Critical Differences between Pneumococcal Polysaccharide Enzyme ...

CLINICAL AND VACCINE IMMUNOLOGY, Mar. 2006, p. 356–360 1556-6811/06/$08.00⫹0 doi:10.1128/CVI.13.3.356–360.2006 Copyright © 2006, American Society for Microbiology. All Rights Reserved.

Vol. 13, No. 3

Critical Differences between Pneumococcal Polysaccharide Enzyme-Linked Immunosorbent Assays with and without 22F Inhibition at Low Antibody Concentrations in Pediatric Sera Isabelle Henckaerts,1* David Goldblatt,2 Lindsey Ashton,2 and Jan Poolman1 GlaxoSmithKline Biologicals, Rixensart, Belgium,1 and Institute of Child Health, London, United Kingdom2 Received 29 September 2005/Returned for modification 9 November 2005/Accepted 18 January 2006

A comparative study was conducted between two laboratories in order to evaluate the differences between two enzyme-linked immunosorbent assay (ELISA) techniques for the detection of pneumococcal anti-capsular polysaccharide antibodies. One laboratory used an assay including heterologous 22F polysaccharide inhibition, and the other laboratory employed a non-22F reference assay. After conjugate immunization, 30 pediatric post-primary immunization sera with antipolysaccharide concentrations ranging from 1 ␮g/ml. However, at antibody levels of