Figure 8

The effect of treatment with sTGF-βR on established E7-specific CD8⁺T cells that were generated by Ad.E7 administration. (A). Groups of mice were immunized with Ad.E7. Seven days post-immunization, splenocytes were isolated and subjected to flow-cytometric analysis (“Day 7 E7-specific CD8⁺ percentage”) using anti-CD8 antibody and E7 tetramer. Displayed values are mean percentages of E7-tetramer positive CD8⁺ T cells among total splenic CD8⁺ T cells. Then, at this time point of 7 days post-immunization, other groups of mice (n=3) were treated with IgG2a or sTGF-βR. At day 14 post-immunization, splenocytes from these animals were isolated and subjected to flow-cytometric analysis. The percentage of E7-specific CD8⁺ T cells from control animals treated with IgG2a on day 14 post-immunization with Ad.E7 (“Day 14 E7-specific CD8⁺, Control IgG2a”) was significantly less than the Day 7 E7-specific CD8⁺ percentage: 0.8% vs. 1.9%, respectively (* = p < 0.05). However, the percentage of E7-specific CD8⁺ T cells from animals treated with sTGF-βR on day 14 post-immunization with Ad.E7 (“Day 14 E7-specific CD8⁺, TGF-β-blockade”) was not significantly different than the Day 7 E7-specific CD8⁺ percentage (NS, p > 0.05). (B). Examples of two-color (FITC and APC) flow-cytometry dot plots in the analysis of CD8⁺ T cells isolated from the groups described in part 6A. Displayed values are percentages of CD8⁺ E7 tetramer-positive cells among total splenic CD8⁺ T cells. “Day 7 Ad.E7” = non-treated animals 7 days after immunization with Ad.E7. “Day 14 Ad.E7/Control IgG2a” = animals 14 days after immunization with Ad.E7 and 7 days after IgG2a treatment. Day 14 Ad.E7/TGF-β-blockade = animals 14 days after immunization with Ad.E7 and 7 days after sTGF-βR treatment.