Establishment and Characterization of Model Antigen-Expressing Melanoma Cell Lines

Significant advances in our understanding of antitumor immunity over the last two decades have ushered in an exciting era of cancer immunotherapy. During this time, several strategies have been developed to elicit robust antitumor immune responses by CD8⁺ cytotoxic T lymphocytes. Despite the documented benefits of various approaches aimed at targeting these cells, however, there remains a substantial number of patients who either fail to respond to these regimens or who relapse after an initial response. Therefore, to gain insight into mechanisms of innate and acquired resistance to immune-based therapies for cancer, we must improve our understanding of factors that regulate the induction and maintenance of T cell responses against cancer antigens. In this regard, experimental systems that enable the study of cancer antigen-specific T cells are useful tools for investigating the activation and suppression of antitumor T lymphocytes. To this end, we describe herein a method for generating and characterizing model antigen-expressing melanoma cell lines, and we specifically validate this method using two variants of B16 murine melanoma that we engineered to express the OVA₂₅₇ epitope of chicken ovalbumin, a model neoantigen against which both natural and T cell receptor (TCR) transgenic OT-I CD8⁺ T cell responses can be monitored.