TABLE 2.

Formation of HSV infectious centers and plaques on susceptible BHK(TK⁻) cells, resistant U_S11cl19.3/pcDNA cells, and HVEM-expressing U_S11cl19.3/BEC cells

Test cells	Input PFUa	HSV-1(F)		HSV-2(G)
		Infectious centersb	Test cell plaquesc	Infectious centers	Test cell plaques
BHK(TK−)	5 × 104	TNTCd	TNTC	TNTC	TNTC
	5 × 103	128	232	84	80
	5 × 102	14	22	16	28
US11cl19.3/pcDNA	5 × 107	TNTC	0	TNTC	1
	5 × 106	98	0	56	0
	5 × 105	6	0	2	0
US11cl19.3/BEC	5 × 107	TNTC	32	TNTC	76
	5 × 106	58	2	36	10
	5 × 105	6	0	0	0
	5 × 104	0	0	0	0

^aDetermined by titration of virus stock on Vero cells. 

^bNumber of plaques obtained following seeding of infected test cells onto a Vero cell monolayer in the presence of neutralizing antibody. 

^cNumber of plaques observed on the infected test cell monolayer. Plaques are defined as two or more adjacent infected cells. Macroscopic plaques were rarely formed on U_S11cl19.3 cells. 

^dTNTC, too numerous to count.