Morphologic variations in human leukemic lymphoblasts (CCRF-CEM cells) after long-term culture and exposure to chemotherapeutic agents:A study with the electron microscope

Abstract

The morphology of human leukemic lymphoblasts (CCRF-CEM cells) maintained in continuous log-phase suspension cultures for more than one year has been studied at regular intervals with the electron microscope. During this time, minor changes in morphology have been observed, the most striking change being the appearance and persistence of very dense granules in the pars amorpha of the nuclcoli. The effects of a series of inhibitory agents have been studied but no virus particles have been observed in these or untreated CCRF-CEM cells, although the wrapping of dense cell fragments by remnants of nuclear membrane under a variety of conditions leading to cell destruction was suggested as the mechanism of formation of the “virus-mimickers” observed in these studies. Deliberate search by electron microscope and cultural studies has failed to reveal evidence of the presence of Mycoplasma in the CCRF-CEM cells or cell cultures.