Cultured human T-lymphoblastoid cell lines are more sensitive than B-cell lines to 2'-deoxyadenosine in the presence of 2'-deoxycoformycin, a potent inhibitor of adenosine deaminase. This difference is related to the greater efficiency with which T-lymphoblasts accumulate cytotoxic levels of dATP derived from the adenosine deaminase substrate 2'-deoxyadenosine (dAdo). Previous work has shown th...

Infection of the lymphoblastoid CEM cell line with herpes simplex virus (HSV) type 1 results in a persistent infection with production of infectious virus. Evidence suggests that the persistent infection was not maintained by interferon or non-interferon-soluble antiviral inhibitors. Treatment of persistently infected cells with anti-HSV serum (termed CEMACR cells) or elevated temperature (39 d...

BACKGROUND AND OBJECTIVES Drug-resistant leukemia cells may exhibit cross-resistance towards immunological effector mechanisms by alterations of apoptosis pathways. This is particularly relevant in allogeneic bone marrow transplantation for leukemia, where the graft-versus-leukemia effect acts on cells pretreated with cytostatic drugs. Here, we clarify the mechanism underlying cross-resistance ...

We have studied the potential use of immunotoxins (ITs) for therapeutic treatment of human tumors in an experimental model of human neoplasia. We tested intact ricin IT for its antitumor activity against established tumors. CEM, a human T-cell leukemia line expressing an Mr 67,000 cell surface antigen, and Daudi, a human B-cell lymphoma line which does not express the antigen, were found to be ...

Methotrexate (MTX)-resistant sublines of malignant human cells were selected in vitro by stepwise increase in drug concentration in the medium. By this procedure a subline of Burkitt's lymphoma cells (RAJI) was made 290-fold resistant (RAJI/MTX-R), T-cell leukemia cells (CCRF-CEM) were obtained 210-fold resistant (CEM/MTX-R), and 3 MTX-resistant human osteosarcoma lines were selected: TE-85/MTX...

Near diploid leukemic T-cells (LALW-2), exposed to cytotoxic drugs only as a consequence of therapy administered to the donor patient, have been maintained by serial xenograft in nude mice. In comparison with the leukemic line CCRF-CEM, using a growth inhibition assay, LALW2 cells were resistant to Vinca alkaloids and actinomycin D (relative resistance, 200-fold or more), were slightly resistan...

An autocrine (noninterleukin 2) growth factor, which we term leukemia derived growth factor (LDGF), has previously been found in the culture supernatant of the human malignant T-lymphoid cell line MOLT-4f. We now show that two other human malignant T-lymphoid cell lines, CCRF-CEM and CCRF-HSB-2 also produce such a factor. All three factors, i.e., the LDGF from MOLT-4f, CCRF-CEM, and CCRF-HSB-2 ...

Human T-lymphoblastoid cell lines RPMI 8402, MOLT-3, and CCRF-CEM were treated with interferon (IFN) to determine if the treatment would result in the disappearance of cellular terminaldeoxynucleotidyltransferase (TdT), a possible differentiation marker for T-lymphocytes. Incubation of RPMI 8402 cells in the presence of IFN preparation caused a decrease in the number of TdT-positive cells and i...

OBJECTIVE To investigate the ability of human T cell lymphotropic virus type I (HTLV-I) to infect endothelial cells and induce cytokine production by these cells. METHODS Human umbilical vein endothelial cells (HUVEC) were cocultured with HTLV-I infected T cell line (MT-2 cells) or uninfected T cell line (CEM cells). RESULTS Following coculture with MT-2 cells, endothelial cells expressed H...

Previous studies have shown that the lymphoblastic leukemia CEM cell line is resistant to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis because of a low expression of caspase-8. Bcl-2 inhibitors, BH3I-2' and HA14-1, are small cell-permeable nonpeptide compounds, are able to induce apoptosis by mediating cytochrome c release, and also lead to dissipation of th...