Model-Guided Engineering of NS1-Truncated Influenza OP7 Particles with Enhanced Interferon-Mediated Antiviral Activity

Defective interfering particles (DIPs) represent promising antivirals against influenza A virus (IAV), yet strategies to further enhance their antiviral activity remain largely unexplored. Here, we engineered a next-generation “OP7” DIP by truncating the viral interferon (IFN) antagonist non-structural protein 1 (NS1) to enhance IFN-mediated antiviral activity. A previously validated mathematical multiscale model predicted that loss of NS1 function would enhance antiviral activity, providing a mechanistic rationale for this design. We engineered “OP7-trNS1” DIP, established a cell culture-based production process yielding infectious virus-free material, and evaluated its antiviral activity in human lung epithelial cells in vitro . OP7-trNS1 inhibited IAV replication by approx. two orders of magnitude more effectively than the parental OP7 DIP while inducing a stronger IFN response, consistent with the model predictions. Together, these findings demonstrate that reducing viral IFN antagonism is a viable strategy for rationally enhancing DIP antiviral activity and establish OP7-trNS1 as a promising candidate for further preclinical development.