Figure 5.

Cytotoxicity induced by CD8⁺ T cells of C57BL/6J mice against murine B16G3.26 melanoma cells after immunization with DNA vaccines encoding ubiquitinated melanoma-specific epitopes. Splenocytes were isolated 1 week after the third vaccination, and CD8⁺ T cells were analyzed for their lytic activity in a 4-h ⁵¹Cr-release assay at different effector-to-target cell ratios (E:T) ratios. (A) Specific lysis mediated by CD8⁺ T cells from different experimental groups of mice: pUb-H (○), pUb-M (♦), empty vector pUb-V (▵), and PBS (*). (B) Lysis mediated by CD8⁺ T cells was blocked by anti-MHC class I antibody (H-2K^b/D^b) after immunization with the pUb-M (♦) and pUb-H (○) DNA vaccines. Nonspecific syngeneic prostate cancer target cells (TRAMP-C1) were not lysed by pUb-M-specific CD8⁺ T cells (▿).