TABLE 3.

Effect of MPA on the anti-VZV (wild-type and TK⁻ strains) activities of ACV and GCV

Virus strain	Antiviral agent	EC50 (μg/ml)a
		GCV alone	ACV alone	With MPA at 10 μg/ml	With MPA at 2.5 μg/ml	With MPA at 1.0 μg/ml
OKA (TK+)	GCV	0.86 ± 0.89		0.09 ± 0.09	0.11 ± 0.12	0.11 ± 0.12
	ACV		0.45 ± 0.07	0.06 ± 0.04	0.05 ± 0.03	0.08 ± 0.02
YS-R (TK−)	GCV	27 ± 31		1.5 ± 1.1	1.6 ± 1.0	1.4 ± 1.4
	ACV		27 ± 20	0.8 ± 0.6	1.5 ± 0.7	0.55 ± 0.07

^aData are mean values for two separate experiments. The EC₅₀ of MPA alone is >10 μg/ml.