Antigenicity and Immunogenicity of Sars-Cov-2 Surface Glycoprotein Fragment in Cho Cells

Background and objectives: severe acute respiratory syndrome coronavirus 2 (sars-cov-2) spike (s) glycoprotein that projects from the virus surface is highly immunogenic. it is considered to be the target of many neutralizing antibodies as well as a target in vaccine design efforts. evaluation the immunogenicity of a recombinant fragment of the spike protein (rfsp) that is comprised of receptor binding domain (rbd), s1/s2 cleavage site, and fusion peptide (fp) as immunogenic proteins of sars-cov-2, in balb/c mice and evaluation of the efficacy of epitopes rfsp as a multi-subunit chimeric vaccine. materials and methods: the present study made use of cho-k1 (chinese hamster ovary k1) cells to create a cell line for constant expression rfsp. the rfsp was purified with ni-nta chromatography and confirmed by western blotting. the immunogenicity and neutralizing antibody efficacy of rfsp were evaluated in balb/c mice. elisa was employed to test rfsp via sera of covid-19 convalescent patients infected with sars-cov-2 alpha and delta variants. results: our results showed significant differences in antibody titers in immunized mice compared to the control groups and neutralizing antibodies were positive, sera from mice immunized are capable of bound sars-cov-2 virus, chimer peptide is capable bound antibodies patients infected with sars-cov-2 and patients infected with delta variant sars-cov-2. conclusion: overall, these results indicate that rfsp protein would be a novel potential antigen candidate for the development of a subunit sars cov-2 vaccine and rfsp has the potential to be a useful option for the development of the assays for serodiagnosis of sars-cov-2 infection.