TABLE 2.

Transduction using the virus produced by PG13 cells transduced with MSN or MSNΔ17^a

Vector	Relative CAT activity			Viral titer (105)
	Producer line	Transduction
		Transient	Stable
MSN	100	100	100	3.2 ± 1.5
MSNΔ17	83 ± 6	7.1 ± 2.7	85 ± 10	0.14 ± 0.06

^aCell-free viral supernatants were prepared as described in Table 1 and were used to transduce the PG13 line (13) at the same low MOI, around 0.1. All other procedures were identical to those described in Table 1 except that HT1080 cells, instead of NIH 3T3 cells, were used as target cells, as they are prone to viruses pseudotyped with GaLV env.