FIGURE 2.

Characterization of IL-15 and IL-15RA expression on transduced TC-1 cells and tumor growth in C57BL/6 mice. A, Schematic diagram of the IL-15, IL-15RA, and the chimeric IL-15/IL-15RA constructs. The IL-15 construct encodes the IL2SP linked to IL-15 followed by IRES and GFP. The IL-15RA construct encodes IL-15RA followed by IRES and GFP. The IL-15/IL-15RA construct encodes the IL2SP linked to IL-15 attached to IL-15RA via a 26-aa poly-proline linker followed by IRES and GFP. B, Flow cytometry data demonstrating IL-15 and IL-15RA expression on TC-1 cells transduced with IL-15, IL-15RA, or IL-15/IL-15RA. GFP⁺ cells were sorted before staining for IL-15 and IL-15RA. C, C57BL/6 mice (n = 5/group) were injected with 5 × 10⁴ TC-1 tumor cells/mouse transduced with IL-15, IL-15RA, or IL-15/IL-15RA s.c. into the left flank. Eighteen days later, tumors were isolated and weighed. Bar graph represents the average tumor mass on day 18 after injection of transduced TC-1 cells. p-values were determined by one-sided Student’s t test. The data shown here are from one representative experiment of two performed.