Figure 2. Combining OX40L-FP with MVA-Twist-TRICOM expands CD4⁺ and CD8⁺ T-cell populations in non‒tumor-bearing mice, while enhancing Twist-specific immune responses.

A., Frequency of OX40⁺ T-cells within the activated CD3⁺CD4⁺Foxp3^-CD44⁺ population of the DLN 3, 5, and 7 days after vaccination. B., Absolute numbers of CD4⁺Foxp3^- and CD8⁺ T-cells in the spleens (n = 5) on day 21 post tumor transplant. Mice were given MVA-Twist-TRICOM on days 0, 7, and 14, and OX40L-FP on days 3, 6, 10, and 13 to maximize OX40 ligation on activated CD4⁺Foxp3^- T-cells. C./D., Representative contour plots (denoting frequencies) and absolute numbers of CD4⁺ and CD8⁺ Tem (CD44⁺CD62L^-) and Tcm (CD44⁺CD62L^-) populations. E., Twist-specific CD4⁺ T-cell proliferation assay. Pooled CD4⁺ T-cells, isolated from spleens on day 28 post tumor transplant, were stimulated with MHC-II–restricted Twist peptide in the presence of irradiated APCs. H³-thymidine uptake was measured 4 days later. F. Absolute numbers of Twist-tetramer⁺ CD8⁺ T-cells in the spleens and DLNs.