The development of yeast strains to produce SARS-CoV-2 antigens for serological assays enabling the detection of COVID-19 cases in the UK population

Phenotypeca Ltd is a biotechnology company based in the University of Nottingham's Synthetic Biology Research Centre developing next-generation yeast for the manufacture of recombinant proteins, such as biopharmaceuticals.

Using a genetically diverse collection of natural baker's yeast engineered for large-scale industrial processes we breed up to a billion progeny and select cells optimised for the product and process of choice. Baker's yeast has been safely used for over 30-years for the bulk manufacture of biologics, such as insulin and vaccines, and is relatively inexpensive compared to mammalian systems.

This project aims to address an urgent unmet need for SARS-CoV-2 viral antigens for the UK's production of serological assays, used to identify individuals with immunity to COVID-19\. Phenotypeca will produce yeast strains for the manufacture of specific antigens for evaluation by Oxford University's Jenner Institute, and build UK partnerships for their supply to serological assay producers.

Parts of the SARS-CoV-2 virion have strong homology to other coronaviruses, making it challenging to produce tests that are both specific (no false positives, risking COVID-19 spreading) and sensitive (no false negatives, preventing people with immunity from returning to normal activities). To achieve this, we have designed multiple antigens from unique parts of the virus particle's structural proteins, including an exposed region known to bind the human ACE2 receptor, which has been guided by previous work that successfully made high-quality antigens from yeast after the 2003 coronavirus outbreak. We aim to develop yeast strains for the secretion of these antigens to simplify purification and manufacture.