To detect the expression of product of recombinant protein PrP102-242 in COS-1 cells,purified recombinant protein of PrP102-242 were transfected into COS-1 cells,to obtain stable cell lines using different concentration of G418.After that,the expression of recombinant protein PrP102-242 in COS-1 were detected by using indirect immunity fluorescence assay(in-IFA),indirect enzyme linked immunosorbent assay(in-ELISA)and Western blot assay.The result showed that expression of pCIp264 in COS-1 were detected by using in-ELISA,IFA and Western blot.