Expression and Immunogenicity Analysis of the Receptor-binding Region of SARS-CoV Spike Protein

In order to express the recombinant protein of SARS-CoV S receptor-binding region and to study its immunogenicity,the gene encoding SARS-CoV S receptor-binding region was cloned to pET32a+ and expressed in E.coli.The expression of the recombinant protein was confirmed by Western blot analysis.The S purified protein as diagnostic antigen coated the microtiter plates to detect 20 SARS sera and 28 healthy sera.The results showed that the S purified recombinant protein was able to react with all sera of SARS patients.BALB/c mice were immunized with the denatured and refolding protein respectively.Sera were collected after the third immunization for detection of neutralizing activity against SARS virus.The denatured recombinant S receptor-binding region protein could not induce neutralizing antibodies,whereas refolding recombinant S-RBD could elicit neutralizing antibodies.These results indicated that the receptor-binding region of the S protein could be used for vaccine development.