Martin M, Strasser A, Baumgarth N, Cicuttini F M, Welch K, Salvaris E, Boyd A W
Lions Laboratory, Royal Melbourne Hospital, Victoria, Australia.
J Immunol. 1993 May 15;150(10):4395-406.
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.
悬浮前粒细胞/巨噬细胞（SPGM1）细胞系源自一种可移植的小鼠前粒细胞/前巨噬细胞瘤。令人惊讶的是，SPGM1细胞表达典型的CD5前B细胞表型，对Ly-1（CD5）、PB76、B220（CD45RA）以及前B免疫球蛋白受体复合物（μ重链、λ5和vpre-B替代轻链，以及IgMα（mb-1）和Igβ（B29）共受体分子）呈阳性。Southern印迹分析显示μ重链基因座的克隆重排和种系轻链基因座。在小鼠白细胞介素-3存在的情况下，SPGM1在软琼脂中形成原始细胞、巨噬细胞以及偶尔的粒细胞集落。白细胞介素-3还在悬浮培养中诱导SPGM1细胞向巨噬细胞分化。通过Northern印迹分析在24小时时可检测到最早的变化。白细胞介素-3处理增加了Mac1 mRNA，诱导了c-fms mRNA，并下调了μ、λ5、vpre-B和mb-1的mRNA。2至4天后，细胞变大，强烈贴壁，表达巨噬细胞标志物Mac1和F4/80，失去了μ重链和PB76表面表达，并易于吞噬乳胶珠。因此，SPGM1具有CD5 +前B细胞系的所有特征。然而，白细胞介素-3主要诱导SPGM1将其分化程序从前B细胞转变为巨噬细胞。几乎整个群体的这种可诱导的快速转变为细胞命运决定所涉及机制的分子分析提供了一个独特的模型。
