GENERATION OF MELAN-A MART-1-SPECIFIC CD8(+) CYTOTOXIC T-LYMPHOCYTES FROM HUMAN NAIVE PRECURSORS - HELPER EFFECT REQUIREMENT FOR EFFICIENT PRIMARY CYTOTOXIC T-LYMPHOCYTE INDUCTION IN-VITRO/

This study investigates the generation of primary melanoma cell-specif ic cytotoxic T lymphocytes (CTLs) in vitro. Induction of peptide-speci fic CTLs from unfractionated naive peripheral blood mononuclear cells from HLA-AZ healthy donors was assessed using 2 recently described 9-m er epitopes from the melanoma tumor antigen Melan-A/MART-1. The need f or help from CD4(+) T lymphocytes for the longlasting induction of CTL s and the capacity of the peptide-induced CTL lines to recognize many melanoma cells were evaluated. CTL lines were obtained reproducibly wh en CD4(+) T-lymphocyte help was provided during the primary stimulatio n either in an autologous way, in the case of tetanus toroid antigen ( TT) responder donors, or with allogeneic TT-activated T-helper cells, separated by an insert well, in the case of tetanus toroid non-respond er donors. We also investigated helper T-cell-derived factors that are produced by TT-activated lymphocytes. Our results strongly suggest th at a complex network of cytokines like interleukin-2 (IL-2), interfero n-gamma, IL-6 and IL-1 exerts stimulatory effects for the initiation p rocess of CTLs. In contrast, cytokine-like IL-4 might inhibit generati on of cytolytic activity if provided by TT-activated T cells at early stages of induction. Our approach can be used to generate CTLs of a de sired specificity for clinical use in adoptive immunotherapy protocols . (C) 1997 Wiley-Liss, Inc.