Production of SARS-CoV-2 Subunit Vaccine in Pichia pastoris
Lead supervisor: Prof Alain Townsend & Dr Tiong Kit Tan, Radcliffe Department of Medicine
Commercial partner: Ingenza, Edinburgh
COVID-19, caused by the SARS-CoV-2 coronavirus has spread throughout the world and was declared a pandemic by the WHO in March 2020. There are no effective vaccines nor treatments available to date. A safe and effective vaccine is the key to ending the COVID-19 pandemic. We have been developing a protein subunit vaccine based on the novel SpyTag/SpyCatcher technology to display the SARS-CoV-2 RBD (receptor binding domain) on a virus-like particle (VLP) to create a potent vaccine (RBD-SpyVLP). Preliminary results show that the vaccine is highly immunogenic and induces strong neutralising antibody response in two different animal models (Tan et.al., 2020).
Using Ingenza’s proprietary cGMP compliant Pichia pastoris production system, we are aiming to evaluate and optimise production of the RBD-SpyVLP vaccine using a recombinant Pichia host and a readily scalable fermentation process, which is highly productive, cost-effective and time saving both in batch manufacturing and its future adaptability to produce RBD variants or other vaccine targets. The project will involve optimisation of RBD production in P. pastoris through optimisation of i) the RBD sequences, ii) DNA sequences regulating recombinant gene expression in Pichia and heterologous protein secretion, iii) removable fluorescent protein fusions that assist selection of the most productive Pichia strains and simplify downstream purification of RBD produced in Pichia. The second part of the project involves production of RBD-SpyVLP using RBD recovered from Pichia cultures, in vitro validation and antigenicity characterisation of conjugated RBD-VLP, structural study of the RBD-VLP using CryoEM or TEM followed by in vivo immunisation and immunogenicity studies.