Figure 5.

Locally activated antitumor T cells circulate systemically to eradicate systemic disease

A-C. Mice were implanted with either CT26 or 4T1 tumor cells as previously described in Figure 1 and 3 respectively and treated with either vehicle or intratumoral CpG and aOX40. Splenocytes from the indicated groups harvested on day 4 after treatment and cocultured with either media, CD3 and CD28 antibodies, A20 cells (unrelated control tumor), or homologous tumor cells for 24 hours. A. Schematic illustration of experiments. B. For 4T1, analyzed population was enriched for CD3+ cells. Intracellular IFN-γ was measured in CD8+ T cells by flow cytometry as a percentage of CD44hi (memory CD8) T cells shown in dot plots and bar graph n=3 mice/group, ns=not significant **p = 0.0018 (4T1) *p=0.044 (CT26), unpaired t test. C. Intratumoral injection of aOX40+ CpG induces production of Granzyme B and proliferation of CD8+ T cells in lungs and draining lymph nodes of treated mice by day 4 post treatment. Single cell suspensions of draining lymph nodes (dLN) and lungs were stained for Ki67 and Granzyme B, highlighted are percentages of the double positive cells. n=3 mice/group, ***p = 0.000557, *p = 0.0137 (4T1) *p=0.0489, ns=not significant (CT26), unpaired t test.