Pilot-scale production of group a and group C meningococcal polysaccharide immunogens.

Methods have been developed for the pilot-scale production of group A and group C meningococcal polysaccharide immunogens based on the meningococcal strains, the medium, and the basic processing procedures used by Gotschlich et al. Physical and chemical assays on the final products obtained on a pilot-scale level indicate that these purified polysaccharides are entirely comparable to the Gotschlich preparations which proved to be immunogenic in man.

Preparation of cholera vaccines by fluorocarbon extraction of cholera Vibrio suspensions.

Experimental cholera vaccines were prepared from suspensions of cholera vibrios which were extracted with Genetron-113. These vaccines, when compared with a control preparation which was not treated with Genetron, had a lower nitrogen content and were less toxic for mice but were as effective in protecting mice against infection and in inducing agglutinating and vibriocidal antibody responses in rabbits. This procedure may permit the preparation of cholera vaccines with a higher antigenic content without the corresponding increase in toxic reactions.

Freeze-drying various strains of Shigella.

Of six candidate strains of Shigella prepared in Brain Heart Infusion broth as freeze-dried vaccine, low survival rates were obtained with two of the most promising strains. Survival rates with these two strains were increased to acceptable levels when the organisms were suspended in a medium consisting of 8.2% sucrose, 0.