PT  - JOURNAL ARTICLE
AU  - Randall Toy
AU  - M. Cole Keenum
AU  - Pallab Pradhan
AU  - Katelynn Phang
AU  - Patrick Chen
AU  - Chinwendu Chukwu
AU  - Anh Nguyen
AU  - Jiaying Liu
AU  - Sambhav Jain
AU  - Gabrielle Kozlowski
AU  - Justin Hosten
AU  - Mehul S. Suthar
AU  - Krishnendu Roy
TI  - TLR7 and RIG-I dual-adjuvant loaded nanoparticles drive broadened and synergistic responses in dendritic cells and boost cellular immunity in influenza vaccination
AID  - 10.1101/2020.07.17.207423
DP  - 2020 Jan 01
TA  - bioRxiv
PG  - 2020.07.17.207423
4099  - http://biorxiv.org/content/early/2020/07/17/2020.07.17.207423.short
4100  - http://biorxiv.org/content/early/2020/07/17/2020.07.17.207423.full
AB  - Although the existing flu vaccines elicit strong antigen-specific antibody responses, they fail to provide effective, long term protection – partly due to the absence of robust cellular memory immunity. We hypothesized that co-administration of combination adjuvants, mirroring the flu-virus related innate signaling pathways, could elicit strong cellular immunity. Here, we show that the small molecule adjuvant R848 and the RNA adjuvant PUUC, targeting endosomal TLR7s and cytoplasmic RLRs respectively, when delivered together in polymer nanoparticles (NP), elicits a broadened immune responses in mouse bone marrow-derived dendritic cells (mBMDCs) and a synergistic response in both mouse and human plasmacytoid dendritic cells (pDCs). In mBMDCs, NP-R848-PUUC induced both NF-κB and interferon signaling. Interferon responses to co-delivered R848 and PUUC were additive in human peripheral blood mononuclear cells (PBMCs) and synergistic in human FLT3-differentiated mBMDCs and CAL-1 pDCs. Vaccination with NPs loaded with H1N1 Flu antigen, R848, and PUUC increased CD8+ T-cell populations in the lungs and antigen-specific T-cell populations in the spleen, and enhanced antigen-specific T cell immunity. Our results demonstrate that simultaneous engagement of TLR7 and RIG-I pathways using particulate carriers is a potential approach to improve cellular immunity in flu vaccination.Competing Interest StatementThe authors have declared no competing interest.