Development of an ELISA using recombinant Dengue NS1 constructs to measure antibody titers and predict dengue disease outcome in a pediatric population in India.

The majority of the antibody response in dengue infection targets the structural envelope (E) and membrane (M) proteins of the virus. However, vaccine development is challenging because antibodies against the E protein often show cross-reactivity, leading to antibody-dependent enhancement (ADE) and worsening of disease severity. Non-structural protein 1 (NS1), secreted during the acute phase of infection, has been implicated as a pathogenic factor that contributes to vascular permeability and haemorrhage in severe dengue. In this study, we aimed to investigate the role of NS1 antibodies in disease manifestation. Full-length NS1, along with its N-terminal (NS1A) and C-terminal (NS1B) regions, was expressed and purified to delineate the antibody response against different domains. Serum samples from 102 dengue-positive paediatric patients were analysed for antibody titres against these NS1 constructs using ELISA. Overall higher antibody titres against all three NS1 recombinant proteins were observed in mild cases compared to severe ones with most significant towards NS1A.These findings suggest that antibodies directed against NS1, particularly its N-terminal region, may have a protective role and could serve as a potential correlate of protection in dengue infection.