Based on interdisciplinary research, The Protein engineering platform of Recbio uses a structure-based approach to immunogen design to provide antigen optimization solutions for innovative vaccine development. The platform enables rapid discovery and identification of potential antigens to determine the structural basis of antigenicity, understand the mechanisms of immune protection and guide rational immunogen design, which is a key step for the company to develop vaccines. In addition, the company's protein engineering platform uses a variety of expression systems, including E. coli, Hanson's yeast, baculovirus and CHO cell expression systems. Through this diverse expression approach, the company is able to select and apply the most appropriate expression system for vaccine development. The platform enables the company to rapidly advance the development of vaccine candidates for COVID-19 and HPV.