Construction of rADV vector expressing SARS-CoV S glycoprotein and expression of S proteins in 293 T cells and bacteria. (A) The gene encoding codon-optimized SARS-S protein without helical regions, transmembrane domain and cytoplasmic domain was inserted into pShuttle vector to construct the rADV expressing the SARS-S protein. (B) 293 T cells were infected with rADV-S or rADV-EGFP and the S protein in the cell lysate was detected by Western blot. (C) DNA for SARS-S protein (amino acids 201–510) was inserted into pET15b vector to express recombinant S protein from E. coli. The protein was purified by His-tag affinity chromatography and detected by Western blot.