IMMUNIZATION OF HUMAN SUBJECTS WITH THE SPECIFIC CARBOHYDRATES OF TYPE III AND THE RELATED TYPE VIII PNEUMOCOCCUS 1

Abstract

High titers of antibodies against the homologous type were demonstrated regularly in human subjects following the subcut. injection of 1 mgm. of a highly purified, type-specific carbohydrate of Pneumococcus Type VIII. Various preparations of the Type III pneumococcus polysaccharide, given in the same manner, produced antibodies for the homologous type with less regularity and in lower titers. Occasional subjects injected with Type III or with the related Type VIII pneumococcus carbohydrate developed antibodies against pneumococci of the heterologous but related type. Such cross-immunity, however, was less frequent and of a lower grade than that encountered either in animals immunized with the whole organism or in human patients recovering from pneumonia due to these types of pneumococcus.