Co-expression of IL-15 enhances anti-neuroblastoma effectivity of a tyrosine hydroxylase-directed DNA vaccination in mice - Fig 3

Characterization of the murine neuroblastoma cells NXS2-HGW (A-B) and evaluation of DNA vaccine-induced gene delivery in vivo (C-D). RT-PCR analysis of mRNA expression (TH, MYCN and GAPDH) by the tumor cells NXS2-HGW that were used for evaluation of anti-NB effects of the generated vaccine in vivo (A). NTC: no template control. For flow cytometry analysis of GD2 expression (B), NXS2-HGW cells were stained with Alexa 647 labeled anti-GD2 Ab (filled black curve) or respective isotype control (open gray curve). C-E: Mice (n = 3) were subjected to 4 oral vaccinations at seven day intervals with 5×107 salmonella typhimurium (strain SL7207) carrying a plasmid encoding eGFP. For isolation of Peyer’s Patches, mice were sacrificed 72 h after last immunization. Cryo-sections (6 μm) were fixed followed by H&E staining (C; 40× and 100× magnification) or staining of the nucleus with DAPI for fluorescence microscopy (D; eGFP in green, DAPI in blue, 200× magnification). Arrows indicate area of green fluorescence representing plasmid incorporation. Peyer’s patches of mice inoculated with empty vector-bearing SL7202 served as negative control (E).