1 30 IMMUNO-CATALYSIS 



Granting that d- and 1-active antigens might catalyze the synthesis 

 of homologous antibodies, comparable to the catalytic synthesis of d- 

 and 1-active substances respectively by 1- and d-active organic cata- 

 lysts, it would then appear reasonable to expect that hypothetically 

 d-antigen catalyzes the synthesis of 1-antibody and 1-antigen that of 

 d-antibody. The serological reaction between the optically active anti- 

 gens and the homologous antibodies would then be comparable with 

 the formation of a racemate such as d-cinchonine-1-tartrate. This 

 racemate is a relatively more insoluble molecular combination than 

 either of the components, which fact might be compared with the 

 formation of an insoluble precipitate by the reaction between the 

 antigen and antibody. 



The protein molecule is made of optically active amino acids which 

 have the 1-configuration. Lettre (1937) postulated that in the anti- 

 body molecule the serologically determinant group as the prosthetic 

 group is the mirror image of the naturally occurring 1-active groups 

 of the normal globulin molecule. A simple protein acting as antigen 

 would produce accordingly an antibody containing as many d-active 

 prosthetic groups as there are antigenic 1-active groups in the simple 

 protein. Though this concept might appear to account for the 

 formation of hypothetical d-active antibodies against 1-active antigens, 

 difficulty arises when we attempt to explain the nature of the active 

 groups in the antibody molecule produced against d-antigens. Since 

 the antibody against the latter would hypothetically be expected to 

 have the 1-configuration, it is difficult to conceive that there can be two 

 kinds of 1-active globulins to account on one hand for the serological 

 reactivity of the antibody against the d-antigen, and a second one 

 corresponding to normal globulin made of 1-active amino acids on the 

 other. 



Antibody Carbohydrate as a Possible Seat of Specificity. Perhaps 

 it is pertinent to the question discussed above to consider the possible 

 role of the carbohydrate contained in the antibody globulin on the 

 specificity of serological reactions. As far as we know, this question 

 has never been raised or studied before. It has been shown by Hewitt 

 (1938) that normal serum globulins contain chemically bound 

 carbohydrate groups. Working with normal serum fractions which 

 were distinguishable by biological, chemical, and physical methods he 

 found that seroglycoid, globoglycoid and pseudoglobulin, respectively, 



