The levan polysaccharides synthesized from sucrose by a spore-forming bacillus of plant origin and by a strain of Streptococcus salivarius were proved to be serologically reactive and serologically similar substances. The levans gave both precipitation and complement fixation with antiserums produced by immunization with either the streptococcus or the bacillus which had been grown in media containing sucrose, and also reacted with some samples but not with most type 20 antipneumococcus serums.
The carbohydrate in the culture medium was an important factor. The serologically reactive levans were produced in abundant amount in broth containing sucrose or raffinose whereas none could be found in cultures grown with 8 other sugars. Similarly, antiserums reactive with the levans were readily produced by immunization with suspensions of either the bacillus or streptococcus which had been grown in sucrose media but not by immunization with the same bacteria grown in glucose media.
Aid was received from the Sugar Research Foundation, Inc.