Immunization of rabbits with type II pneumococcal polysaccharide

Humoral immune response in chinchillas to the capsular polysaccharides of Streptococcus pneumoniae

Vaccines made from the capsular polysaccharides of Streptococcus pneumoniae have been shown to reduce the incidence of pneumococcal disease in certain populations and have recently been evaluated for their ability to elicit protection against experimental pneumococcal otitis media in a chinchilla model. In this study, chinchillas were vaccinated with a dodecavalent preparation of pneumococcal capsular polysaccharides (PCP) to obtain more information on the immunogenicity of these polysaccharide antigens. All 12 PCP types elicited an antibody response, but the optimum PCP dose and the kinetics of the antibody response varied among types. Immunological paralysis was demonstrated with an immunogenic dose of PCP after primary immunization with a large PCP dose (25 micrograms or more). Pertussis vaccine acted as neither an immunoadjuvant nor an immunosuppressant in the serum antibody response to type 7F PCP in chinchillas.

Polysaccharide in delayed hypersensitivity. I. Pneumococcal polysaccharide as inducer and elicitor of delayed reactivity in guinea pigs

A highly purified pneumococcal polysaccharide (Type II SSS) is a very efficient inducer of delayed hypersensitivity in random-bred guinea pigs. The cellular reactivity induced by this polysaccharide administered subcutaneously in complete Freund's adjuvant is of "tuberculin type"; it increases in intensity with time after the sensitizing injection, as judged by skin tests, the macrophage inhibition reaction and transfer of reactivity by peritoneal exudate cells. By contrast, the cellular reactivity induced by this immunogen in the absence of mycobacterial adjuvant has the characteristics of "Jones-Mote" reactivity. It is best seen at about 1 wk after sensitization; the reactions are characteristically little indurated and show histologic differences from tuberculin type responses; and the reactive state begins to disappear by 2-3 wk, with the accession of Arthus reactivity. This type of delayed reactivity may be related to an early phase of antibody synthesis.