Antibodies to Type III and Type VIII Pneumococcal Polysaccharides: Evidence for Restricted Structural Heterogeneity in Hyperimmunized Rabbits

Abstract

Two hundred and thirty-two rabbits were hyperimmunized with formalinized type III and type VIII pneumococci in an attempt to elicit the formation of structurally restricted antibody in high yield. Although precipitating antibody to either type III or tyep VIII pneumococcal polysaccharide could be demonstrated in the sera of all immunized rabbits, electrophoretic restriction of the antibody in the λ globulin region could be demonstrated only in a minority of the animals, e.g., in sera from 7% of rabbits immunized with tyep III and from 9% of rabbits injected with type VIII pneumococci. The concentration of type-specific antibody in serum of rabbits showing an electrophoretically-restricted λ globulin region ranged from 3.5 mg to 32 mg/ml of serum. For the isolation of antibodies to S3 or S8 in high yield, a specific immunoadsorbent synthesized from bromoacetylcellulose and a polysaccharide-bovine serum albumin conjugate was developed. Antibodies could be recovered in 75% to 85% yield after being eluted under mild conditions and were found to be 85% to 100% precipitable with the homologous polysaccharides.