Abstract
Study was made to clarify the experimental conditions for the capsular polysaccharide of Klebsiella pneumoniae (CPS-K) to exhibit maximum adjuvant effect on antibody production to bovine serum albumin (BSA) in mice. To obtain the maximum primary antibody response and also the strongest priming for a secondary response to BSA, 1000μg of CPS-K had to be injected intramuscularly into the same or adjacent site of BSA injection within the period of 1hr before to 6hr after the BSA injection. The optimum amount of BSA giving the maximum antibody response and also the strongest priming under these experimental conditions was 15mg. In mice thus primed, an extremely high secondary response was induced by injecting 0.5mg of BSA 30 days after the initial injection. The minimum amount of CPS-K, to exhibit a strong adjuvant action, was 100μg, which was equal to the minimum amount to induce immunologic paralysis to a homologous antigen. Extremely large amounts, such as 100 to 300mg per mouse of BSA, were also strongly immunogenic when injected together with paralyzing doses of CPS-K. In vitro admixture of BSA and CPS-K before injection did not strengthen adjuvant action of CPS-K. Alum-precipitated BSA mixed with CPS-K was not more immunogenic than native BSA mixed with CPS-K. Addition of Freund's complete adjuvant to an injection of BSA and CPS-K mixture did not enhance the adjuvant effect of CPS-K.
