IMMUNE RESPONSE IN COLD EXPOSURE 



Antibody titrations by the "ring" precipitin method are at best 

 only a crude approximation of the antibody concentration in a serum 

 sample. Because dilutions of antigen rather than antibody are used 

 as a measure of "antibody level", the validity of such titrations has 

 been widely criticized (Roffel, 1961). In spite of this fact, this tech- 

 nique has received wide application, and in this investigation, these 

 titrations have provided a simple and convenient method for approxi- 

 mating antibody levels at various dates during the bleeding schedule, 

 and will be supplemented by the vastly more sensitive micro- 

 quantitative precipitin analyses when time permits. 



Baker and Sellers (1960) have observed in "cold exposed" rats 

 the presence of a plasma protein component which they report has 

 a similar electrophoretic mobility to the "transferrin" component 

 of human serum. This component, also known as siderophilin, serves 

 to bind iron in the circulating blood and migrates as a B globulin. 



While we did not find the presence of a similar "abnormal" pro- 

 tein in the sera of "cold exposed" rabbits, this does not preclude 

 the possibility of the existance of such proteins. Through the use 

 of different stains such as those for haptoglobins or another immuno- 

 chemical technique, like the more definitive disc electrophoresis, 

 similar abnormal proteins may be recognized. 



The "loss" of the B lipoprotein fraction from the sera of a 

 number of "cold exposed" animals as measured by starch gel 

 electrophoresis cannot readily be explained, andmaybedue merely 

 to an alteration in the rate of migration. But this observation 

 provides a fertile field for speculation. Masoro (1960) has reported 

 that the cold acclimated rat has an increased capacity to oxidize 

 long- chain fatty acids. A similar increased capacity on the part of 

 the cold exposed rabbit would partially account for a lower level of 

 slow migrating B lipoprotein in this animal. Bertke (unpublished 

 data) and others have reported a decrease in lipid content of the 

 adrenals during stress. Such a decrease could presumably be re- 

 flected in a decreased level of circulating lipoprotein. A final 

 speculation concerning a decreased B lipoprotein content of cold 

 exposed rabbits concerns the role of heparin during periods of 

 stress and/or shock. This compound, because of its strong polar 

 properties, is capable of liberating the combined lipid from lipo- 



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