NORTHEY 



nificantly large number of animals succumbed from non-specific 

 causes during the course of the various studies in the cold exposed 

 group compared to deaths in those maintained at room temperature. 



The quantitative evaluation of sera from each of the groups has 

 provided some interesting information regarding the immune re- 

 sponse under conditions of cold exposure. Antigens of varying com- 

 plexity were used, and the response of the animals measured. The 

 comparatively less complex antigens, egg albumin (Ea) and bovine 

 serum albumin (BSA), provide a sharp contrast to the very complex 

 human serum and bovine serum in terms of multiplicity of antigens 

 to which the antibody forming cells must respond. The failure to 

 find a sig-nificant qualitative difference in the experimental and 

 "control" groups indicates that cold exposure does not appreciably 

 affect the total response of an animal to multiple antigen systems. 

 The level of the response, as well as the time required for antibody 

 response, did not differ significantly in any of the gel diffusion 

 studies. In spite of the failure to attain statistical significance in 

 these studies, it must be remembered that these data do not provide 

 a final critical measure of antibody response during hypothermia, 

 Campbell et al. (19 51) and Sutherland et al. (19 58) have measured 

 the rates of antibody decay during both active immunization and 

 passively administered antibody. These authors report an increased 

 rate in decay of both actively formed and passively administered 

 antibody in cold exposed rabbits. Extrapolation of these findings to 

 the data presented here and increased rate of "decay" may provide 

 a more sensitive measure of the actual difference, and result in 

 the weighing in favor of an increase in antibody production in the 

 "cold exposed" animals. Such an extrapolation is, of course, im- 

 possible on the basis of our present knowledge of the mechanisms 

 of protein metabolism and protein turnover in the immunized 

 animal. 



It should be pointed out that I am well aware of the inherent 

 dangers in lending too much credence to the results of an evaluation 

 by gel diffusion. Numerous investigators have demonstrated that 

 this procedure is dependent upon a variety of physico-chemical 

 factors, and that this technique, regardless of how critically 

 applied, is subject to error (Glenn, 1959; Jennings et al., 1962). 



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