14 INTRODUCTION TO IMMUNOCHEMICAL SPECIFICITY 



Anti-metanilic acid(M) Antigens made with chicken serum and: 



antiserum absorbed with 



azo-stromata made with: M GAB 



+ + ± 



+ + + +± 



+ + + +± 



(Unabsorbed) + + + ± ++ + +± 



Fig. 2-2. Precipitin reactions of absorbed anti-metanilic acid antiserum with 

 various conjugated antigens. 



suggested that we should think of the antibody molecules of an im- 

 mune serum as "a large family, with varying degrees of deviation from 

 a mean." Pauling, Pressman, and Grossberg (1944) made a similar 

 and more precise suggestion. In their opinion, the free binding ener- 

 gies of the different antibody molecules (for the determinant that 

 induced their formation) are distributed according to the Gauss 

 error function.* 



In the description of the reactions of antibodies with simple sub- 

 stances (haptens) it was stated that to detect anti-metanilic acid 

 (anti-M) antibodies, for example, we make use of a protein, different 

 from the one used as the carrier of the hapten during immunization, 

 coupled with diazotized metanilic acid. It may have occurred to the 

 reader to ask what would happen if we mixed the anti-M serum di- 

 rectly with metanilic acid? 



* This is the well-known "normal distribution" formula of statistics, 

 fix) = [l/aV(27r)]exp i-xyia') 

 where a, called the standard deviation, is a measure of the "dispersion" or degree 

 of heterogeneity of the population whose composition is summarized by the 

 curve. Two graphic examples of this distribution are shown in Fig. 2-3. 



