Copyright © 2016 by The American Association of Immunologists, Inc. Protective immunity against intracellular pathogens involves the induction of robust CTL responses. Vaccination with protein Ags establishes such responses only when combined with immune-stimulatory adjuvants. In this study, we compared different adjuvants and identified triphosphate RNA (3pRNA) as especially effective at inducing CTL responses. 3pRNA sensing required IPS-1/MAVS signaling and induced type I IFN in plasmacytoid dendritic cells and macrophages, with the latter being more important for the adjuvant effect. Type I IFN acted on CD11c + cells, especially on CD8a + Batf3-dependent dendritic cells. Vaccination with OVA in combination with 3pRNA protected mice from a subsequent OVA-encoding adenovirus infection in a CD8 + cell-dependent manner and more efficiently than other adjuvants. In summary, 3pRNA is a superior adjuvant for CTL activation and might be useful to facilitate antiviral immunization strategies.
Hochheiser, K., Klein, M., Gottschalk, C., Hoss, F., Scheu, S., Coch, C., … Kurts, C. (2016). Cutting Edge: The RIG-I Ligand 3pRNA Potently Improves CTL Cross-Priming and Facilitates Antiviral Vaccination. The Journal of Immunology, 196(6), 2439–2443. https://doi.org/10.4049/jimmunol.1501958