NON-FASTIDIOUS, MELANOMA-SPECIFIC CD8-LYMPHOCYTES FROM CHOROIDAL MELANOMA PATIENTS( CYTOTOXIC T)

To characterize the anti-melanoma reactivity of CD8+ cytotoxic T lymph ocytes (CTL) from choroidal melanoma patients, CTL clones were isolate d from the peripheral blood of three patients after mixed lymphocyte/t umor cell culture (MLTC). Clones were derived from lymphocytes stimula ted by allogeneic (OCM-1, A24, A28) or autologous (OCM-3, A1, A30) mel anoma cells. Their reactivity against a panel of HLA-typed melanoma an d nonmelanoma cells was assessed, to determine whether a single CTL cl one could recognize and lyse a variety of allogeneic melanoma cell lin es. While proportionately more clones derived from autologous MLTC wer e melanoma-specific than allogeneic MLTC (42% versus 14%), melanoma-sp ecific CTL were recovered from both. Notably, a novel melanoma specifi city was identified. These CTL clones were termed non-fastidious becau se they were capable of lysing melanoma cells with which they had no H LA class I alleles in common. Nonetheless, lysis was mediated by the H LA class I molecule. Since lysis was specific for melanoma cells, thes e CTL appeared to recognize a shared melanoma peptide(s). Because of t heir prevalence, we propose that non-fastidious CTL are integral to hu man anti-melanoma T cell immunity. This reinforces clinical findings t hat allogeneic melanomas can substitute for autologous tumors in activ e specific immunotherapy. By circumventing the need for autologous mel anoma, it is possible to treat patients after removal of the primary c horoidal melanoma in an attempt to prevent metastasis.