NMR Assays for Estimating the O-Acetyl Content of Meningococcal Polysaccharide Serogroup A in Quadrivalent Conjugate Vaccine Formulation

The use of multivalent glycoconjugate vaccines has dramatically contributed to reduce the incidence of meningococcal infectious disease. The advanced structural characterization of polysaccharide conjugates leads to enhancements in the quality and control of the products. Here, we report a novel nuclear magnetic resonance (NMR) method to confirm the identity and structural conformity (e.g., O-acetyl content) of saccharide antigens that comprise a licensed tetravalent meningococcal serogroups A, C, W, and Y vaccine. For the first time, the NMR methodology is applied on a formulation (licensed vaccine) containing a large excess of excipient (i.e., sucrose) without analytical sample pretreatment. This work confirms the applicability of a rapid and easy NMR assay on a multivalent conjugate vaccine, which might be extended to other combination vaccines that are already licensed or in clinical development.