(532b) Manufacturing and Design of a COVID-19 Vaccine Antigen for Global Access

To address the COVID-19 pandemic globally, the world will require >10 billion doses of vaccines for SARS-CoV-2. This requirement exceeds the annual capacity for manufacturing vaccines for all other diseases by >2x. Most of these doses are required in low- and middle-income countries (LMICs), where platforms for the manufacturing and distribution of vaccines are limited. To fulfill this need, it is clear that further innovations in vaccine design and manufacturing are required. Protein subunit vaccines are promising candidates for global distribution because they can be manufactured at low costs in microbial hosts. The yeast Komagataella phaffii (Pichia pastoris), for example, is commonly used to manufacture protein therapeutics at large scales (~10⁹ annual doses) in LMICs. We used K. phaffii to produce the SARS-CoV-2 spike protein receptor binding domain (RBD), a promising vaccine antigen found in many recent vaccine designs because of its small size and high density of neutralizing epitopes.

Here, we present a two-pronged approach of host-cell and protein engineering to improve global access to RBD-based vaccines. We genetically engineered K. phaffii to secrete the RBD without typical methanol-induction, which improved upstream titers ~5x and enabled longer production campaigns. We also rationally engineered an RBD protein with improved manufacturing titers and enhanced immunogenicity and antigenicity, enabling smaller dose sizes for wider vaccine distribution. The platform for RBD manufacturing presented here has been transferred to a GMP facility for manufacturing and clinical trials of engineering RBD antigens. This translational success suggests that the strain and protein engineering techniques presented here will be applicable to a wide range of protein therapeutics.