Monocytoid leukemia cell line CTV-1: morphological, immunological and isoenzymatic characteristics

The human leukemia cell line CTV-1 was established from a case of acute monoblastic leukemia (AMoL). We analyzed the phenotypic marker profile of the CTV-1 cells in their original, untreated state and during induction of differentiation with the phorbolester 12-0-tetradecanoylphorbol 13-acetate (TPA). TPA led to morphological changes with signs of differentiation. Cell proliferation decreased in a dose-dependent fashion during exposure to TPA. In the surface marker analysis using a panel of 45 monoclonal antibodies (MoAbs) and several polyclonal antisera, CTV-1 cells were negative for markers of the T- and B-cell lineages, and were positive for several, but not all, myelomonocytic markers. Although the cells were reactive with the MoAb Leu-7 which identifies natural killer (NK) T-cells, no NK activity was detected. In the isoenzyme analysis of the four enzymes carboxylic esterase, acid phosphatase, hexosaminidase and lactate dehydrogenase (LDH) performed by isoelectric focusing on polyacrylamide gels, CTV-1 cells displayed isoenzyme profiles of immature myeloid cells. The overall marker profile of CTV-1 cells demonstrated cells of monocytoid origin arrested at a very early stage of differentiation, possibly close to the stage of precursor cells. As compared to other myelomonocytic cell lines, CTV-1 cells showed unusual morphological, immunological, functional and biochemical features and appeared to be relatively insensitive to treatment with TPA, although some alterations of the phenotype could be induced.