Characterization of autologous tumor-specific T-helper 2 cells in tumor-infiltrating lymphocytes from a patient with metastatic melanoma

Human autologous tumor-specific T-helper 2 (Th2) cells were investigated in melanoma tumor-infiltrating lymphocytes (TILs). Both a CD4⁺ T-cell line and its 5 potential T-cell clones established from TILs of a patient with metastatic melanoma produced significant levels of IL-4, IL-6, IL-10 and granulocyte-macrophage colony-stimulating factor (GM-CSF) in response to autologous, but not any of 12 allogeneic, melanoma cell lines. They also produced IL-3 and IL-8 but not IL-2, IFN-γ, TNF-α or TNF-β in response to autologous tumor cells. Furthermore, they showed autologous melanoma-specific cytotoxicity only in an 18-hr ⁵¹Cr-release assay. Specific IL-4, IL-6 or IL-10 production by the CD4⁺ M73 T-cell line and its clone was inhibited by anti-class 11 DR (but not anti-class 1) MAb, whereas their specific cytotoxicity was inhibited by anti-class 1 (but not anti-class 11) MAb. Anti-CD3 and -CD4 MAb (but not anti-CD8) abrogated both IL-4, IL6 and IL-10 production and cytotoxicity, while anti-IL-4 antibody did not inhibit cytotoxicity. CD4⁺ potential T-cell clones, but not CD8⁺ clones, that were established from freshly isolated TILs without in vitro sensitization by autologous tumor cells also produced IL-4, IL-6 and IL-10 but not IFN-γ or tumor necrosis factor (TNF)α in an autologous tumor-specific fashion. These Th2 cells were neither reactive to EBV-B cells nor suppressive against CD8⁺ T-cell clones. PMA and PHA stimulated these potential T-cell clones, regardless of their specific lymphokine production, to produce IL-3, IL-4, IL-6, IL-8, IL-10, GM-CSF, TNFα and IFN-γ. Our results demonstrate the presence of autologous tumor-specific Th2 cells at the melanoma sites.