Multiplex PCR-Based Neutralization (MPBN) Assay for Titers Determination of the Three Types of Anti-Poliovirus Neutralizing-Antibodies.

Determination of poliovirus-neutralizing antibodies is an important part of clinical studies of poliovirus vaccines, epidemiological surveillance and seroprevalence studies that are crucial for global polio eradication campaigns. The conventional neutralization test is based on inhibition of cytopathic effect caused by poliovirus by serial dilutions of test serum. It is laborious, time-consuming and not suitable for large scale analysis. To overcome these limitations, a multiplex PCR-based neutralization (MPBN) assay was developed to measure the neutralizing antibody titers of anti-poliovirus sera against three serotypes of the virus in the same reaction and in shorter time. All three anti-poliovirus sera types were analyzed in a single assay. The MPBN assay was reproducible, robust and sensitive. Its lower limits of titration for the three anti-poliovirus sera types were within range of 0.76-1.64 per mL. Different anti-poliovirus sera were tested with conventional and MPBN assays; the results obtained by both methods correlated well and generated similar results. The MPBN is the first neutralization assay that specifically titrates anti-poliovirus antibodies against the three serotypes of the virus in the same reaction; it can be completed in two to three days instead of ten days for the conventional assay and can be automated for high-throughput implementation.