Automated type specific ELISA probe detection of amplified NS3 gene products of dengue viruses.

Aim: To apply an automated system of nucleic acid hybridisation coupled with the enzyme linked immunosorbent assay (ELISA) for the type specific detection of amplification products of dengue viruses.

Methods: Non-structural 3 (NS3) gene targets of reference strains of all four dengue and other flaviviruses, as well as dengue patient viraemic sera, were subjected to reverse transcription and polymerase chain reaction using consensus and dengue type specific primers and digoxigenin-11-dUTP label incorporation. The amplification products were detected by biotinylated type specific primers which served as ELISA capture probes bound to streptavidin coated tubes.

Results: Significantly high spectrophotometric absorbance readings were obtained by hybridisation of the consensus and seminested amplification products of all four dengue viruses with their respective capture probes. In contrast, extremely low absorbances were observed for consensus products of Japanese encephalitis, yellow fever, and Kunjin viruses, which served as negative controls. These ELISA data correlated well with agarose gel electrophoresis of dengue type specific amplified products of diagnostic sizes.

Conclusions: The combination of in vitro amplification and antibody based detection offers rapid, type specific, high throughput, and gel-free detection of amplified products of dengue viruses.