真菌の免疫学的活性物質の研究 : 1.全身性真菌症(Coccidioidomycosisおよびhistoplasmosis)における皮内反応抗原の化学的性状

抄録

The active principle responsible for delayed type of skin reaction in mycotic infections has been thought to be a polysaccharide. However, preparations of immunologically active polysaccharides derived from culture filtrates or organisms were not homogeneous and always contained significant amounts of nitrogen. In this study, therefore, the chemical property of skin test antigens isolated from coccidioidin and histoplasmin has been reexamined carefully by several methods. TCA precipitates and deproteinized ethanol precipitates obtained from coccidioidin contained 12.53% N and 6.13% N, respectively. Both fractions were skin test active. Pronase or trypsin trestment of both fractions markedly reduced their delayed skin test activities in infected guinea pigs. Whereas 0.1γ of the original polysaccharide fraction was equivalent to the standard dose, 1,000γ of the pronase treated"polysaccharide"was required to give a skin reaction of approximately same size. Furtheemore, skin test activity of histoplasmin and histoplasmin polysaccharide was also reduced by the treatment with pronase. When coccidioidin polysaccharide was injected with complete Freund's adjuvant into foot pads of guinea pigs, this fraction was capable of sensitizing animals for delayed skin reaction, but the pronase treated polysaccharide failed to sensitize animals. Although a homogeneous skin test active substance has not been isolated in this work, these results strongly suggest that the active principle of coccidioidin and histoplasmin is protein.