Enzyme-Linked Immunosorbent Assay for Determination of Human Antibodies to Group C Meningococcal Polysaccharide

To study immunity to meningococcal diseases, investigators need a sensitive, serological technique for measurement of the protective antibodies. Although the well- accepted assay for this purpose is the radioimmunoassay (RIA), it requires expensive equipment and uses potentially hazardous reagents which usually have a short shelf life. The enzyme-linked immunosorbent assay (ELISA) has been reported to be as sensitive and reliable a technique as the RIA. We have developed the ELISA for determination of antibodies to group C meningococcal polysaccharide. A successful method for the indirect coating of polystyrene surfaces with polysaccharide antigen, the biochemical purification of the different reagents used and the various optimal ELISA parameters are described. The results of 90 different human sera tested by the ELISA technique were comparable with RIA results of the same sera, and a significant correlation was obtained (r = 0.86; P < 0.001).