The occurrence of antibodies in rabbit anti-pneumococcus antisera directed against calcium dependent and independent determinants.

Two type specific acidic pol-saccharides from Pneumococci (type III and type VIII) have been used to prepare immuno-adsorbents. The polysaccharides were coupled to Sepharose 4b via a 1,6 hexanediamine spacer and used to isolate two populations of type specific antibodies from rabbit anti-pneumococcus antisera. One population requires calcium to affect interaction with the homologous polysaccharide, while the other population has no such requirement. The isolated antibodies are of the lgG class and are fully active in precipitin assays.