METHODS IN MAMMALIAN IMMUNOGENETICS 355 



Table 60 



Absorption analysis leading to the recognition of two 

 specificities 



Antiserum 

 Unabsorbed Absorbed with cells of individual: 



The unabsorbed antiserum evidently contains two distinct antibody fractions discernible with 

 these test cells, recognizing four cell types, A, B, AB, and (-). Absorbing with type A leaves anti-5; 

 with B leaves z.nt\-A. 



be shown that each of these cells removes all of the antibody reactive with each of the 

 others. Very frequently, an antiserum will require three or four or more sets of 

 symbols for its consistent analysis (for example, antw4, anti-Z?, anti-C, anti-Z)). The 

 analysis of such an antiserum provides an interesting exercise. The behavior of each 

 cell in both the absorption columns and the test rows of the table, and relative to the 

 behavior of all other cells in the test, must be consistent with the symbolic designations. 

 In such complex situations, unit reagents are often achieved only after further absorp- 

 tions with pools of two or more cells of different symbolic types. Realistically, we must 

 observe here that frequently deviations from ideal behavior are observed in these 

 complex systems, such that, for example, a given cell may appear to be removing anti- 

 body in absorption with which it does not appear to react in tests. The published 

 work in this field is generally based on selections of reagents that behave in logical and 

 consistent fashion, and authors and teachers in this field often ignore a tangled hinter- 

 land of poor reagents set aside, unused and unexplained, that violate the principles of 

 straightforward symbolic absorption analyses. 



Genetically, reactions that require two sets of symbols (such as A versus non-yl; 

 B versus non-5) are often found to depend on two independent pairs of alleles. Fre- 

 quently, however, multiple allelic series are discerned ; some of the longest multiple 

 allelic series in all genetics are noted in this field. When sets of specificities are found 

 to depend on a series of multiple alleles, there are very frequently cross reactions among 

 the products of related alleles. This situation, dependent mainly on the lack of 

 complete specificity of serologic reactions, leads to uncertainties regarding the sig- 

 nificance of the symbolic designation of antigens, in terms of their antibody reactions, 



