Table 5.

Competitive transfer rates of PFV (TW05, ref fluorescence) and SFV_mac (EGFPD, green fluorescence) vectors following simultaneous packaging into PFV or SFV_mac particles.

vectors and packaging systems	fluorescence-positive cells	competitive cross-packaging efficiency
PFV vector (red) +	68% red cells	---
PFV gag pol
SFVmac vector (green) +	67% green cells	---
SFVmac gag pol
PFV vector (red) +	63% red cells	---
SFVmac vector (green) +	0,85% green cells	1.3%
PFV gag pol
PFV vector (red) +	6,8% green cells	---
SFVmac gag pol +	1,2% red cells	15%
SFVmac vector (green)

Vectors were packaged together with the indicated packaging proteins in 293T cells. Supernatants from packaging cells were used for transduction of HT1080 cells. Transduction rates were measured by detection of EGFP and mRFP expression by flow cytometry. The competitive cross-packaging efficiency is calculated from the ratio of fluorescence-positive cells of the heterologous system versus the homologous + heterologous system (e.g. 1.3% = 0.85%/(63% + 0.85%)).