title: A novel cellular model (SPGM 1) of switching between the pre-B cell and myelomonocytic lineages.
abstract: The suspension pro granulocyte/macrophage (SPGM1) cell line was established from a transplantable mouse progranulocytic/promacrophage tumor. Surprisingly, SPGM1 cells expressed a typical CD5 pre-B cell phenotype, being positive for Ly-1 (CD5), PB76, B220 (CD45RA), and the pre-B Ig receptor complex (microH chains, lambda 5 and vpre-B surrogate L chains, and the IgM alpha (mb-1) and Ig beta (B29) co-receptor molecules). Southern Blot analysis revealed clonal rearrangement of the microH chain locus and germ-line L chain loci. SPGM1 formed blast cell-, macrophage-, and occasional granulocytic colonies in soft agar in the presence of murine IL-3. IL-3 also induced macrophage differentiation of SPGM1 cells in suspension cultures. The earliest changes were detectable at 24 h by Northern blot analysis. IL-3-treatment increased Mac1 mRNA, induced c-fms mRNA, and down-regulated mRNA for mu, lambda 5, vpre-B and mb-1. After 2 to 4 days the cells were larger, strongly adherent, expressed the macrophage markers Mac1 and F4/80, had lost microH chain and PB76 surface expression, and readily phagocytosed latex beads. Thus SPGM1 has all the characteristic features of a CD5+ pre-B cell line. However, IL-3 predominantly induced SPGM1 to switch its differentiation program from a pre-B cell to a macrophage. This inducible, rapid switch of virtually the entire population provides a unique model for the molecular analysis of mechanisms involved in cell-fate determination.
authors.affiliation: Lions Laboratory, Royal Melbourne Hospital, Victoria, Australia.
authors.forename: M
authors.initials: M
authors.lastname: Martin
authors.forename: A
authors.initials: A
authors.lastname: Strasser
authors.forename: N
authors.initials: N
authors.lastname: Baumgarth
authors.forename: F M
authors.initials: FM
authors.lastname: Cicuttini
authors.forename: K
authors.initials: K
authors.lastname: Welch
authors.forename: E
authors.initials: E
authors.lastname: Salvaris
authors.forename: A W
authors.initials: AW
authors.lastname: Boyd
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000032:analysis*; D000954:Antigens, Surface / Q000235:genetics; D001402:B-Lymphocytes / Q000166:cytology* / Q000502:physiology; D018956:CD5 Antigens; D002454:Cell Differentiation; D002460:Cell Line; D005260:Female; D015870:Gene Expression; D016236:Genes, fms; D007148:Immunoglobulin mu-Chains / Q000032:analysis / Q000235:genetics; D016130:Immunophenotyping; D066298:In Vitro Techniques; D007377:Interleukin-3 / Q000494:pharmacology; D008264:Macrophages / Q000166:cytology* / Q000502:physiology; D051379:Mice; D008809:Mice, Inbred C3H; D012333:RNA, Messenger / Q000235:genetics; D016186:Receptor, Macrophage Colony-Stimulating Factor / Q000235:genetics; D011947:Receptors, Antigen, B-Cell / Q000032:analysis / Q000235:genetics; D014407:Tumor Cells, Cultured
chemical_list: D015703:Antigens, CD; D000954:Antigens, Surface; D018956:CD5 Antigens; D007148:Immunoglobulin mu-Chains; D007377:Interleukin-3; D012333:RNA, Messenger; D011947:Receptors, Antigen, B-Cell; D016186:Receptor, Macrophage Colony-Stimulating Factor