Mimotopes for tumor-specific T lymphocytes in human cancer determined with combinatorial peptide libraries

Mimotopes of a tumor-associated T cell epitope were determined using randomized and combinatorial peptide libraries and a CD8(+) T cell clone specific for the cutaneous T cell lymphoma cell line MyLa. Antigen recognition by this clone was found to be HLA-B8 restricted. More than 80 % of HLA-matched patients with cutaneous T cell lymphoma had mimotope-specific CD8(+) T cells in their peripheral blood. Mimotope-specific T cells isolated and expanded from a patient lysed MyLa cells in in vitro assays thus demonstrating their cytolytic capacity and tumor specificity. Mimotope vaccination of a patient without detectable mimotope-specific T cells induced frequencies of these cells of up to 1.82 % of the peripheral blood CD8(+) T cells.