Immunological Studies of Polysaccharides of Encapsulated Bacillus. III. Active Sensitization with Polysaccharide from B. rhinoscleromatis.

Abstract

Attempts to produce active sensitization of guinea pigs through the use of killed cultures of different Gram negative microorganisms, have been, so far, uniformly unsuccessful. Since the development of hypersensitivity in infections caused by certain Gram negative bacteria is well established, it appears inconceivable that these bacteria should be incapable of causing active sensitization under experimental conditions. The failure in this respect might be attributable either to insufficient dosage or to unsuitable preparations of the antigen. In the present work it will be shown that the specific polysaccharide derived from a Gram negative, capsulated strain of B. rhinoscleromatis may act as an efficient antigen in bringing about active sensitization of guinea pigs.

Two lots of the specific polysaccharide were used in this experiment. The first lot of the substance (Fraction SI 1 ) was prepared by a 30 minutes'hydrolysis of a watery suspension of bacterial cells in the presence of one percent acetic acid which was followed by alcoholic precipitation. The second lot (Fraction SIII 1 ) was obtained by a similar process; 0.5% potassium hydroxide was used instead of acetic acid. From chemical analysis it was found that both lots of the substance represent polysaccharide fractions of the bacterial cell showing identical properties and similar serological behavior when tested against rabbit sera prepared by immunization with killed cultures of B. rhinoscleromatis.