ANTI-ENZYME IMMUNITY 229 



Serological S'pecificity of Dextran and Levulan. Hehre (1941) re- 

 ported that cell-free enzyme preparations incubated with lactose, malt- 

 ose, arabinose, xylose, galactose, fructose, dextrose and a mixture of 

 dextrose and fructose failed to produce serologically reactive poly- 

 saccharide. Sucrose, and raflfinose (sucrose grouping linked with 

 a-galactose) to a slight degree, were the specific substrates for the 

 synthesis of serologically active dextran. This polysaccharide was found 

 to react with the antiserum of types 2 and 20 pneumococci as well as 

 with the antiserum of the homologous bacterium, L. mesenteroides. 



Optimal activity of the enzyme was at pH 5.0 to 6.0 and 23°C. 

 (tiehre and Sugg, 1942; Hehre, 1946). The enzyme was completely 

 inactivated by heating for five minutes at 55°C. The polysaccharide, 

 unlike starch or glycogen, gave no color with iodine. It did not contain 

 galactose, fructose, pentoses or uronic acids. On hydrolysis it contained 

 90 to 94 per cent reducing sugar, glucose-phenylosazone was isolated, 

 and on oxidation with nitric acid, potassium acid saccharate was ob- 

 tained. 



Purified polysaccharide prepared with cell-free enzyme in I to 

 1,000,000 dilution reacted with homologous immune serum and wdth 

 immune sera against pneumococcal types 2, 20 and 12. Absorption with 

 leuconostoc cells growm in sucrose broth removed from all reactive 

 antisera the capacity to react with dextran of culture source. When 

 bacteria were grown in glucose broth they failed to absorb the specific 

 antibody. Similarly, absorption with penumococci removed the dextran 

 reacting capacity from homologous antipneumococcal sera. 



Enzyme-sucrose mixtures of strains B.M. and O, like the culture 

 fluids of those strains, had only slight capacity to react with type 12 

 antipneumococcal sera in comparison to their capacity to react with 

 types 2 and 20 antipneumococcal sera; whereas the enzyme-sucrose 

 mixtures of strains B.C. and K, like the culture fluids of those particular 

 strains, had as great a capacity to react with the type 12 as with types 2 

 and 20 antiserums. 



Hehre (1945) reported that enzyme preparations from Bacillus N9 

 of plant origin and Streptococcus salivarius isolated from a human 

 throat catalyzed the synthesis of levulan polysaccharide from sucrose. 

 These were found to be serologically active (Hehre, et ah 1944). These 

 two different bacteria yielded identical polysaccharides. They were 

 laevo-rotatory before and after acid hydrolysis, and yielded 96 to 97 per 



