Table 2.

Selection and amplification efficiency of different vectors

Vector	-HT Selection efficiency (%) 1	10 nM MTX Amplification efficiency (%) 2	50 nM MTX Amplification efficiency (%) 2
pAID	100	87	73
pAIDp	97	77	40
pAIDpp	70	40	10
pAI709Dp	0	0	0
pAI772Dp	86	90	13
pAID*	84	100	23
pAID*p	45	7	3
Untransfected control	0	0	0

¹Total number of cell pools subjected to –HT selection is 96.

²30 cell pools that survived –HT selection were randomly selected for sequential MTX amplification at 10 nM followed by 50 nM. Amplification efficiency is calculated as the percentage of cell pools out of the 30 initial cell pools that survived the amplification process.