MET CALF 



PREVITE: Your findings are parallel in some ways to those 

 that I have reported on endotoxin. If cold exposure was delayed 

 too long, the animal had manipulated this poison somehow so 

 that he was no longer sensitized to it by cold stress. 



WALKER: Then your test material is gone. 



PREVITE: Correct. 



SULKIN: Dr. Campbell called attention to the fact that the 

 infant mouse does not produce antibody, Coxsackie viruses are 

 unique among viruses in that they elicit an antibody response 

 very, very, rapidly. In man, for example, antibodies are demon- 

 strative very early after first signs of infection. Yet a week- 

 old mouse will produce antibody, whereas the one-day- old mouse 

 will not. Overland showed that the maturation of the antibody 

 forming mechanism in the animal accounts for this rapid acqui- 

 sition of resistance to infection with Coxsackie viruses. 



MITCHELL: Will someone please define for me this infant 

 mouse? Don't say baby; I know that, 



WALKER: In Coxsackie B-1 virus infection, for instance, the 

 mouse is most sensitive to the virus up to about forty- eight 

 hours in age. Large inocula of this virus will cause lethal in- 

 fections in mice up to about eight days of age, but then there 

 is a very abrupt cut-off with no deaths occurring in mice in- 

 oculated at an older age. But the mice are most susceptible to 

 small inocula in their first forty- eight hours after birth. 



MITCHELL: I was interested in those extra days of exposure; 

 after this delay, the animal would be ten, eleven, or twelve days 

 old. 



WALKER: No, you misunderstood, because this exposure to 

 cold is in adult mice. The infant mouse enters in here only be- 

 cause the adult mouse in the cold behaves rather like the infant 

 mouse at normal room temperature. 



PREVITE: Dr. Walker, in some of your data you mentioned 



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