Antibiotic-free production of a herpes simplex virus 2 DNA vaccine in a high yield cGMP process

Two DNA vaccine plasmids encoding Herpes simplex virus type 2 (HSV-2) glycoprotein D, NTC8485-O2-gD2 and NTC8485-O2-UgD2tr, were produced at large scale under current good manufacturing practice (cGMP) for use in a Phase I human clinical trial. These DNA vaccines incorporate the regulatory agency compliant, minimal, antibiotic-free (AF) NTC8485 mammalian expression vector. Plasmid yields of>1 g/L were achieved using the HyperGRO™ fed-batch fermentation process, with successful scale up from 10 L process development scale to 320 L culture volume for cGMP production. The DNA vaccines were purified using a low residence time, high shear lysis process and AIRMIX(TM) technology, followed by chromatographic purification. This combination of optimized plasmid vector, high yield upstream production, and efficient downstream purification resulted in purified HSV-2 DNA vaccines with>99% total supercoiled plasmid, ≤ 0.2% RNA, ≤ 0.1% host cell genomic DNA, and ≤ 0.1 endotoxin units per mg.