Effects of recombinant human interleukin-3 on CD34-enriched normal hematopoietic progenitors and on myeloblastic leukemia cells

Abstract

Induction of proliferation and differentiation in response to recombinant human interleukin-3 (hIL-3) was studied in liquid and semisolid cultures of umbilical cord blood and bone marrow cells that were fractionated by “panning” with anti-My10 antibody according to expression of CD34 antigen. Cells from enriched fractions (70% to 90% CD34+) were found to proliferate strongly in response to hIL-3. Phenotypic analysis and morphologic characterization of the proliferating cells demonstrated a rapid decrease in CD34+ cells and an exponential increase in the number of cells belonging to the neutrophilic, eosinophilic, monocyte/macrophage, and thrombocytic lineages. When combined with recombinant human erythropoietin, burst colonies and cells expressing glycophorin-A were detected, thereby demonstrating the effects of hIL-3 on erythroid progenitors. Further, the development of mixed-erythroid colonies indicated that multipotential cells within CD34-enriched fractions responded to hIL-3. In addition, we examined the effect of hIL-3 on the proliferation of primary acute myeloblastic leukemia cells in liquid culture. We found that hIL-3 was able to induce cell proliferation in a proportion of the cases tested. Heterogeneity of the responses to hIL-3 was in part related to French-American-British classification but could not be correlated with CD34 antigen expression by the leukemic cells. These results indicate that, although the effects of hIL-3 on proliferation and differentiation of cells obtained from normal hematopoietic specimens were primarily borne by CD34+ cells, expression of the CD34 molecule per se is an insufficient condition to determine a growth response to this lymphokine.

Interleukin‐4 and RANTES expression in maturing eosinophils derived from human cord blood CD34+ progenitors

“…These cells are well characterized and relatively accessible in large numbers compared with bone marrow‐derived stem cells. Although cord blood‐derived CD34 + stem cells are phenotypically distinct from those of the bone marrow, 19 they are enriched in progenitors and exhibit the capacity to differentiate into eosinophilic cells following appropriate stimulation (IL‐3 and IL‐5) 11,13 . 14,20 Thus, cord blood‐derived CD34 + cells provide an improved system over the use of cord blood mononuclear cells for the investigation of cytokine expression in maturing eosinophils.…”

“…In particular, CD34 + cells are enriched in these preparations, which allows a more precise analysis of a well‐defined population of cells containing progenitors that can be induced to differentiate into eosinophilic cells. 11–14 We investigated gene expression of IL‐4 and RANTES, and analysed their translated products by reverse transcription–polymerase chain reaction (RT–PCR) and immunofluorescence, over 28 days of incubation in semisolid media. Our findings contribute to the elucidation of mechanisms associated with early events of cytokine regulation and storage during eosinophil maturation, with the potential to contribute to inflammatory reactions in local tissue sites.…”

IL‐3 in the Clinic

“…In preclinical [11] and clinical trials (see below), the most prominent and consistent effect of IL‐3 in vivo is a significant increase in the absolute neutrophil count (ANC). In vitro IL‐3, in combination with other cytokines such as stem‐cell factor, IL‐6, IL‐1, IL‐11, G‐CSF, GM‐CSF, erythropoietin (EPO), or thrombopoietin (TPO) induces the proliferation of colony‐forming units granulocyte‐macrophage (CFU‐GM), CFU‐Eo, CFU‐Baso, burst‐forming units‐erythroid (BFU‐E), colony‐forming units‐megakaryocyte (CFU‐MK) and colony‐forming units‐granulocyte/erythroid/macrophage/megakaryocyte (CFU‐GEMM) in semisolid medium, and it stimulates the proliferation of purified CD34 + cells in suspension culture [12‐16]. Therefore IL‐3 is included in almost all protocols to culture hematopoietic stem and early progenitor cells.…”

Comparative Effects of Insulin‐Like Growth Factor II (IGF‐II) and IGF‐II Mutants Specific for IGF‐II/CIM6‐P or IGF‐I Receptors on in Vitro Hematopoiesis

“…IGF‐II also promoted an increase in the number of CFU‐GM in interleukin 3 (IL‐3) supplemented liquid cultures of peripheral blood cells [23]. In liquid cultures, IL‐3 has been shown to stimulate the proliferation and progressive differentiation of hematopoietic progenitor cells [24–, 27]. Liquid cultures of bone marrow cells provide a model to investigate the early effects of IGF‐II on the proliferation and differentiation of hematopoietic progenitor cells and the possible role of the IGF‐I and IGF‐II/CIM6‐P receptors in mediating those responses.…”