A1-HCR) expressed in Escherichia coli. The anti-BoNT/A1-HCR antibody titer increased rapidly by week 4, and this level was maintained for several weeks after boosting immunization. Notably, $20{\mu}l$ of the week-24 BoNT/A1-HCR(-immunized) equine serum showed an in vitro neutralizing activity of over 8 international units (IU) of a reference equine antitoxin. Furthermore, $20{\mu}l$ of equine serum and $100{\mu}g$ of purified equine $F(ab^{\prime})_2$ showed 100% neutralization of 10,000 $LD_{50}$ in vivo. The results of this study shall contribute towards optimizing antitoxin production for BoNT/A1, which is essential for emergency preparedness and response.

• YAKHAK HOEJI
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• v.44 no.4
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• pp.293-299
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• 2000

Biodegradable microspheres made from poly-lactide-co-glycolide polymers have been considered as a new delivery system for single-dose vaccine. Purified tetanus toxoid (TT) was encapsulated in poly-lactide(PLA) and poly-lactide-co-glycolide (PLGA) microparticles using a solvent evaporation method in a multiple emulsion system (water-in oil-in water). The morphology of 77-loaded microparticles was spherical and the suface of them was smooth. The particle size was in a range of 2-10. Protein loading efficiency was 68-97.8%. PLGA (85:15) microparticle showed the highest efficiency. Protein release pattern was influenced by polymer molecular weight and composition. The release rate of PLA(Mw 100,000) microsphere was higher than any other microspheres. In consequence of the hydrolysis of PLGA(50:50) microspheres, environmental pH decreased from 7.4 to 5.0. The PLA, PLGA (75:25) and PLGA (85:15) microshperes showed no significant pH change. The antigenicity or n in microshperes was assayed by indirect sandwich ELISA using equine polyclonal tetanus antitoxin for capture antibody and human polyclonal tetanus antitoxin for primary antibody. The antigenicity of TT in PLA (Mw 100,000), PLGA(50:50, Mw 100,000) and PLGA (75:25, Mw 73,300) after 30 days incubation showed 54, 40.9 and 76.7%, respectively.