Table 1.

Comparison between physical and infectious titers of MV-derived LVs versus VSV-G-LVs obtained with different cell lines^a

Vector (100× concentrated)	Mean titer ± SD
	293T (TU/ml)	CHO-SLAM (TU/ml)	Raji (TU/ml)	p24 (ng/ml)
H/F-LVs	4.7E6 ± 4,5E6	4.1E 7 ± 2.9E7	6.7E7 ± 2.1E7	155 ± 67
VSV-G-LVs	4.5E8 ± 1.8E8	8.4E7 ± 1.5E7	7.4E8 ± 1.1E7	182 ± 62

^aSupernatants of 293T producer cells were concentrated 100-fold by low-speed centrifugation. Titers for the 293T, CHO-SLAM, and Raji cells were assessed by adding serial dilutions of each vector preparation to the appropriate target cell. For each vector, the percentage of GFP⁺ cells was analyzed at day 3 posttransduction. Vectors were titered on 293T, CHO-SLAM, and Raji cells. Titers are expressed as mean transduction units (TU) per ml (n = 6). For the p24 cells, the titers are expressed as the p24 level (in ng/ml) determined by ELISA that represents a measure for the total physical particles present in the vector preparation.