In Vitro Induction of Myeloid Leukemia Specific CD4 and CD8 T-Cells by CD40 Ligand Activated B Cells Gene-Modified to Express Primary Granule Proteins.
Abstract The closely-related primary granule proteins are a source of multiple antigens with immunotherapeutic potential for myeloid leukemias. To further explore the possibility of generating leukemia-specific T cell responses, DNA vectors encoding the primary granule proteins proteinase 3 (PR3), human neutrophil elastase (HNE) and cathepsin-G (CathG) were transfected into autologous CD40-activated B (CD40-B) cells and used to stimulate T cell responses from peripheral blood T cells of five patients with myeloid malignancies and three ALL patients three months post-bone marrow transplantation (BMT), and one patient with CML-BC pre-transplant. T-cell responses were measured by flow-based intra-cytoplasmic IFN-g assay and cytotoxic assay. CD8 and CD4 cell response to PR3 and HNE were observed in CD8+ and CD4+ T-cells in 6/6 patients with myeloid leukemias with various degrees. T-cell response against CathG were found in both myeloid and lymphoid leukemias. We conclude that gene-transfected CD40-activated B cells are fully capable of expanding functionally-competent primary granule protein-specific CD4 and CD8 T cells, making this approach a valuable means of expanding leukemia antigen-specific T cells for adoptive immunotherapy. PGP-DNA primed T cells showed CTL activity to CML cell (case#5, post transplant) CTL activity % ( E:T ratio ) CML cell; recipient BM cell, normal BM; HLA identical DNR BM cells Effector cells Target 50:1 25:1 12.5:1 PR3-primed CML cell 63.8 54.6 30.4 normal BM 15.5 13.1 5.9 HNE-primed CML cell 43.9 38.3 32.1 normal BM 0 4.1 2.3 CathG-primed CML cell 43.1 29.1 27.5 normal BM 0 0 1.7 mock-primed CML cell 33.3 34.2 29.5 normal BM 5.5 12.9 0