Large scale purification process for recombinant NS1-OspA as a candidate vaccine for Lyme disease

Abstract

A purification process was developed for the manufacture of NS1-OspA as a candidate vaccine for Lyme disease. NS1-OspA was expressed as a soluble recombinant protein in E. coli from 50 and 200 liter fermentations. A multistep bench scale procedure, including detergent treatment, sonication, Q-Sepharose chromatography, dialysis, and SP-Sepharose chromatography, was used to effectively purify NS1-OspA from E. coli to > 90% purity with a 35% yield. This procedure was subsequently modified and specific steps eliminated to create a manufacturing scale process for the purification of NS1-OspA. Continuous flow centrifugation, mechanical lysis, QA-52 anion exchange chromatography, acid induced precipitation, and cross flow filtration gave a final purity of > 75%, a recovery of > 70%, and measured endotoxin levels of < 5 micrograms/mg of protein. Unique features of this process include using unclarified lysates and a single use (disposable) resin for the batch chromatography step. This simple, cost effective production process provides a recombinant protein with the yield and purity suitable for use as a subunit veterinary vaccine.