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 (μH chains, λ5 and vpre-B surrogate L chains, and the IgMα (mb-1) and Igβ (B29) co-receptor molecules). Southern Blot analysis revealed clonal rearrangement of the μH 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..