title: Expression of interleukin-4 receptors on early human B-lineage cells.
abstract: Interleukin-4 (IL-4) regulates multiple stages of the antigen-dependent phase of B-cell development. However, its precise role in regulating B lymphopoiesis in bone marrow is not as well defined. We examined whether surface IgM- normal and leukemic human B-cell precursors (BCP) expressed IL-4 receptors using biotinylated IL-4. Constitutive expression of IL-4 receptors was detected on both normal and leukemic BCP. A higher percentage of normal BCP (82% +/- 15%) expressed IL-4 receptors compared with leukemic BCP (44% +/- 8%). Using mean fluorescent intensity as an indicator of receptor level on the IL-4 receptor positive cells, normal (91 +/- 41) and leukemic (44 +/- 37) BCP expressed comparable numbers of receptors. IL-4 induced the expression of CD23 on 30% of the leukemic BCP cases examined. IL-4 induced CD23 on surface IgM+ fetal bone marrow lymphoid cells but not on the surface IgM- normal BCP, despite the presence of detectable receptors on the surface IgM- cells. IL-4 did not stimulate proliferation of normal BCP, nor could it enhance the effect of recombinant IL-7 or low molecular weight B-cell growth factor. However, IL-4 increased the expression of surface IgM and surface Ig kappa on in vitro differentiated pre-B cells. Our collective results identify no role for IL-4 in the proliferation of normal or leukemic BCP, but identify a role in the enhancement of surface Ig expression during pre-B to B-cell differentiation.
authors.affiliation: Department of Laboratory Medicine/Pathology, University of Minnesota Medical School, Minneapolis.
authors.forename: C L
authors.initials: CL
authors.lastname: Law
authors.forename: R J
authors.initials: RJ
authors.lastname: Armitage
authors.forename: J G
authors.initials: JG
authors.lastname: Villablanca
authors.forename: T W
authors.initials: TW
authors.lastname: LeBien
mesh_terms: D001402:B-Lymphocytes / Q000276:immunology* / Q000473:pathology; D001853:Bone Marrow / Q000276:immunology / Q000473:pathology; D002478:Cells, Cultured; D004261:DNA Replication; D005434:Flow Cytometry; D006801:Humans; D015847:Interleukin-4 / Q000378:metabolism; D007700:Kinetics; D008213:Lymphocyte Activation; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000276:immunology* / Q000473:pathology; D019948:Receptors, Interleukin-4; D011975:Receptors, Mitogen / Q000032:analysis* / Q000378:metabolism; D012016:Reference Values
chemical_list: D019948:Receptors, Interleukin-4; D011975:Receptors, Mitogen; D015847:Interleukin-4