Figure 1.

AAV6-Based Vaccines Induce Strong Cellular and Humoral Response against Antigen by Targeting DC In Vivo

(A) Optimization of the AAV6 capsid increases proportion of Ova_257–264-tet⁺ cells. The levels of Ova_257–264-tet⁺ cells were measured in the blood of mice by using Ova MHC class I tetramers 14 days after i.m. immunization with different AAV6-Ova constructs. (B) The activity of Ova-specific CD8⁺ T cells was estimated by IFNγ production. Splenocytes were isolated 3 weeks after immunization and re-stimulated with Ova_257–264 peptide (SIINFEKL) to analyze IFNγ production by ELISPOT assay. (C) Vaccination induces strong humoral response. Ova-specific antibodies were measured in serial dilutions of mouse plasma 3 weeks after immunization. All values were normalized to background, which was determined as values from plasma of naive mice. Data are representative of experiments repeated 3 times with similar results. OD, optical density. (D and E) AAV6/CMV-GFP administered in an i.m. injection targets DCs in vivo. Briefly, 4 days after i.m. injection, (D) DCs were isolated from drained lymph nodes by a CD11c⁺ magnetic beads kit (BioLegend) and analyzed by FACS, or (E) cells were labeled with MHC class II− APC antibodies (red channel), and the presence of GFP expression was analyzed by fluorescence microscopy. White arrows indicate DCs expressing GFP. ∗ p < 0.05. ∗∗ p < 0.01.