Table 1.

Infection of newborn DDD mice with Mo-AmphoV alone or together with F-MuLV, Mo-MuLV, or F-MCFV

Virus and coninfectant*	No. of mice	Spongiform degeneration†		Leukemia‡
		Incidence, %	Latency (mean)	Incidence, %	Latency (mean)
Mo-AmphoV
Alone	16	22	250	78	188
F-MuLV	10	90	53	10	44
Mo-MuLV	16	100	64	0	—
F-MCFV	10	100	41	0	—
F-MuLV
Alone	19	0	—	100	110
Mo-MuLV	16	0	—	100	95
F-MCFV	10	0	—	100	96

^*DDD mice were infected i.p. between 24 and 48 hr after birth with 50 μl of virus supernatant with titers between 3 × 10⁵ and 1 × 10⁶ units/ml. 

^†Onset of spongiform encephalomyelopathy was determined by penetrance of hindleg paralysis, and, in most cases, the disease was confirmed by histopathology. 

^‡Leukemias were morphologically classified as lymphatic leukemias (cells were Thy1⁺).