Construction of conditionally replicating adenovirus expressing staphylococcal enterotoxin A gene: potential usefulness for anti-tumor therapies.

OBJECTIVE The aim of this study was to construct a conditionally replicating adenovirus pPE3-SEA expressing staphylococcal enterotoxin A (SEA) gene. MATERIALS AND METHODS A full-length SEA gene fragment was cloned into pENTR12 plasmid to obtain a recombinant viral plasmid pENTR12-SEA. The pENTR12-SEA plasmid was co-transfected into HEK293 cells along with pPE3-ccdB, which encoded for the virus backbone, to generate recombinant adenovirus pPE3-SEA vector. Amplified pPE3-SEA vectors were purified, and viral titer was determined using the 50% tissue culture infective dose method. RESULTS The PCR, restriction enzyme digestion, and sequence analyses proved successful construction of replicating oncolytic adenovirus pENTR12-SEA and recombinant SEA expressing oncolytic adenovirus pPE3-SEA. The viral titer was 2.5 × 1010 pfu/ml. CONCLUSIONS We successfully constructed conditionally replicating adenovirus pPE3-SEA which can be utilized for experimental studies of tumor-targeted therapies.