Culture of normal and leukemic bone marrow in interleukin-2: analysis of cell activation, cell proliferation, and cytokine production.
Transplantation of bone marrow autografts activated by culture in interleukin-2 (IL-2) followed by administration of IL-2 represents a novel approach in an attempt to combine ex vivo purging and post-transplant in vivo immunotherapy, and initial clinical results have suggested its feasibility. To further characterize the mechanism of the in vitro anti-leukemia effect, fresh bone marrow from normal donors and from patients with acute myelogenous leukemia (AML) in remission was cultured for 6 days in the absence or presence of IL-2 (1000 IU/ml). Proliferation of CD3, CD8, CD14, and CD56 cells was determined by direct immunofluorescence using flow cytometry. Predominantly T-lymphocytes (CD3+) and to a lesser extent CD56+ natural killer (NK) cells proliferate in 6-day marrow cultures in IL-2. Fresh bone marrow cells have no measurable NK activity when tested against K562 and Daudi target cell lines in a 4 h chromium-51 release assay, and it requires at least 6 days of culture in IL-2 to develop optimal cytotoxic activity. Cytokines released in the supernatants of these cultures were measured by immuno- and bioassays. Tumour necrosis factor alpha (TNF-alpha), interferon gamma (IFN-gamma), and IL-6 were found to be produced in significant amounts by marrow mononuclear cells during culture in IL-2. Even without IL-2 present, concentrations of these cytokines were increased in 6-day marrow cultures. In contrast, IL-3, IL-7, granulocyte and granulocyte-macrophage colony-stimulating factors (G-CSF and GM-CSF) were below the level of detection of the immunoassay, a result that could be confirmed for GM-CSF and IL-3 by bioassay. The data suggest that culture of marrow from normal donors as well as from patients with AML obtained in remission can generate anti-leukemia effector mechanisms which are non-crossreactive with chemo- and radiotherapy and may contribute to effective ex vivo purging of residual leukemic cells. The transplantation of such IL-2 'primed' marrow may also contribute to an in vivo graft-versus-leukemia effect.
Leukemia/Bone Marrow Transplant Program of BC, Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, Canada.
H G
HG
Klingemann
J
J
Neerunjun
U
U
Schwulera
H J
HJ
Ziltener
D001853:Bone Marrow / Q000473:pathology*; D001854:Bone Marrow Cells; D016465:Bone Marrow Purging; D002455:Cell Division; D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis*; D003602:Cytotoxicity, Immunologic; D006801:Humans; D007376:Interleukin-2 / Q000494:pharmacology*; D015979:Killer Cells, Lymphokine-Activated / Q000276:immunology; D015470:Leukemia, Myeloid, Acute / Q000473:pathology*; D008213:Lymphocyte Activation; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000473:pathology; D014407:Tumor Cells, Cultured / Q000473:pathology
D016207:Cytokines; D007376:Interleukin-2