Use of Leukemic Dendritic Cells for the Generation of Antileukemic Cellular Cytotoxicity Against Philadelphia Chromosome-Positive Chronic Myelogenous Leukemia

Abstract

The success of adoptive immunotherapy for the treatment of leukemia depends on the generation of T cells that can specifically react with malignant cells. Dendritic cells (DCs) are important antigen-presenting cells in the development of antileukemic T-cell responses. In this study, we generated DCs from peripheral blood cells of patients with chronic myelogenous leukemia (CML). CML cells incubated concurrently with granulocyte-macrophage colony-stimulating factor, interleukin-4, and tumor necrosis factor-α in vitro developed morphologic and phenotypic characteristics of DCs. Fluorescence in situ hybridization showed the presence of t(9; 22) in the nuclei of these cells, indicating that they were leukemic in origin. These cells were potent stimulators of lymphocyte proliferation in specific in vitro assays for DC function. Autologous T cells stimulated with in vitro-generated, leukemic DCs displayed vigorous cytotoxic activity against CML cells but low reactivity to major histocompatability complex-matched normal bone marrow cells. Cytotoxic activity against CML targets was fourfold to sixfold higher using DC-stimulated autologous T cells than with autologous T cells expanded by culture with interleukin-2 alone. DC-stimulated T cells also inhibited growth of CML clonogenic precursors in colony-forming assays in vitro. These results suggest that cytokine-driven in vitro differentiation of CML cells results in generation of DCs with potent T-cell stimulatory function. In vitro-generated DCs can be effectively used as antigen-presenting cells for the ex vivo expansion of antileukemic T cells.

Analysis of a Chronic Myelogenous Leukemia Patient Vaccinated with Leukemic Dendritic Cells Following Autologous Peripheral Blood Stem Cell Transplantation

“…28) In agreement with the present findings, the DCs generated from the CML progenitors have been shown to carry t(9;22), which suggests they are leukemic in origin. 13,29) In addition, the DR + CD86 + phenotype and the morphology of these mature leukemic DCs are similar to those of typical mature DCs. 13) In this in vitro study, we showed that leukemic DCs can take up exogenous particles, such as latex beads, and KLH protein.…”

“…13,29) In addition, the DR + CD86 + phenotype and the morphology of these mature leukemic DCs are similar to those of typical mature DCs. 13) In this in vitro study, we showed that leukemic DCs can take up exogenous particles, such as latex beads, and KLH protein. They can also function as potent accessory cells in the proliferation of KLH antigen-specific CD4 + T cells, as well as in stimulating an allo-T cell response.…”

“…26) Our finding, that leukemic DCs can generate leukemia-specific memory CD4 + T cells from naive T cells, means that antigen presentation by mature leukemic DCs may sustain the expression of leukemic antigens initially presented on the surface of the CML cells. 13,30) A T cell line activated by leukemic DCs in vitro showed high production of IFN-γ and specific cytotoxicity against the patient's BMMNCs and BLCLs, which express bcr-abl fusion mRNA, but not against those from a HLAmatched healthy subject, suggesting that injected leukemic DCs had anti-leukemic effects in this patient. These findings indicate that leukemic DCs apparently display an adjuvant effect in antitumor immunity.…”

“…11) In the present study, we generated a large number of leukemic DCs, i.e., DCs of leukemic origin, by using granulocyte colony-stimulating factor (G-CSF) to mobilize PBSC, 12) and we investigated whether these cells effectively present leukemia antigens to T lymphocytes and activate antileukemic CTL without the addition of exogenous antigens. 13) We also characterized the efficacy of this novel procedure for treating patients with CML.…”

Modulation of antitumor immune responses by hematopoietic cytokines

“…70 Myeloid progenitors obtained from patients with AML differentiated to enhanced antigenpresenting cells when treated in vitro with GM-CSF, TNF, IL-4, CD40 ligand, Flt3, or SCF. 71 Likewise, others have reported similar results after GM-CSF, TNF, and IL-4 culture of cells obtained from patients with AML and CML; 72,73 and Coleman et al reported the restoration of costimulatory molecules on GM-CSF and IL-4-incubated T-cells obtained from patients with CML. 74 In a series of interrelated trials reported by Bedi et al and Jones et al, CML progenitor cells were eliminated preferentially from culture through terminal differentiation in the presence of hematopoietic growth factors.…”