Establishment of an IFNAR2 Knockout Pig Model for Severe Dengue-Like Pathology.

Dengue virus (DENV) can cause severe dengue characterized by plasma leakage, hemorrhagic manifestations, and multi-organ dysfunction. Current animal models, particularly AG129 mice, inadequately recapitulate human vascular pathology due to neurotropic confounding and reliance on mouse-adapted strains. To address this translational gap, we generated interferon alpha/beta receptor subunit 2 (IFNAR2) knockout (KO) pigs via CRISPR/Cas9 gene editing and somatic cell nuclear transfer. Four KO piglets were challenged intradermally with a DENV serotype 4 clinical isolate non-pathogenic in AG129 mice. One animal died at 7 days post-infection, exhibiting pleural effusion, ascites, and severe hemorrhagic lesions across multiple organs. Sustained viremia (10⁵·¹ copies/mL) was accompanied by marked cytokine elevation (TNF-α 255.1 pg/mL; IL-12p40 288.1 pg/mL), biochemical evidence of hepatocellular injury (AST 827.9 U/L) and renal dysfunction. Histopathology revealed widespread vascular endothelial necrosis without CNS involvement, closely resembling human severe dengue vasculopathy. The three remaining KO pigs showed only transient low-level viremia without severe disease. Although limited to a single severe case, these findings provide proof-of-concept that IFNAR2 KO pigs can recapitulate hallmark features of human severe dengue, offering a physiologically relevant large animal platform for pathogenesis research and therapeutic evaluation.