28 



INTRODUCTION TO IMMUNOCHEMICAL SPECIFICITY 



5 to 9 kcal. per mole. See Chapters 9 and 10.) Hooker and Boyd 

 (1941) suggested that the combining group of the antigen might fit 

 into a cavity in the antibody. Pauling made a similar suggestion. 

 Figure 2-11 shows Pauling's conception of antibody cavities corre- 

 sponding to 0-, m-, and /'-aminoarsonic acid. 



To what extent such a cavity in the antibody is merely schematic 

 ;and to what extent it is real is not yet decided. The concept has 

 certainly proved useful in thinking about antibody-antigen reactions. 



Fig. 2-12. Schematic drawings of three possible types of cavities (deter- 

 minants) in antibody molecule: 1, invagination; 2, shallow trough; 3, slit 

 trench. 



