Self-adjuvanting Ebola virus-like particles that incorporate a cellular interferon-inducing domain

Abstract

Ebola virus-like particle (EBOV VLP) vaccines composed of glycoprotein (GP), matrix protein VP40, and nucleoprotein (NP) typically require multiple adjuvanted doses to elicit protection. To enhance immunogenicity and mimic live virus infection, retinoic acid-inducible gene I (RIG-I) N-terminal CARD domains (2CARD), which can trigger type I interferon (IFN) production, were fused to the NP C-terminal domain (NPCT). VLPs incorporating 2CARD-NPCT, GP and VP40 triggered a MAVS-dependent IFN response upon infection of A549 cells. In mice, a single immunization elicited robust antibody responses persisting for at least 20 weeks and provided complete protection against lethal challenge with mouse-adapted EBOV, whereas standard VLPs failed to do so. Furthermore, the system successfully incorporated Mycobacterium tuberculosis antigens via fusion to NPCT or VP40. The findings demonstrate that incorporating 2CARD overcomes the low immunogenicity of standard VLPs. This modified EBOV VLP system serves as a potent, single-dose self-adjuvanting vaccine platform adaptable for various non-EBOV antigens.