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.

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)