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Holistic process development to mitigate proteolysis of a subunit rotavirus vaccine candidate produced in Pichia pastoris by means of an acid pH pulse during fed-batch fermentation.

Published version
Peer-reviewed

Type

Article

Change log

Authors

Velez-Suberbie, M Lourdes  ORCID logo  https://orcid.org/0000-0002-1980-0687
Morris, Stephen A 
Kaur, Kawaljit 
Hickey, John M 
Joshi, Sangeeta B 

Abstract

To meet the challenges of global health, vaccine design and development must be reconsidered to achieve cost of goods as low as 15¢ per dose. A new recombinant protein-based rotavirus vaccine candidate derived from non-replicative viral subunits fused to a P2 tetanus toxoid CD4(+) T cell epitope is currently under clinical development. We have sought to simplify the existing manufacturing process to meet these aims. To this end, we have taken a holistic process development approach to reduce process complexity and costs while producing a product with the required characteristics. We have changed expression system from Escherichia coli to Pichia pastoris, to produce a secreted product, thereby reducing the number of purification steps. However, the presence of proteases poses challenges to product quality. To understand the effect of fermentation parameters on product quality small-scale fermentations were carried out. Media pH and fermentation duration had the greatest impact on the proportion of full-length product. A novel acidic pH pulse strategy was used to minimize proteolysis, and this combined with an early harvest time significantly increased the proportion of full-length material (60-75%). An improved downstream process using a combination of CIEX and AIEX to further reduce proteases, resulted in maintaining product quality (95% yield).

Description

Keywords

Pichia pastoris, fed-batch fermentation, ion exchange chromatography, proteolysis, vaccine development, Batch Cell Culture Techniques, Fermentation, Humans, Hydrogen-Ion Concentration, Proteolysis, Rotavirus, Rotavirus Infections, Rotavirus Vaccines, Saccharomycetales

Journal Title

Biotechnol Prog

Conference Name

Journal ISSN

8756-7938
1520-6033

Volume Title

36

Publisher

Wiley