CAMPBELL 

 DISCUSSION 



SULKIN: In the antigen decay experiment with the Arctic 

 ground squiin^elj I wonder if you have attempted such an ex- 

 periment at a time when the animal does not ordinarily go in- 

 to hibernation? In other words, have you measured antigen at 

 another season of the year, such as the summer time? 



CAMPBELL: Yes, even while they are active both antigen 

 and antibodies disappear very rapidly in the summer time. It 

 is a problem because squirrels do become active a while be- 

 fore they come out of their bui'rows, so actually you have to 

 dig them out. We did have an artificial setup at Point Barrow, 

 finally. It took us about two years to learn how to get them to 

 hibernate. The first two years they all died; the next year some- 

 body got some ambition and hauled down a few tons of sand from 

 the Mead River where these squirrels live. The sand was put 

 in a wire enclosure so the squirrels couldn't get out, and we 

 could go out to the pen and dig them up. They become active 

 for a couple of weeks before they come out of hibernation, 



MONCRIEF: Does the inability to form antibody also imply 

 an increased destruction of antigen? 



CAMPBELL: I can't answer that because they go hand in hand. 

 Now, in the production of antibody, antigen is destroyed. This 

 is a fact. Now, whether antigen has to be destroyed, I don't know. 

 Supposing it was not destroyed. If it is not broken down, it is 

 not antigenic. We think that antigen is broken down into par- 

 ticles about the size of templates, and that antibody formation 

 is just modified biosynthesis of gamma globulin by the RNA, 

 because it is always associated with the soluble RNA; we know 

 the soluble RNA does turn over during protein synthesis, and 

 the more protein being synthesized, and the more active the 

 cell is, the greater the rate cf this turnover. Well, when it 

 breaks down and turns over, then this template, or some of 

 it, may be lost. This is a reflection of the rapid protein syn- 

 thesis, and some of these fragments are always being secreted 



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