Development of a bead-based multiplex immunoassay for simultaneous quantitative detection of IgG serum antibodies against seven vaccine-preventable diseases.

Serosurveillance and seroprevalence studies should be carried out to monitor vaccine-preventable diseases. Multiplex immunoassay (MIA) systems are useful tools for this purpose, allowing the simultaneous quantitative detection of antibodies in one small serum sample, which presents an advantage over conventional methods, such as enzyme-linked immunosorbent assays (ELISAs). Therefore, we developed a multiplex immunoassay for the measurement of antibodies against seven vaccine-preventable infections (measles, rubella, mumps, tetanus, diphtheria, pertussis and Haemophilus influenza type b (Hib) infection). In our multiplex system, heterologous inhibition generally did not exceed 10%, while homologous inhibition varied between 90 and 98%. The intra- and inter-assay variability was ≤11%. The results of in-house MIA showed satisfactory correlation with commercial ELISAs, with Spearman correlation coefficients from 0.90 to 0.98. At the cut-off values defined for our MIA the serostatus can be determined with high sensitivity (89-100%) and specificity (92-98%). Thus, the developed in-house MIA represents a feasible alternative to conventional ELISAs and could be used for large-scale serosurveillance/seroprevalence studies of vaccine-preventable diseases.