Table 2.

Comparison of Flow Cytometry Titers Based on GFP Transgene Expression Using Two Different Sources for HeLa Cells

Processing Step	TU/mL, HeLa Cells Grown in Own Laboratory	TU/mL, Collaborator’s HeLa Cells	Titer Ratio, Collaborator’s Own HeLa Cells
Combined harvest	6.1 × 105	1.86 × 106	3.02
Processing intermediate	6.17 × 105	1.52 × 106	2.46
Clarified product	4.59 × 105	1.37 × 106	2.97
		Average titer ratio	2.87
		SD	0.25