TABLE 1.

Titers of rNDV V(−) mutants in embryonated chicken eggs^a

Virus	Titer in eggs
	6 days old	10 days old
rNDV	3 × 109	2.5 × 109
rNDV V(−)2ch	4 × 106	1 × 105
rNDV V(−)stop	1 × 102	10

^aEach embryonated egg was inoculated with 10 TCID₅₀ and incubated for 3 days. Infectious titers from the allantoic fluids were determined by IFA in Vero cells.