Dengue NS1 Antibodies drive Immune Complex Formation, Hyperglycaemia and systemic pathology in a murine NS1 plasmid challenge model

Abstract

Dengue virus (DV) NS1, a secreted virotoxin and key pathogenic factor, can trigger immune responses with poorly understood long-term effects. This study assessed immunopathology in mice administered with DV NS1 plasmid DNA via intraperitoneal (IP), intramuscular (IM), or intravenous (IV) route for DV serotypes 1-4. IP delivery caused the most pronounced effects, including elevated AST/ALT and GRP78 levels, hyperglycemia, and altered organ weights, with DV4 NS1 showing the strongest hepatic damage. Despite serum NS1 antigen being undetectable, mice developed strong NS1-specific antibodies (Abs) and immune complexes. Liver histology revealed degeneration and immune cell depletion. DV NS1 plasmid DNA was detected in liver tissue, but not RNA. DV could infect and replicate in murine pancreatic beta cells. In liver cells, DV increased GAPDH expression, while NS1-Ab-positive serums reduced it. Findings indicated that NS1-specific Abs, not the antigen, drove immune-metabolic dysfunctions, emphasizing the need to evaluate Ab-mediated effects in dengue pathogenesis. Significance StatementDengue virus (DV) remains a leading tropical pathogen, yet the long-term effects of its secreted virotoxin NS1 are incompletely understood. Using a murine model, we demonstrated that NS1 plasmid DNA administration drove systemic and organ-specific pathology. Serotype-specific differences in immune responses, biochemical alterations, and histopathological changes underscored NS1s complex role in disease severity. Elevated immune complexes and liver enzyme profiles highlighted mechanisms of immune modulation and hepatic injury, key features of dengue, while increased serum glucose and GRP78 levels pointed to early markers of diabetes onset. These findings provide foundational evidence that NS1- and NS1 antibody-mediated pathways link dengue pathogenesis with metabolic dysfunction, offering critical insights into host-pathogen interactions and comorbidity development.