Commercial Enzyme-Linked Immunosorbent Assay Kit Is Useful for Detection of Recombinant and Secretory Nonstructural-1 Protein Antigen of Dengue Virus.

Dengue is a mosquito-borne tropical disease, caused by the Dengue virus (DENV). It has become a severe problem and is a rising threat to public health. In this study, we have evaluated commercial Merilisa i Dengue NS1 Antigen kit (Meril LifeSciences India Pvt. Ltd.) to detect recombinant dengue virus 2 NS1 antigen (rDNS1Ag) and secreted forms of NS1 antigen (sDNS1Ag). To determine the detection limit of the kit, 100 nanogram (ng) to 0.001 ng rDNS1Ag was tested. The sensitivity and specificity of the kit was determined using recombinant NS1 antigens of all serotypes of DENV and other flaviviruses. For testing sDNS1Ag, the culture supernatant of the Vero cell lines infected with DENV-2 was tested. Further, a spiking experiment was carried out to check the sensitivity of the kit to detect rDNS1Ag in the pools of mosquitoes. It was observed that the kit can detect the rDNS1Ag at 1 ng concentration. The kit was sensitive to detect NS1 antigen of DENV-1, DENV-2 and DENV-3 serotypes and specific for detection of only DNS1Ag as it did not cross-react with NS1 antigen of flaviviruses. The kit was sensitive to detect rDNS1Ag in the mosquito pools as well. In addition, the kit was able to detect the sDNS1Ag in Vero cell culture supernatant. Overall, we observed that the Merilisa i Dengue NS1 Ag kit is sensitive and specific for the detection of DNS1Ag both in recombinant and secretory forms.