Characterization of saccharide-CRM197 conjugate vaccines.

A seven-valent pneumococcal conjugate and a Group C Meningococcal conjugate are at the late stage of development. Clinical studies have demonstrated the efficacy and safety of these vaccines and licensure of these vaccines will be approved in the near future. Several new techniques have been proposed for characterizing polysaccharide-protein conjugates and their production intermediates. We are evaluating some of these new techniques, particularly NMR and MALLS, to determine whether or not they provide useful information for conjugate production. In the production of polysaccharide protein conjugates, the degree of saccharide activation, location of activation site, and the molecular weight of activated saccharides may typically be determined. In our evaluation, techniques such as NMR and MALLS may have a limited applicability for testing polysaccharides and activated saccharides.