TABLE 1.

Transduction efficiency of the tat-deficient HIV vector^a

Vector	Promoter	Tat expression	Mean titerb (LFU/ml of virus stock) ± SD
—c	NAd	NA	<1
pH5Z	HIV-1 U3	+	(9.7 ± 2.4) × 105
pH3Z	HCMV IEe	+	(2.9 ± 0.5) × 105
pH4Z	HCMV IE	−	(3.0 ± 0.2) × 105

^aViral stocks were generated by cotransfection of pGP-RRE3 (7 μg) and pRV67 (5 μg). Results are from a representative experiment of a total of four performed. 

^bTiter was measured on 293T cells by counting the number of blue colonies following 5-bromo-4-chloro-3-indolyl-β-d-galactopyranoside (X-Gal) staining 48 h after transduction. 

^cInstead of a vector genome construct, 8 μg of pCI-neo was transfected. 

^dNA, not applicable. 

^eHCMV immediate-early enhancer-promoter.