EFFECT OF LOW AMBIENT TEMPERATURES ON SPECIFIC 

 AND NONSPECIFIC RESISTANCE 



Fred Miya, Stanley Marcus and LeGrande J.^Plj^lp© 



University of Utah 

 College of Medicine 

 Salt Lake City, Utah 



ABSTRACT 



Adult albino mice ( Mas musculus ) have been employed in a series of experiments 

 to determine the effect of acute and chronic low temperature exposure on resistance 

 to bacterial disease. Disease organisms used were Klebsiella pneumoniae and Staphyl- 

 ococcus aureus. Animals challenged with these organisms had been previously immu- 

 nized with the specific agent or had been pretreated with zymosan or Escherichia 

 coli endotoxin. Groups of mice kept at 21° C were compared to similarly treated 

 groups kept at 2° C for 30-45 days. Also, mice challenged at 21° C were then placed 

 at 2° C. The mice challenged at 2° C were kept at this same temperature, caged 

 either singly or in groups. The results show that under these conditions specific 

 immunization affords significant protection as compared to nonspecific immunization 

 of the animals. The degree of resistance induced by nonspecific immunization is 

 significant by comparison with the control animals. The extent of protection is de- 

 creased if the animals are acutely cold stressed as compared to chronic cold stress. 

 Also, specific immunization does not protect animals as well if they are caged in- 

 dividually at the cold temperature as compared to being caged in groups; thus, psy- 

 chological factors of isolation should not be disregarded. It is concluded that specific 

 immunization affords increased resistance compared to nonspecific immunization; 

 however, the degree is dependent on factors such as grouping and chronicity of ex- 

 posure. 



Reported results vary concerning the effect of exposure of experimental animals 

 to cold on virus-induced diseases. In some cases resistance has been found to de- 

 crease, in other cases resistance has been found to remain unchanged or to increase. 

 Different routes of challenge, viral agents, animal species employed, and variations 

 in caging, such as individual or grouped, are among the variables which may account 

 for apparently diverse results reported. Experiments were conducted with one strain 

 of adult albino Mus muscullus to determine the effect of acute and chronic exposure of 

 these animals on induced viral disease. The mice were kept at either 2° C or room 

 temperature (ca. 21° C). The viral agent chosen was a strain of Coxsackie B-5 which 

 will infect the mice following intraperitoneal injection. Results indicate that: (1) Acute 

 exposure followed by challenge results in lowered resistance. (2) Specific immunization 

 affords significantly increased protection which is not reduced by acute exposure. 

 (3) Nonspecific immunization enhances resistance above that shown by untreated animals, 

 but the extent of resistance is less than that achieved by specific immunization. If the 

 animals are first acclimatized to cold and then challenged, results are changed in the 

 following manner: (1) Acclimatized mice are capable of withstanding challenge doses that 



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