CD64, the high affinity receptor for IgG (FcgammaRI) is expressed on acute myeloid leukemia blast cells and has recently been described as a specific target for immunotherapy. To generate a recombinant immunotoxin, the anti-CD64 single chain fragment (scFv) m22 was cloned into the bacterial expression vector pBM1.1 and fused to a deletion mutant of Pseudomonas exotoxin A (ETA'). Genetically mod...

BACKGROUND Deoxycytidine kinase (dCK) is responsible for the activation of several clinically important deoxynucleoside analogues used for the treatment of haematological and solid malignancies. AIM To measure dCK expression in tumour cells from different origins. METHOD A rabbit antihuman dCK antibody was used for the immunocytochemical detection of dCK expression in three leukaemic cell l...

Adhesion of leukocytes to endothelial cells in inflammation processes leads to changes of endothelial cell-substrate adhesiveness, and understanding of such changes will provide us with important information of inflammation processes. In this study, we used a noninvasive biosensor system referred to as real-time cell electronic sensor (RT-CES) system to monitor the changes in endothelial cell-s...

Incubation of the human monoblastoid tumor cell line U937 with 5 x 10(-9) M 12-O-tetradecanoylphorbol-13-acetate (TPA) for 3 days was associated with marked morphological and functional changes including adherence of the cells and cessation of proliferation. While growth arrest and the viability of the cells were not influenced, the TPA-induced adherence of U937 cells could be totally blocked b...

TNF-alpha transduces signals of survival or death via its two receptors, R1/p55/p60 and RII/p80/p75. The role of caspases as effectors of cell death is universally accepted, although caspase inhibitors may potentiate TNF cytotoxicity in some instances. In conditions when macromolecular synthesis is blocked, caspases are part of the machinery that executes TNF-triggered apoptotic death in U937, ...

The mechanisms that regulate the transcription of the tumour suppressor genes p53 and IRF-1 are poorly understood. We have characterized a 68-kDa transcription factor, GAAP-1 (gatekeeper of apoptosis activating proteins), encoded by an alternative splice product of the PRDII-BF1 gene, that recognizes a novel regulatory element within the p53 and IRF-1 promoters. Transfection of U937 cells with ...

Calpain is a calcium-dependent cysteine protease that is implicated in calcium-dependent cell death, and calpain inhibitors are generally considered as inhibitors of apoptosis. To the contrary, in the present study, we found that calpain inhibitor II (CPI-2) triggers rapid apoptosis in acute lymphoblastic leukemia (ALL) and non-Hodgkin's lymphoma (NHL) cells. All target cell lines were killed b...

U937 cells, an established monoblast or early monocyte cell line, were assessed as a model in vitro for the regulation of cell growth at the single cell level. Colony formation by 500 U937 cells, preinduced to a state of responsiveness to lactoferrin (LF) by incubation with human y Interferon was suppressed by LF. LF-suppressed colony formation was restored by partially purified growth activity...