Production and degradation of serogroup B Neisseria meningitidis polysaccharide.

Polysaccharide produced from cultures of serogroups A, B, and C Neisseria meningitidis was assayed by the serogroup-specific hemagglutination inhibition (HAI) test. The polysaccharide produced by all serogroups was found to increase during the exponential phase of growth. For serogroups A and C, the HAI activity was stable during the stationary phase; for serogroup B, however, the HAI decayed rapidly. The degradation of the serogroup B polysaccharide was not caused by enzymatic degradation, but was due to acid accumulation in the culture medium. The large-molecular-size serogroup B polysaccharide was stabilized by increasing the buffering capacity of the medium, which also increased the yield of this antigen.