Human Interleukin 3: Effects on Normal and Leukemic Cells

Abstract

The effects of recombinant human interleukin 3 (IL3) on normal bone marrow cells and human leukemic cells were studied. In clonal assays, IL3 supported the growth of all colony types including megakaryocytes. Erythroid colonies were formed in the presence of IL3 and erythropoietin, but not in the absence of erythropoietin. Replating experiments using blast cell colonies derived from a cell population enriched for progenitor cells by fluorescence-activated cell sorting with the monoclonal antibody 3C5, showed that IL3 supported the continued replating of colonies. The clonal proliferation of human bone marrow cells in response to IL3 was inhibited by tumor necrosis factor and by lymphotoxin, but not by interferon-gamma. In suspension cultures, IL3 supported the proliferation of mast cells. Human IL3 had no effect on the growth responses, morphology, cytochemistry, or clonogenicity of the human leukemic cell lines HL60, U-937, KG1a, and HEL. Transcripts for IL3 mRNA were not detectable in these cells, nor in the K562 cell line, implying that autocrine secretion of IL3 was not the mechanism by which these leukemias were maintained. Although cells derived from the bone marrow or peripheral blood of twenty patients with myeloproliferative disorders, myelodysplastic syndromes or acute myeloid leukemia frequently showed proliferative responses to IL3, mRNA transcripts for IL3 were not detected in these cells.

Granulocytes: effector cells or immunomodulators in the immune response to helminth infection?

“…Indeed the T‐cell dependency of some mast cell populations is demonstrated by the absence of intraepithelial intestinal MMC from humans and mice that have T‐cell deficiencies. IL‐3, IL‐4, IL‐9 and IL‐10 are all Th2 cell cytokines that are known to influence mast cell development and phenotype (99,100). The necessity for these cytokines in mast cell development has largely been analysed using mouse models of helminth infection (see below).…”

Tiazofurin-induced autosecretion of IL-6 and hemoglobin production in K562 human leukemia cells

“…K562 cells are able to produce and secrete IL-6 in untreated cultures, making these cells an excellent model to study this parameter. On the other hand, it is noteworthy that transcripts of IL-3 mRNA were not detected in K562 cells, along with no autocrine secretion of IL-3 [10]. Therefore, it was not necessary to evaluate increasing levels of endogenous IL-3.…”

In-cell PCR from mRNA: amplifying and linking the rearranged immunoglobulin heavy and light chain V-genes within single cells

“…Monoclonal antibodies have provided reagents for the identification of marker proteins (and lipids and carbohydrates) expressed within cells (1), on the surface of cells (2) or secreted from cells (3). These reagents have had diverse uses, ranging from the localisation of cells in histological sections (1) to the use of fluorescence activated cell sorting (FACS) of populations of cells (4). However given the nucleotide sequence encoding a desired marker, we could in principle use the mRNA species as a marker for a cell.…”