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Given the global epidemic of COVID-19, it is important to design a vaccine for prevention. The virus belongs to the beta-coronavirus family and forms appendages on the surface of the glycoprotein spike virus membrane. Studies on SARS-CoV-1 and related MERS-CoV vaccines have shown that the spike protein on the virus surface is a suitable target for the vaccine. In this experimental study, we compare the recombinant fragment of spike protein (rfsp) expressed in the eukaryotic host CHO-K1 cell and prokaryotic  E. coli in terms of immunogenicity, neutralizing activity, and epitopes recognition Similar to the virus strain and the ability to bind to the serum of improved patients, in two types of alpha and delta variants. The results showed that both rfSP proteins are a potential new antigen candidate for the development of the Covid 19 vaccine, but the CHO cell maintains the biological activity of the protein by performing post-translational modification processes such as glycolysis. This increases the present likelihood of developing virus-like epitopes and increases the titer of rfsp-specific antibodies in the serum of immunized mice. Therefore, priority is given to rfsp expressed in CHO cells to evaluate vaccine efficacy.