PEP-R619W Differentially Modulates IFN-I Signaling to Enhance Antiviral Immunity 2260034

Abstract Introduction Persistent Type I interferon (IFN-I) signaling sustains chronic viral infection by inducing expression of negative regulators that suppress immune activation and drive T cell exhaustion. The autoimmune-associated variant PEP-R619W changes immune signaling, yet its impact on the IFN-I-driven pathway remains unclear. We hypothesized that PEP-R619W differentially regulates IFN-I signaling, thereby modulating antiviral immunity. Methods Using CRISPR/Cas9-engineered PEP-R619W C57BL/6 mice, we analyzed protein and cytokine expression by flow cytometry, IFN-signaling via phospho-flow (pSTAT1/pSTAT4), and interferon-stimulated genes (ISGs) by real-time PCR following IFN-β stimulation. Results PEP-R619W Dendritic cells (DCs) exhibited increased pSTAT1 and ISG expression with reduced SOCS3, indicating sustained IFN-I signaling and decreased negative regulation. Conversely, PEP-R619W effector CD8 T cells showed reduced pSTAT1/pSTAT4 expression, but maintained ISRE and GAS driven ISG induction, despite increased Usp18. This suggests preferential attenuation of chronic IFN-I signaling with preserved transcriptional responsiveness. Functionally, these cells produced higher levels of IFN-γ and Granzyme B, particularly in response to the minor gp276-284 epitope of LCMV-cl13, reflecting enhanced effector function and reduced exhaustion. Conclusion PEP-R619W modulates IFN-I signaling in a cell-type-specific manner. It enhances DC activation while preserving the function of CD8 T cells as effector cells. This prevents immune dysfunction and enhances viral clearance. Our data highlight a novel mechanism by which the autoimmune-associated allele, PEP-R619W, rewires sustained IFN-I signaling in a cell-type-specific manner, uncovering potential therapeutic avenues for chronic virus infection. Funding Source CBID CoBRE Research Grant (KU)-P20GM113117 Topic Categories Immune Response Regulation: Molecular Mechanisms (IRM)