DISCUSSION 71 



the other components should not have been affected by the presence of 

 the inhibitor. 



Davies: There is only one thing in common there. For example, 

 when I had D^EK serum, I got very good inhibition with the homolo- 

 gous (in the true sense) substance. Now if I have a material extracted 

 from mice which carried some other H-2 specificities but had E, but not 

 D^ or K, then I get a lesser degree of reaction. 



Amos: What were the test cells ? 



Davies: The test cells v/ere D^, E and K and were from the mouse 

 which provided cells for immunization. So we were picking up all 

 three things there. In my Table V they were monospecific sera, or at 

 least very nearly so, but in my Table IV we were testing for several 

 characters, and I believe they are genuine cross-reactions. Where you 

 say anti-K should still have agglutinated, it would probably not do so 

 because we have diluted the antibody to the extent that the homologous 

 cells are only just agglutinated, in order to achieve maximum sensitivity. 



