Figure 1.

Intratumoral administration of dendritic cells engineered to express T-bet/TBX21 (DC.Tbet) promote the rapid infiltration of Type-1-polarized lymphocytes and dendritic cells and the development of PNAd⁺ endothelial cells (i.e., HEV). Tbet-ZsGreen Tg mice were injected sub-cutaneously with syngenic MCA205 sarcoma cells and tumors allowed to progressively grow for 7 days, at which time control DC (Control) or DC engineered with recombinant adenovirus to express murine T-bet cDNA were inoculated directly into tumors, as previously described (5). Two or 5 days after DC injection, the mice were euthanized and tumor sections evaluated by fluorescence microscopy for expression of Tbet-ZsGreen protein, CD11c (a marker of DC), B220 (a B cell marker), and PNAd (i.e., Peripheral lymph Node Addressin; a high endothelial venule (HEV) cell marker). PNAd⁺ HEV were not observed by 2 days post-treatment, but became prevalent by 5 days post-injection of DC.Tbet cells. B, T, and NK cell infiltrates into DC.Tbet [Figure 1 and (5)] exhibited a diffuse distribution pattern in day 2 and day 5 DC.Tbet-treated tumors. Type-1 polarity in infiltrating cells is denoted by nuclear expression of Tbet-ZsGreen. Data are representative of images obtained in three independent experiments performed.