[Construction and expression of spap/A eukaryotic expression plasmid of Streptococcus mutans in mammalian cells].

PURPOSE:The study is aimed to evaluate the expression of recombinant plasmid pVAX1-spap/A of surface protein antigen A of Streptococcus mutans in mammalian cells COS-7.METHODS:The eukaryotic plasmid carrying encoding gene of spap/A of Streptococcus mutans was constructed and the plasmid introduced into COS-7 cells by lipofectamine reagent.The transient expressed protein was detected by immunochemistry technique in COS-7 cells.RESULTS:Positive expression was detected in plasma of the cells which were transfected with recombinant plasmid pVAX1-spap/A.The cells which were transfected with pVAX1 were negative.CONCLUSIONS:Spap/A can translate and express in COS-7 cells after transfected with recombinant plasmid pVAX1-spap/A.The expressed protein locates in the plasma and the protein is able to combine with anti-spap/A antibody.The expressed protein has the antigenicity and recombinant plasmid pVAX1-spap/A is a candidate vaccine.