Abstracts (complete list) - Wissenschaft Online

Sebastian Kreiter, Mustafa Diken, Abderraouf Selmi, Abdo Konur, Michael Koslowski,
Christoph Huber, Özlem Türeci, Ugur Sahin
Intranodal RNA immunisation – a potent method for the
induction of immunity by selective transfection of DC
We propose the usage of naked IVT-RNA given as intranodal (i.n.) injection as a new
vaccination method. We could show by FACS analysis after i.n. injection of eGFP RNA
into inguinal lymph nodes (LN) of BALB/c mice that DCs were transfected. Histological
analysis of RNA uptake (Cy5-RNA) in LN showed a positive signal for CD11b+ DCs in
the paracortical zone with sparing of B-cell follicles. By FACS analysis of similar treated
LN we could show that a RNA signal was predominatly measurable in CD11c/CD11b+
myeloid DCs. Using in vitro and in vivo test systems we proved that human and mouse
DCs have a high capacity for uptake of RNA in comparison to other cell populations. To
assess the translational efficacy we used the firefly luciferase system and in vivo
luminescense. After i.n., i.d. or s.c. RNA injection we measured time kinetics. The
results showed superior translational efficacy (factor 10-20) for i.n. application in
comparison with other application modalities
Using Influenza-HA specific CD4+ and CD8+ T-cells for adoptive transfer experiments
we tested the ability of i.n. RNA vaccination to expand T-cells. Strong i.n. expansion
followed by systemic distribution of T-cells was detected. They showed full effector
functions as shown by IFNγ secretion and cytotoxicity. Priming in naïve mice was tested
after i.n. immunisations with SIINFEKL RNA resulting in up to 29 % antigen-specific CD8
+ T-cells. Furthermore we showed T-cell priming against Influenza-HA, hCMV pp65 and
gp70. We could show superior T-cell expansion with i.n. RNA in comparison to i.d. or s.
c. immunisation. In tumor protection assay using an A20 Influenza HA transfectant cell
line all mice were long time protected after 4 i.n. RNA immunisations. 60% of BALB/c
mice survived in therapeutic assay after 5 i.n. RNA immuniations.
In summary we have shown that the usage of naked IVT-RNA for intranodal
immunisation is feasible, preserves lymph node structure, confers selective transfection
of DCs, leads to expansion of antigen-specific T-cells and allows the induction of antitumor
immunity.