Differentiation between vaccine-related and wild-type polioviruses using a heteroduplex mobility assay

A heteroduplex mobility assay (HMA) was developed for intratypic differentiation between poliovirus isolates. The assay is based on polymerase chain reaction (PCR) amplification of a 480 base pair fragment which encodes a variable segment of VP1, followed by denaturation and reannealing of the resulting single strands with those from reference Sabin targets. Mismatches between wild-type and Sabin vaccine templates result in the formation of detectable heteroduplexes of reduced electrophoretic mobility. Poliovirus strains confirmed previously as wild-type or vaccine-like by PCR and sequencing were all correctly identified using the HMA. Mixtures of both wild-type and vaccine-like strains in a single isolate could also be detected using this technique. The results of this study demonstrate that heteroduplex analysis is a simple, rapid, and sensitive means for differentiating between vaccine-like and wild-type poliovirus isolates.