TABLE 2.

Viral titers generated by PG13 cells transfected with vector plasmids^a

Expt	Viral titers (104 CFU/ml)
	MP1	SR6-2wtLTR	SR2-2GFP	SR5-FP-GF	MS2-FP-GF-no3R
A	74	12	ND	2.4	1.1
B	44	19	6.1	1.6	4.8
C	16	8.3	4.1	13	11
D	43	17	5.9	4.0	3.2
E	130	130	14	24	21

^aIn general, within each set of experiments, RT activities were within 1.5-fold among cell pools transfected with different vectors. ND, not determined.