8/ Compared to monovalent EV-D68 vaccine controls, multivalent LNP induced a higher systemic type I IFN response and a reduced neutralizing antibody response. Meanwhile, multivalent LION mitigated the former and maintained the latter, providing superior protection from challenge. Our conclusion? Restricted biodistribution of repRNA is crucial for reducing reactogenicity and enabling adaptive immune responses to multivalent repRNA vaccination. Stay tuned for further developments in our research!

7/ For multivalent repRNA scenarios, the innate immune system responds to larger total repRNA doses. We hypothesized that this might impede the adaptive response to the relatively smaller monovalent repRNA dose in the mixture. To test this, Taishi analyzed the systemic innate and neutralizing antibody response to enterovirus D68 #EVD68 induced by a trivalent vaccine against RSV, Flu, and EV-D68.

6/ Alongside reactogenicity, we explored whether such systemic responses could affect adaptive immune responses. Despite systemic innate response differences, no variances in binding antibody responses were detected between LNP or LION delivered repRNA vaccines.

5/ Our data in Mx1/GFP mice suggest the liver is the main contributor to the systemic response to LNP/repRNA.

4/ The systemic response was his next focus. He found significant LNP-induced weight loss and high levels of circulating pro-inflammatory cytokines similar to those recently reported by Barmada et al https://twitter.com/anisbarmada/status/1654570291601764354?s=46&t=vbGjOQoWpKGJUKPs7BAxNg. LION, in contrast, caused minimal weight loss and systemic innate response

3/ Given the shared delivery site between LION and LNP (muscle), he next evaluated local innate responses in the injection site. He discovered distinct phenotypes, including innate gene regulation and infiltrating immune cells.

2/ As repRNA clinical trial results began to surface, we noticed a difference in dose-dependent reactogenicity. LNP trials reported grade 3 adverse events at lower doses than our findings. With broad biodistribution and systemic innate responses reported for LNP/repRNA, Taishi hypothesized LION might mediate differential biodistribution and systemic response. His research using mice showed that LION stayed primarily at the local injection site, while LNP distributed more widely.