Figure 6. Plasmid treated mouse B cells, and not dendritic cells, are able to prime an anti-tumor response and elicit tumor infiltration of CD8 T cells in vivo.

a. B cells and DCs from HLA-A2 expressing mice were obtained as above. B cells were treated with pTVG-SSX2, and DCs were treated with either the pTVG-SSX2 plasmid or the p41/p103 peptides along with 1000U/mL GM-CSF. Cells were cultured for 18h and adoptively transferred into the ear pinna of HHDII-DR1 mice previously inoculated with a syngeneic sarcoma cell line overexpressing SSX2 (n = 5-6/group). Tumor size was monitored over time per group. b. Representative immunohistochemistry staining for CD8a in the tumor sections from the different groups (left). Tumors were enzymatically digested to obtain single cell suspensions and stained for infiltration of immune cells. The graph on the right represents the CD8 T cell /total live cell ratio of each animal in each treatment group. For all panels, * denotes a p-value < 0.05, two-sided t-test. Data are representative of at least 2 independent experiments. Error bars represent mean + SEM.