TABLE 2.

Comparison of pathogenicities of OSU virulent and attenuated NSP4 and mutant P138S NSP4 given intraperitoneally to 6- to 7-day-old CD1 mice

Expta	Inoculum	Dose	No. of mice with diarrhea/no. inoculated	Avg scored	DD50 (μg)
1	OSU-v NSP4	5 μg	13/23b	2.8	3.2
	OSU-a NSP4	5 μg	4/25	2.5	>10e
	PBS	50 μl	1/25c	2.0
2	OSU-v NSP4	5 μg	7/12b	2.8
	P138S	5 μg	0/12
	P138S	10 μg	0/12
	PBS	50 μl	0/12

^aAll experiments were performed with coded samples. 

^bP < 0.01, chi-square test. 

^cOne mouse exhibited minimal diarrhea at one time point. 

^dAverage score of disease severity for animals with diarrhea (4). 

^eUnable to be determined because of limitations in NSP4 solubility.