420 BACTERIOLOGICAL CHEMISTRY 



may be eliminated by treatment not substantially affecting 

 the globulin as a whole, depending on the point of attack. 



Production of Antibodies. — We still do not Imow how 

 antibodies are produced in response to the injection of 

 antigens. It has been suggested that antibodies differ 

 from normal serum globulins in that they incorporate 

 the antigen in their structure and owe their specificity to 

 that fact. This theory seems hardly tenable for several 

 reasons ; an extremely small quantity of an antigen can 

 induce the formation of almost limitless amounts of 

 antibody. Animals repeatedly bled after injection of a 

 single small dose of antigen go on manufacturing antibody 

 in quantity which would exhaust the supply of antigen 

 many times over, however little of it were incorporated. 

 More positive evidence is afforded by experiments made 

 with artificial antigens containing an easily detectable 

 hapten group such as the atoyxl group or certain dye 

 groups ; in no case has a trace of that group been detected 

 in the antibodies resulting from the injection of such 

 antigens. A suggestion, made by Breinl and Haurowitz 

 and by Mudd, which seems more possible is that the anti- 

 bodies are synthesised from amino-acids and peptides at 

 the surface of the antigen which, due to its stereochemical 

 spacing or distribution of surface charges, acts as a sort 

 of template and impresses its specificity on the newly 

 formed protein in that way. The antibody is supposed 

 to differ from normal globulin in the order in which the 

 amino-acids are incorporated into the protein chain, the 

 new order being imposed by the presence of the antigen. 

 The complex of antigen and antibody so formed is as- 

 sumed to dissociate, the antibody being liberated into the 

 blood-stream and the antigen being left free to influence 

 the synthesis of further amounts of the antibody. 



Work by Cannon and his collaborators has shown that 

 the formation of antibodies is associated with the syn- 

 thesis of globulins in the l)ody, and depends on an 

 adequate supply of amino-acids in the form of protein 



