Immunochemistry of the pneumococcal types II, V, and VI. III. Tests with derivatives of the specific polysaccharides of types II and VI.

Rebers, P. A. (Rutgers, The State University, New Brunswick, N. J.), E. Hurwitz, M. Heidelberger, and S. Estrada-Parra. Immunochemistry of the pneumococcal types II, V, and VI. III. Tests with derivatives of the specific polysaccharides of types II and VI. J. Bacteriol. 83:335-342. 1962.-The type-specific pneumococcal polysaccharides, S II and S VI, were oxidized with periodate, and the capacity of the derivatives for precipitation by antibodies and adsorption by erythrocytes was studied. The derivatives were further modified by reduction, oxidation, and condensation with urea. Oxidation of S VI with periodate reduced its precipitation of homologous antibodies much less than did similar treatment of S II. About one-half of the components are attacked in both cases, but in S II, glucuronic acid end groups, the chief determinants of specificity, are destroyed by periodate, whereas in S VI, the structures responsible for specificity are either less affected or yield derivatives with almost as much affinity for antibody as the original polysaccharide. S II and S VI are not adsorbed by washed rabbit or human erythrocytes, but their periodate-oxidized derivatives are readily taken up, presumably owing to their newly formed reactive aldehyde groups, giving high titers in passive hemagglutination. The method should be applicable to other polysaccharides which do not adsorb readily on red cells.