ANTI-ENZYME IMMUNITY 211 



out complement use just as much oxygen as non-agglutinated or 

 control systems. The results with E. typhosa, 0-901 strain, were similar 

 to those obtained with pneumococci. These findings show that the 

 layer of antibody specifically deposited on the surface or cell-wall of 

 microorganisms, with or without agglutination, do not constitute a 

 mechanical or physical barrier to the penetration of glucose or glycerin 

 to the active sites of enzymes if the latter are not inactivated by an 

 antigen-antibody combination. In a study with Salmonella Harris 

 (1948) obtained results similar to that discussed above. The question 

 of whether or not protein or starch molecules can squeeze themselves 

 to the sites of the specific enzymes of agglutinated bacteria through the 

 layer of deposited antibody molecules remains to be asked. 



In this connection an observation by Feiner, et al. (1946) is of con- 

 siderable interest. They studied the ability of lysozyme to attack a sub- 

 strate (antigen) precipitated by homologous antibody. They observed 

 an unmistakable difference in the appearance between the untreated 

 and enzyme-treated immune precipitates. The control, untreated pre- 

 cipitates remained as opaque white pellets, whereas in the treated series 

 they appeared as translucent vacuolated material closely adherent to 

 the bottom of the tube and markedly diminished in size. Antibody 

 was released as a result of lysozyme action. They concluded that lyso- 

 zyme is capable of attacking the organism, or its mucopolysaccharide, 

 as substrate when either is combined with antibody. Lysozyme has a 

 molecular weight of 15,000 to 18,000 and is a protein. Its substrate, 

 mucopolysaccharide, is antigenic and combines with antibacterial 

 serum. The ability of lysozyme to depolymerize this antigen (substrate) 

 when in combination with antibody molecules shows that the latter 

 occupying positions on the antigen molecule leave free spaces through 

 which lysozyme can readily make contact with the enzyme-susceptible 

 groupings, or that mutual affinities between an enzyme and substrate 

 cause displacement of the antibody molecules from their combining 

 sites on the antigen. Whichever explanation is considered more 

 plausible, the fact remains that either the antibody molecules are 

 incapable of forming a wall around or on the surface of an antigen 

 which is impermeable to a protein of 15,000 to 18,000 molecular 

 weight, or that the enzyme competes with the antibody for the same 

 site on the substrate (antigen) molecule and is capable of displacing 

 it. If we consider these relationships even in a most conservative man- 



