TABLE 3.

Titers of IE1- and ICP4-positive cells, complemented FFU titers, and reactivated PFU titers of vEG-dl110, in comparison with PFU titers in HFFF-2 and U2OS cells, and relevant comparative titers of HSV-1 strain 17^a

Parameter	U2OS cell titers		HFFF-2 cell titers
	Strain 17	vEG-dl110	Strain 17	vEG-dl110
PFU	1.5 × 108	2.2 × 108	6.7 × 107	1.5 × 105
6-h FFU
ICP4	4.8 × 108	5.8 × 108	5.5 × 107	4.0 × 107
IE1	5.2 × 108	6.0 × 108	1.0 × 108	1.8 × 108
IE1 + ICP4	6.6 × 108	7.0 × 108	1.0 × 108	1.9 × 108
24-h FFU
ICP4	NDb	ND	1.9 × 108	3.2 × 107
IE1	ND	ND	1.9 × 108	5.2 × 107
IE1 + ICP4	ND	ND	1.9 × 108	6.0 × 107
6-h FFU + in1411
ICP4	ND	ND	ND	3.4 × 108
IE1	ND	ND	ND	3.3 × 108
Reactivated PFU	ND	ND	ND	2.0 × 108

^aIE3 FFU titers were determined by ICP4 staining for all three viruses. IE1 FFU were determined by staining for EGFP in vEG-dl110 infections. IE1-plus-ICP4 titers reflect cell numbers detected by staining simultaneously for ICP4 and EGFP. Further details are given in the text. The experiment was repeated, and similar results were obtained.

^bND, not determined.