PMEL and neoplasm: The antitumor responses occurred in the absence of adjuvant gp100 vaccine and systemic IL-2, which were not administered in this experiment but were required in the original report of tumor regression in this TCR transgenic model.19 To test if caIL-12 enhances the efficacy of antitumor T-cells, we compared tumor treatment with pmel-1 cells expressing caIL-12 to treatment with pmel-1 cells expressing green fluorescent protein.