TABLE 1.

HIV Gag production

Plasmid	Gag concn (pg/ml)a
	COSb	D17c
pSVgagpol-rre	<MDd	<MD
pSVgagpol-rre + pRev1	6,000	3,300
pSVgagpol-rre-MPMV	5,500	2,100
pSVgagpol-rre-LTR	<MD	<MD
pSVgagpol-rre-LTR + pRev1	6,100	3,200
pSVgagpol-rre-3′UTR	<MD	<MD
pSVgagpol-rre-3′UTR + pRev1	6,500	4,000
pKB504gagpol	600	600
pKB504gagpol-MPMV	2,800	900
None (mock transfection)	<MD	<MD

^aRepresentative data from at least three independent transfections. Three days posttransfection, cell-free supernatant medium from 3 × 10⁵ cells was harvested, and Gag levels were quantified by Gag ELISA and normalized to transfection efficiency. 

^bCOS cells were transfected with a mixture of Lipofectamine (Gibco-BRL) and test DNA (1.5 μg and 0.3 μg of pRev1) plus 0.2 μg of pEGFPN1 reporter plasmid. After 5 h, the cells were washed and cultured in 2 ml of DMEM with 10% fetal calf serum. Transfection efficiency was determined as percentage of green fluorescent cells in 1,000 cells. 

^cD17 cells were transfected with a mixture of Polybrene (30 μg/ml), test DNA, and pEGFPN1 or pCMVluc and then cultured in DMEM supplemented with 5% fetal calf serum. 

^d<MD, less than the minimum detectable.