Cross-Reactions of Glucose-Containing Polysaccharides in Antipneumococcal Sera: VII. The Precipitation of Type IX Antisera by Isolichenin, and Other Reactions¹

Isolichenin, which consists of α-1, 3- and α-1, 4-linked glucose, partly, at least, in pairs, precipitates type IX anti-pneumococcal sera very strongly at 0°. Quantitative data are given on this reaction and the precipitation of other antipneumococcal sera by isolichenin, other polyglucoses, and natural polysaccharides containing glucose. The data are discussed in terms of a quantitative theory of the precipitin reaction (5) and, where possible, in terms of the linkages of glucose involved.