VIRULENCE AS A FACTOR IN HOST RESPONSE TO BACTERIAL 

 INFECTION AT LOW ENVIRONMENTAL TEMPERATURE^'^ 



Joseph J, Previte^ and L, Joe Berry 



Department of Biology, Villanova University 



Villanova, Pennsylvania 

 Department of Biology, Bryn Mawr College 

 Bryn Mawr, Pennsylvania 



ABSTRACT 



The purpose of this report has been to investigate the effect of acute exposure to 

 cold on the response of mice to Salmonella typhi murium and Staphylococcus aureus , 

 and to injections of lipopolysaccharides derived from Gram negative organisms. Mice 

 maintained in individual compartments without bedding following infection with an a- 

 virulent strain of either Salmonella typhimurium or Staphylococcus aureus are more 

 susceptible when exposed continuously to 5° C than they are when exposed to 15° C or 

 to 25° C. These differences are not observed when virulent strains are used, while 

 acclimatization to cold for two weeks fails to alter the response to the avirulent organ- 

 isms. Mice kept at 5° C post-injection are sensitized 250-fold to pasteurized Salmonella 

 typhimurium , and about 10-fold to lipopolysaccharide derived from Serratia marcescens 

 compared to control animals housed at 25° C. Mice given an LD^g dose of lipopoly- 

 saccharide and placed at 5° C for 12 hours before transfer to 25° C are as susceptible 

 to the endotoxin as mice kept continuously in the cold. Conversely, mice given the same 

 dose and retained at 25° C for 6 or 12 hours before placing them at 5° C are almost 

 as resistant as mice kept continuously at 25° C. The period of sensitization to lipo- 

 polysaccharide following cold exposure was paralleled by the time at which a drop in 

 body temperature occurred following the low temperature stress and/or endotoxin 

 poisoning. Protection was afforded the cold exposed mice against endotoxin poisoning 

 by exogenously administered cortisone acetate while 8 units of ACTH enhanced the 

 lethal effects of the toxin. The adrenal response of the host to temperature stress seems 

 to be of paramount significance in determining sensitization to lipopolysaccharide. 



1 Some of the data presented inthis paper has been published in the Journal of Infectious 

 Diseases HO: 201-209, 1962. 



2 This work was supported in part by contract AF 41 (657)- 340 between Bryn Mawr 

 College and the Arctic Aeromedical Laboratory. 



3 Present Address: Zoology Department, Smith College, Northampton, Massachusetts. 



215 



