A monoclonal antibody to DIII E protein allowing the differentiation of West Nile virus from other flaviviruses by a lateral flow assay

West Nile Virus (WNV) belongs to the Flaviviridae family, genus Flavivirus, which includes other emerging arthropod-borne viruses (arboviruses) pathogenic for animals and/or humans. West Nile Virus is a genetically diverse RNA virus with at least 7 different recognized lineages. Following its recent introduction and subsequent expansion to the Americas, WNV is currently one of the most widely spread arboviruses in the world having recently re-emerged in the Mediterranean basin, Central and Eastern Europe. Laboratory tests are essential to confirm WNV infection and monoclonal antibodies represent useful tools for the development of diagnostic assays. A monoclonal antibody, 1D11, recognizing an epitope in the domain III of the envelope glycoprotein of WNV, was selected for this study. Its suitability to detect a range of WNV variants representative of its whole genetic range, and to differentiate it from other flaviviruses and arboviruses, was assessed by means of an immunochromatographic assay in an LFA format. A panel of cell culture supernatants infected with 9 different WNV isolates representing a wide range of genetic lineages, and 16 non-WNV arboviruses, including flaviviruses closely related to WNV, were tested. The mAb correctly detected all WNV strains, and did not react with any of the non-WNV arboviruses.