Table 3.

RacL11ΔIR4 Fails To Replicate in the Lungs of CBA Mice.

	PFU Titer Determined in Equine NBL6 Cells
Virus	inoculum†	2 days pi‡	4 days pi‡	6 days pi‡
RacL11ΔIR4	5 × 105	<50	<50	<50
RacL11BD	5 × 105	4.6 × 106	2.6 × 105*	4.7 × 103**

^†= pfu;

^‡= pfu/lung;

n = 5 mice per group;

^*one mouse succumbed to infection;

^**two mice succumbed to infection. RacL11BD is parent RacL11 virus derived from BAC.