Comparison of expression of recombinant binding region (RBD) of SARS-CoV-2 virus in Escherichia coli and insect cells, evaluation of recombinant protein function with patient serum

COVID-19, an infectious viral disease caused by severe acute respiratory syndrome (SARS-CoV-2) with more than 260 million infections as of December 2019, is a serious threat to the health and economy of human societies. Designing and producing a suitable vaccine can Reduce the incidence of this disease. Therefore, it is very important to find effective and safe neutralizing antibodies and vaccines for COVID-19. The RDB section of the spike protein is a suitable option for the production of subunit vaccines and neutralizing antibodies. This research aims to introduce the RBD section as a vaccine candidate.

The RBD was recombinantly expressed in two hosts, Escherichia coli (E.coli) and insect cells, and its production rate was compared. Using the western blotting method, protein production was confirmed. To evaluate the function of the protein expressed in two prokaryotic and eukaryotic hosts, using the serum of patients recovered from COVID-19 (wild type and delta), the ELISA method was used.

Despite the higher production of recombinant protein by E.coli, the affinity of the antibodies in the serum of the patients to the protein expressed in the insect cell was higher.

In this study, the RBD was expressed in two different hosts. The results show that RBD is mentioned as a vaccine candidate. Homozygous in the insect cell preserves the biological activity of the protein by carrying out the process of post-translational changes such as glycosylation.