Evaluation of polyclonal antibodies raised in rabbits against dengue NS1 antigen

Dengue, a vector-borne disease caused by the dengue virus (DENV), is spread by Aedes mosquitoes like, Aedes aegypti and Aedes albopictus. In the absence of antiviral drugs or vaccines, dengue prevention is centered on mosquito vector control. Laboratory confirmation of DENV infection is essential to offer the appropriate clinical care. The non-structural protein-1 (NS1) antigen of the virus, in its secretory form, is being employed as a diagnostic marker to identify active dengue infection in humans and mosquito vectors. Commercial dengue NS1 ELISA kits use monoclonal antibodies to detect the NS1 antigen. However, polyclonal antibodies offer several advantages over monoclonal antibodies in terms of shorter production time, lower cost and high stability. Therefore, in the present study, we have raised Rabbit Polyclonal Antibodies against the Dengue NS1 antigen (RPAD) and evaluated their sensitivity and specificity in detecting dengue virus. The RPAD were tested against commercial recombinant dengue virus-2 NS1 antigen (rDNS1Ag) by standardized ELISA and Western Blot assays. Further, the sensitivity of RPAD was checked against the NS1 antigens of different serotypes of DENV. The specificity of RPAD towards the NS1 antigens of other flaviviruses was also tested. The RPAD demonstrated consistent immunoreactivity toward recombinant NS1 antigens of all four dengue virus serotypes in ELISA and Western blot assays, with minimal cross-reactivity to NS1 antigens of other flaviviruses. These findings indicate the potential utility of RPAD as a laboratory reagent for NS1 antigen detection, warranting further validation using clinical samples and field-collected mosquito vectors.