Variation of type Antigens of Group-B Streptococci

Abstract
When occurring together with the polysaccharide III-antigen the X-antigen displayed a phenotypic variation in vitro, and so did 1 R-strain. Genuine X-straims, and other types as well, seemed to remain unaffected by commonly used laboratory procedures. The hypothesis is advanced that previously described in-vivo variations of these antigens are induced by antibodies against the antigen in question.