Differentiation in vitro of a leukemia virus-induced B-cell lymphoma into macrophages.

Abstract

Cells of the hemopoietic system arise by proliferation and differentiation of progenitor cells. This process begins with multipotential stem ceUls which can self-renew and also undergo progressive differentiation to progenitor cells committed to particular lineages, ultimately yielding mature blood cells (D. Metcalf and M. A. S. Moore, Haematopoietic Cells, 1971). Early commitment of lymphoid progenitors is generally believed to separate the lymphoid lineage from the myeloid and erythroid lineages, whose progenitors are separated late in differentiation (Metcalf and Moore, 1971). We recently developed a derivative of Moloney murine leukemia virus (M-MuLV) in which the enhancer sequences from simian virus 40 were substituted into the M-MuLV long terminal repeat. This recombinant virus (AMo+SV M-MuLV) induces pre-B and B lymphoid leukemia with long latency after inoculation of 2-day-old NIH Swiss mice (R. Hanecak, P. K. Pattengale, and H. Fan, J. Virol. 62:2427Virol. 62: -2436Virol. 62: , 1988 (Fig. 1B) demonstrated lymphoblastic lymphoma with small-to-intermediate lymphoid cells with monomorphic nuclei, scant cytoplasm, and primitive, dispersed nuclear chromatin. Positive immunoperoxidase staining of tumor tissue sections with the monoclonal antibody RA3-6B2 specific for the B220 antigen (a B-celllineage-specific marker [14]) indicated that the lymphoid tumor was B cell derived (data not shown). In addition, molecular analyses of high-molecular-weight DNA prepared from the tumor showed both immunoglobulin heavy-and light-chain gene rearrangements (8).The AMo+SV M-MuLV-induced lymphoblastic lymphoma described above was established in culture by finely mincing the leukemic cervical lymph node and plating the tissue in Dulbecco modified Eagle medium supplemented with 15% fetal calf serum, 4.0 mM L-glutamine, nonessential amino acids (GIBCO), and 5 x 10' M 2-mercaptoethanol. induced lymphoma (Fig. 1B), the 85-2M cells exhibited a morphology typical of macrophages on cytocentrifuge preparations (Fig. 1A). The cells demonstrated conspicuous vacuolated cytoplasm with eccentric nuclei and were irregular in shape.The 85-2M cells were also tested for the presence of surface antigens found associated with lymphoid cells or myeloid cells. 85-2M cell suspensions (1.5 x 106 cells) were incubated separately at 4°C with antibodies directed against Thyl.2 or B220 (T-and B-cell surface markers, respectively [5,12]) and also with antibodies against Mac-i or Mac-2, surface markers characteristic of myeloid cells and not generally found associated with lymphoid cells (9, 16). Monoclonal antibodies directed against B220, Mac-i, and Mac-2 antigens were not directly conjugated to fluorescein isothiocyanate and therefore were indirectly labeled by a second reaction with goat anti-rat fluorescein isothiocyanate-conjugated second antibody. Unstained 85-2M cells and 85-2M cells incubated with the second antibody alone were used to control for nonspecific fluorescence. The results of flow cytometry are shown in Fig. 2. The 85-2M cells, whil...

Stage transitions in B-lymphocyte differentiation correlate with limited variations in nuclear proteins.

“…Moreover, this model throws some light on the observed conversion from pre-B cell to myeloid cell (21,22 …”

“…Further evidence for the proximity between the two lineages has come from the in vitro conversion of pre-B leukemia cells into macrophages (22). The existence of a group of nuclear proteins that are highly expressed in both macrophages and pre-B cell lines and whose expression decreases during B-cell differentiation (class C) might be interpreted as corresponding to proteins expressed at a basal level in precursor cells and linked to some specialized macrophage function, thus explaining their induction in macrophages and their repression in plasmocytes.…”

Determinants for transformation induced by the Axl receptor tyrosine kinase

“…In the error-prone retroviral system used here, transformation by two of three viral strains (SV8 and 1B1) was primarily caused by dramatic overexpression of Axl rather than through activating mutations, since both viral sublines transmit the intact axl sequence. Activating promoter mutations of the MoMLV-LTR can account for upregulated gene expression and have also been documented to change the host expression speci®city of the retrovirus (Hanecak et al, 1991). The possibility that viral infection induced cellular transformation by insertional mutagenesis is unlikely since the acutely transforming nature of the viral strain was carried with each successive viral passage.…”

Myeloid Antigen, CD13, CD14, and/or CD33 Expression Is Restricted to Certain Lymphoid Neoplasms

“…30 This anomalous expression of MyAg on differentiated B-cell leukemia and lymphoma suggest that the pathways of B-lymphoid and myeloid differentiation may be closer than previously appreciated. In fact, some investigators have reported that B-cells can differentiate into macrophages, 31 and that monocytoid cells can generate into plasma cells. 32 In addition, Epstein and colleagues 33 speculated that a multipotent progenitor cell was involved in MM on the basis of the presence of MM cells expressing multilineage markers.…”