The use of low and high binding ELlSA plates in the determination of cholera antitoxin antibodies

Abstract

Sera from an immunogenicity study of killed oral cholera vaccine was tested in high and low binding Elisa plates. High binding plates yielded 5 to 7-fold higher prevaccination IgG antitoxin titres and about 3-fold higher post-vaccine antitoxin titres, but lower cero-conversion rates (39% for high and 68% for low binding plates) when they were compared with low binding plates, because the pre-vaccine titres were relatively higher than the post-vaccine titres. The high titre serum, being used as a standard control serum in each ELISA plate, did not detect the problem. We suggest using lowbinding plates when carryng out ELlSA assays for cholera antitoxin antibodies.