Figure 6.

Efficacy of RNA-NPs targeting physiologically relevant antigens. (A) C57Bl/6 mice were vaccinated with a single OVA RNA-NP or DC vaccine pulsed with OVA mRNA following OT-I administration before splenocytes were harvested 1 week later for assessment of %antigen-specific CD8⁺ cells. (B) DS red+ tumor-specific T cells were expanded in vitro from primed spleens of mice immunized against TTRNA extracted from KR158B-luc. These T cells were adoptively transferred after 5–7 d of in vitro activation into KR158B-luc intracranial tumor-bearing C57Bl/6 mice followed by TTRNA-NPs or TTRNA-pulsed DCs. (C) C57Bl/6 mice were implanted with B16F0 melanomas (250,000 cells/mouse) in the flank and vaccinated 1 d later with weekly TTRNA-NPs × 3 (*p < 0.05; **p < 0.01, Mann–Whitney test). (D) C57Bl/6 mice were implanted with B16F0 melanomas (250,000 cells/mouse) in the flank and vaccinated 1 d later with weekly TTRNA-NPs that were pre-treated with an IFN-α-blocking antibody. (E) C57Bl/6 mice were stereotactically implanted with KR158B-luc astrocytoma cells and received a single dose of 9Gy TBI (on Day 4) followed by an i.v. injection of 5 × 10⁴ lineage negative bone marrow-derived stem cells (within 6 h of TBI) and i.v. injection of 10⁷ tumor-specific T lymphocytes (1 d post-TBI).¹⁷ This was immediately followed by vaccination of 2.5 × 10⁵ total tumor RNA-pulsed DCs or TTRNA-NPs. The second and third RNA-NP/DC vaccines were administered at weekly intervals (*p < 0.05, Gehan–Breslow–Wilcoxon test).