Table 2.

Antiviral activity in sera from transfected suckling mice^a

RNA	Activity at time point (h postinoculation):
	4	8	24	48
S	2	128	162	<2
IRES	64	128	8	<2
3′NCR	<2	32	<2	ND
Poly(I:C)	8	8	<2	<2

^aGroups of four to five mice were inoculated with 100 μg of FMDV transcripts or poly(I:C). Sera were collected and pooled at the indicated times postinoculation for each RNA. Antiviral activity is expressed as the reciprocal of the highest dilution of sera able to suppress VSV-induced cytopathic effect on L-929 cells in 50% of the wells assayed. No antiviral activity was detected in the pools of sera collected at 0 h postinoculation (<2). ND, not done.