Measurement of antibodies to pneumococcal polysaccharides with Luminex xMAP microsphere-based liquid arrays

The 23 valent pneumococcal polysaccharide vaccine (PPV) is often used to assess an individual's ability to produce antibodies to polysaccharides. The Luminex xMAP microsphere-based liquid array system, when applied to the determination of antibodies to pneumococcal polysaccharides (PnPs), allows for the antibody response to the 23 serotypes to be determined simultaneously. Multiplexing saves considerable time and expense over the traditional method of testing each PnPs serotype individually by the enzyme-linked immunosorbent assay (ELISA). This chapter describes methods for (a) conjugation of poly-L: -lysine (PLL) to PnPs, (b) coupling of PnPs-PLL conjugates to Luminex microspheres, and (c) a multiplex Luminex assay for the measurement of serotype-specific IgG concentrations to pneumococcal serotypes.