ANTI-ENZYME IMMUNITY 217 



tate. Normal sera did not form a precipitate with emulsin. If immune 

 sera were added to either lactose, arbutin or amygdalin together with 

 emulsin the hydrolysis was diminished or abolished. Despite these 

 facts, Bayliss did not believe that the inhibition of the activity of the 

 enzymes in emulsin was due to an immune reaction. In support of his 

 belief, Bayliss also made the statement that: "Incidentally it is shown 

 that emulsin is not of protein nature." The experimental data of Bay- 

 liss have been subjected to a critical analysis by us, particularly the 

 results concerning the effect of H+ concentration on the reaction 

 systems he used. We have found that Bayliss' results show a 79 per 

 cent inhibition of the enzyme by immune rabbit serum which is due 

 to emulsin-antiemulsin reaction. 



Moreover, the objection of Bayliss that the variation of H+ con- 

 centration is responsible for the anti-enzyme inhibitory effect has been 

 carefully investigated by various investigators (Liiers and Albrecht, 

 1926; Schubert, 1933; Smolens and Sevag, 1942, etc.); in all these and 

 other studies, under carefully controlled H+ concentration the inhibi- 

 tory effects of anti-enzyme sera are found directly related to antigen- 

 antibody combination. 



Dochez and Avery (1916) reported that antipneumococcal serum 

 added to a culture of pneumococcus in inulin completely suspended 

 the fermentation of the inulin. Heterologous immune serum delayed 

 the reaction but did not entirely inhibit it. The fermentation of sugars 

 and saccharose was not inhibited to the same degree as that of inulin. 

 The rate of production of acid in cultures containing such easily fer- 

 mentable sugars was markedly delayed by immune serum in the early 

 hours of growth. The demonstration of the presence of anticarbohy- 

 drases in antipneumococcal sera capable of inhibiting the hydrolysis 

 of inulin appears to corroborate the finding of Saiki (1907), who re- 

 ported having produced antibody in animals against inulase. Dochez 

 and Avery took blood serum from patients at intervals during an attack 

 of lobar pneumonia and found that the serum exercised anti-enzymatic 

 action similar to that of immune serum developed during the period 

 of recovery from the disease. In view of the high degree of inhibitory 

 action of the immune sera on the bacterial enzymes, they suggested 

 that these properties play an important part in resistance and immunity 

 to infection with pneumococcus. 



