MIYA, MARCUS AND PHELPS 



temperature. We were trying to compare mice of a different genetic 

 makeup, but were defeated in the attempt. 



MARCUS: Didn't we have a similar experience with some 

 dark mice? 



MIYA: We have not used black mice in any of our experiments. 



BERRY: This shows the same difference in mice in a very 

 dramatic way. The other question I have is in regard to this 

 endotoxin. You injected it 48 hours before the infectious challenge 

 and within this period of time, as I recall, in some cases there 

 should be an increase in non-specific resistance capable of pro- 

 tecting them against bacterial challenge, 



MARCUS: We chose that time because it has been subscribed 

 to, and we had the same results. There is a very critical time 

 for inducing protection. You remember that this time is quite 

 critical, because if you challenge about four hours after endo- 

 toxin administration there is a decrease in resistance. Also, 

 if you wait much beyond three days, it is all gone. 



BERRY: Has an increase in non-specific resistance ever been 

 shown to protect against a viral challenge under any condition? 



MARCUS: Not that I know of.^ 



BERRY: I don't remember either. 



TRAPANI: Does anyone ever use AKR mice for long term ex- 

 periments on cold exposure? In regard to some of the remarks 

 you made about the neoplasms and virus studies, it would be in- 

 terestir^ to study the AKR mouse. This strain of mouse shows 

 spontaneous development of leukemia and lymphoma at about nine 

 months to one year of age, and this condition has been considered 

 to have a viral etiology. It would be interesting to use the AKR 



6 See article by Nemes and Hilleman, Proc. Soc. Exp. BioL. Med. 110: 500. 1962, in 

 which endotoxin is shown to increase resistance in mice against some but not all virus 

 infections. 



212 



