Effect of Pneumococcus Type III Specific Polysaccharide on Sedimentation of Blood Cells

Abstract

During the course of experiments with the specific polysaccharide prepared from a type III strain of pneumococcus by the method of Avery, Kendall, and Scherp, it was noted that this material greatly increased the sedimentation fate of titrated human blood. This initial finding has been confirmed, and additional observations have been made, which we desire to present in a preliminary paper. The effect of the S III on the sedimentation rate of blood cells can be demonstrated with heparinized or defibrinated blood, as well as with citrated blood. The effect of concentration of the S III on the sedimentation rate of citrated human blood is indicated by the data in Table I. The mixtures of blood and S III were drawn up in tubes of 2 mm. bore to a height of 200 mm., and the sedimentation read as the height of the clear plasma. A carbohydrate substance isolated from a mucoid variant of B. coli by C. Lawrence of this laboratory had a similar effect in increasing the sedimentation rate of blood cells. Gelatin acted in the same way, as did gastric mucin, but to a degree much less pronounced than did the specific polysaccharide of the pneumococcus. Glucose in concentrations up to 1% had no appreciable effect on the phenomenon in question. When mixtures of the S III of the pneumococcus and homologous antiserum are allowed to stand for 15 minutes, and are then'added to blood, the increase in sedimentation rate is markedly diminished, as is shown in Table II. When 1 mg. of the specific polysaccharide was mixed with 1 cc. of blood, the color of the mixture darkened sooner than the control. On shaking the darkened blood, the color was restored to a bright red, only to darken again before the control.