Abstract
Previous findings 1 suggest that polysaccharides prepared from various cultural types of Corynebacterium diphtheriœ are group-specific. It seemed of interest to determine whether polysaccharides of similar nature could be prepared from common diphtheroids.
Stock cultures of C. hofmanni, obtained from the London Type-Culture Collection, and C. xerosis, isolated from the conjunctiva of a patient with dacryocytitis in the Peiping Union Medical College Hospital, were employed for this study. Both organisms are nonpathogenic for either guinea pigs or Chinese hamsters and their staining and biochemical reactions are typical for these organisms with the exception that C. xerosis failed to ferment saccharose. The growing of the organisms and the method of preparing the polysaccharides were the same as those reported previously 1 except that only alkali was employed for hydrolysis. The yield of polysaccharide for both organisms was small, the amount being equal to 1 to 2% of the dried weight of organisms. Incidentally it might be stated that this figure is fairly representative of the yield of all polysaccharides prepared from the corynebacterial organisms thus far studied. The polysaccharides obtained from both organisms were white amorphous powders, readily soluble in saline in a concentration of 0.5%, gave strong Molisch reaction, exhibited none of the usual reactions for protein, and did not reduce Fehling's solution.
In serological tests the polysaccharide of C. xerosis was found to react equally with all sera prepared against the various cultural types of C. diphtheriœ; these included strains of intermediate, of gravis and of mitis. Precipitin titers (1:100,000) similar to those obtained with homologous polysaccharides were found. On the other hand, the polysaccharide of C. hofmanni, even in concentration of 1:1000, reacted weakly or not at all with the same sera.
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