ANTIBODIES AGAINST RESPIRATORY ENZYMES 379 



and pigeon. A solution of hematin, the prosthetic group common to all 

 the hemoglobins tested, caused no inhibition of the reaction between 

 horse hemoglobin and the homologous immune serum, Hematin also 

 failed to react with immune sera. These facts show that the heme 

 group in hemoglobin does not function as a hapten. For this reason, 

 the hemoglobin solutions of the various species of animals which con- 

 tain the same heme group failed to cross-react with the anti-horse 

 oxyhemoglobin serum. 



Hektoen, et al. (1928) prepared solutions of dog muscle myoglobin 

 ("muscle hemoglobin") free from blood hemoglobin. Serologically, 

 myoglobin was sharply differentiated from the hemoglobin of dog 

 blood. 



The above cited studies show clearly that immune sera against 

 hemoglobins, catalases or myoglobin do not contain anti-heme anti- 

 body. It is therefore obvious that heme, being a common prosthetic 

 group of all the hemoglobins and hemin type of cellular and humoral 

 enzymes, is incapable of stimulating the formation of antibody. 



A carbohydrate isolated from ^-hemolytic streptococcus was found 

 to be serologically inactive (Kendall, et al., 1937). This carbohydrate 

 was found to be a common constituent of synovial fluid, vitreous 

 humor, etc. for which reasons antibody against this carbohydrate 

 was not found in anti-streptococcal sera. 



It may be mentioned that sugars, such as glucose, galactose and 

 lactose, etc. combined with p-aminophenol through an ether linkage 

 and coupled wdth proteins through an azo group, stimulate the for- 

 mation of antibodies. These sugars per se are common to the animal 

 system; however, since they constitute a component of an artificial 

 antigenic complex, they function as antigenic haptens. Aminobenzoyl 

 derivatives of certain peptides such as glycyl-glycine, glycyl-leucine, 

 leucyl-glycine, etc., coupled with proteins through an azo linkage 

 have also been shown by Landsteiner and his associates to stimulate 

 the formation of specific antibodies. These may also be explained in 

 the above manner by assuming that they behave in the animal system 

 apparently as foreign substances. 



The principles underlying the above cited facts may no doubt apply 

 to dehydrogenases, flavoproteins, carboxylases, phosphorylases, etc., 



