A New Type of Phase Variation in the 103 Race of Shigella Paradysenteriae

[摘要] Five antigenically identical strains of Shigella paradysenteriae 103 are described. They differ from most 103 strains in possessing a group antigen indistinguishable from that of the X race. The X antigen was the only antigenic component of one phase of the cultures, and was combined with 103 specific antigen in another phase. The X antigen decreased in quantity over a period of 4 years, being gradually replaced by 103B antigen. Some possible interpretations of this phenomenon and its application to the theories of antigenic structure and classification of the Flexners are discussed.

[学科分类] 生物科学（综合）