Table 2. Characterization of the recombinant viruses obtained by reverse genetics.

		4th passage		8th passage		11th passage
Constructa	Time of appearing CPEb	Retainedinsertc	Virus titerdTCID50/ml)	Retainedinsertc	Virus titerd(TCID50/ml)	Retainedinsertc	Virus titerd(TCID50/ml)
pOFS-HSV	48 h	yes	4×106	yes	5.6×107	yes	5×107
pOFS-FLAG	48 h	yes	2.7×106	yes	3.2×107	yes	3.4×107
pOFS	48 h	NDe	2.3×106	NDe	3.4×107	NDe	3×107

^aThree independent plasmid transfections were performed for each construct followed by passaging in BHK-21 cells.

^bTime (h) when CPE was detected after transfection.

^cThe tag inserts were determined by RT-PCR and sequencing analysis.

^dThe virus titer were determined on BHK-21 cells by calculating the 50% tissue culture infectious dose per ml (TCID₅₀/ml).

^eND: not done.