Methods to Improve Adoptive T-Cell Therapy for Melanoma: IFN-γ Enhances Anticancer Responses of Cell Products for Infusion

Further development of adoptive T-cell therapy (ACT) with autologous tumor-infiltrating lymphocytes (TILs) has the potential to markedly change the long-term prognosis of patients with metastatic melanoma, and modifications of the original protocol that can improve its clinical efficacy are highly desirable. In this study, we demonstrated that a high in vitro tumor reactivity of infusion products was associated with clinical responses upon adoptive transfer. In addition, we systematically characterized the responses of a series of TIL products to relevant autologous short term cultured melanoma cell lines from 12 patients. We provide evidence that antitumor reactivity of both CD8(+) and CD4(+) T cells could be enhanced in most TIL products by autologous melanoma sensitization by pretreatment with low-dose IFN-gamma. IFN-gamma selectively enhanced responses to tumor-associated antigens other than melanoma differentiation antigens. In addition, IFN-gamma treatment was invariably associated with restored/increased cancer immunogenicity as demonstrated by upregulation of major histocompatibility complex molecules. These findings suggest a potential synergism between IFN-gamma and ACT, and have important implications for clinical development of combination strategies for the treatment of metastatic melanoma. Journal of Investigative Dermatology (2013) 133, 545-552; doi:10.1038/jid.2012.336; published online 27 September 2012