Cytochemical population analyses of continuous cultures of human lymphoblasts derived from acute lymphoblastic leukemia

The cytochemical characteristics of populations of human lymphoblasts (CCRF-CEM cells) in continuous log-phase suspension cultures derived from the peripheral blood buffy coat of a child with acute lymphoblastic leukemia have been determined by the use of high-resolution, rapid-scanning biophysical population analysis techniques. The pattern of distribution of the DNA content in individual cells was consistent with that of a diploid or near-diploid population in asynchronous log-phase growth, and there was no suggestion of two distinct populations, despite the presence of an extra “minute” chromosome in ca 50 per cent of the cells. The mean RNA : DNA ratio of these cells was 0.7:1.0. The distribution patterns of total nucleotide content and dry mass per cell indicated a somewhat greater degree of variability than would be expected in populations of normal cells, although this variability was not as great as that observed with populations of neoplastic cells in which individual cells were characterized by a large cytoplasmic mass. These continuously cultured human leukemic lymphoblasts resemble those examined directly in the peripheral blood buffy coat of patients with acute lymphoblastic leukemia with respect to the pattern of variability of total nucleotide and dry mass per cell.