Development of a Multi-Plex Electrochemiluminescent Assay for the Detection of Serum Antibody Responses to Meningococcal Conjugate Vaccines

Abstract

Neisseria meningitidis is a gram negative diplococcal bacterium. Worldwide, N. meningitidis is the leading cause of bacterial meningitis and sepsis, with five serogroups (A, B, C, Y, and W-135) responsible for the majority of the disease. Multivalent (A, C, Y, and W-135) polysaccharide and conjugate vaccines have been licensed in the United States and elsewhere and are widely available. We have developed a multi-plexed electrochemiluminescent assay to quantitate serum antibody responses to meningococcal polysaccharides A, C, Y, and W-135 to allow for rapid evaluation of licensed and investigational vaccines. A 96-well plate containing a carbon electrode arrayed with polysaccharides A, C, Y, and W-135 on separate spots within each well has been developed for simultaneous detection of polysaccharidespecific antibodies in serum samples from vaccinated individuals. The assay conditions were optimized using the antimeningococcal serogroup A/C reference serum pool, CDC 1992 (NIBSC 99/706), through evaluation of plate types, coating polysaccharide concentrations, and blocking and serum diluent buffers. Comparison of single and multi-plex assays demonstrated the sensitivity, specificity, and speed of the multi-plex format for the quantification of serum antibody responses to N. meningitidis polysaccharides A, C, Y and W-135.