Inhibition ELISA as a putative tool for the identification and quantification of meningococcal A and X polysaccharides at various stages of vaccine development.

The multivalent glycoconjugate vaccines against Neisseria meningitidis are extremely high-priced for the developing world. The high cost is due to the manufacturing set-up required to produce an effective vaccine and other inflators like complex production steps including the production and purification of the polysaccharide and consequently its conjugation with a protein and finally formulating the finished multivalent product. There is an urgent need for assays which are simple, precise, can be applicable at multiple steps and contribute in reducing the overall manufacturing cost, thereby making the vaccines more equitable to the developing world. WHO recommends serological tests for polysaccharide identification and quantitation at different stages of conjugate vaccine production. We report development of inhibition ELISAs for the identification and quantification of N. meningitidis serogroup A (MenA) and N. meningitidis serogroup X (MenX) polysaccharides (PSs) in samples from stage of cell banking till production of finished product. The method was qualified on various parameters such as specificity, intermediate precision, sensitivity and accuracy. Our results provide a proof of concept for the use of an inhibition ELISA as a common tool for the identification and quantification of PS at various stages of vaccine development and manufacture.