NORTHEY 



protein complexes. An increase in heparin would presumably cause 

 a corresponding decrease in the level of circulating lipoprotein. An 

 increase in heparin could presumably also play a role in the in- 

 creased clotting time in cold exposed rabbits reported by Campbell 

 and Sutherland (19 51). It must be pointed out, however, that at the 

 present time, we have no evidence for an increase in heparin in the 

 circulating blood during periods of "cold stress". 



While the consistent "tendency" of the sera of "cold exposed" 

 rabbits to form sharper and clearer zones on starch gel provides 

 a poor indication of any "differences" that might exist, this might 

 be due to a greater degree of homogeneity of each of the different 

 protein components measured by electrophoresis, which would re- 

 sult in a more nearly equal rate of migration. This homogeneity 

 would then be reflected as less "trailing" in the stained starch 

 gel pattern. 



The value of immune- electrophoretic analyses of sera from cold 

 exposed and normal rabbits to the present investigation must await 

 further application of this technique. The limitations when this tech- 

 nique is applied must be recognized. Further experimentation may 

 also be necessary to determine optimal buffer pH values, ionic 

 strength, and so forth, all of which are critical in this procedure. 

 In spite of the apparent limitations of this procedure, however, it 

 offers one of the most sensitive measures of qualitative antibody 

 response that is presently available. 



Future studies which are planned will include analysis of sera 

 from rabbits exposed to more severe environmental conditions 

 (-15 C), and determinations of possible alterations in lipoproteins, 

 haptoglobins, and other serum sub- fractions. Quantitative measure- 

 ments of the 7 S and 19 S macroglobulins will be made by density 

 gradient zone ultracentrifugation and chromatography on cellulose 

 ion- exchange columns. It is anticipated that these and future in- 

 vestigations will provide information useful in determining the role 

 of antibody in host- parasite interactions under conditions of 

 hypothermia. 



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