Characterising Innate Immune Evasion by Dengue Virus Non-Structural Proteins in Nigerian Genotype Backgrounds: Towards Broadly Protective Immunisation Strategies

Dengue virus employs multiple non-structural (NS) proteins to antagonise innate immune signalling pathways, including NS2B-3 protease-mediated cleavage of STING and NS4A/4B interference with JAK-STAT signalling. The efficiency of these evasion mechanisms may vary across dengue serotypes and genotypes, with important implications for vaccine design in regions like Nigeria where serotypes 1, 2, and 3 co-circulate. This study characterises innate immune evasion activities of NS proteins from Nigerian dengue strains and uses this mechanistic data to inform broadly protective immunisation strategies. Full-length NS1, NS2B-3, NS4A, NS4B, and NS5 gene sequences will be recovered from 60 dengue-positive clinical isolates from Lagos, Oyo, and Edo states, representing the three circulating serotypes. Recombinant NS proteins will be expressed in HEK293T cells, and their capacity to antagonise IFN-beta induction and STAT1 phosphorylation will be quantified by luciferase reporter assays and Western blotting. Comparative analysis across serotypes and against Asian dengue reference strains will identify Nigerian-specific evasion phenotypes. Epitopes within NS proteins that elicit cross-reactive T cell responses in convalescent Nigerian donor peripheral blood mononuclear cells will be mapped by ELISpot assay. A multi-serotype T cell-targeting vaccine construct incorporating Nigerian-lineage NS epitopes will be designed in silico and immunogenicity predicted using population-specific HLA frequency data. This study produces original mechanistic and vaccinological insights tailored to Nigerian dengue diversity, advancing theoretical frameworks for dengue cross-protection. Keywords: dengue virus, innate immune evasion, NS proteins, Nigeria, cross-protective vaccine