Cloning of Human Hematopoietic Cell Lines<xref ref-type="fn" rid="FN2">2</xref>

Abstract

The cloning characteristics of 28 human hematopoietic cell lines, 10 derived from normal persons, 12 from patients with malignant diseases, and 6 from patients with nonmalignant diseases, have been studied in a soft agar medium. All cell lines derived from the buffy coat of normal individuals and those from patients without hematopoietic malignancies had cloning efficiencies of less than 6% and developed no macroscopic colonies. Of 12 lines derived from patients with leukemia or myeloma, 4 showed intermediate cloning efficiencies of 12–36% and some macroscopic colonies, whereas the remainder had characteristics of normalcy and probably were derived from normal elements in the blood. A cell line from a patient with multiple myeloma had a cloning efficiency of more than 60%. Generally, intermediate and high cloning efficiencies were correlated with abnormal chromosome constitutions. With one exception (cell line RPMI 5157 from a patient with acute lymphocytic leukemia), low cloning efficiencies and an absence of macroscopic colonies characterized cell lines with a normal diploid chromosome pattern. Correlation between cloning efficiency and the presence or absence of the herpes-type virus (leukovirus) was not observed. Lines with high and intermediate cloning efficiencies could be subcultured from much smaller cell inocula than could lines with low cloning efficiencies; i.e., they were less dependent on population density in culture. Cloned sublines were similar to parental cell lines with respect to cloning efficiency, chromosome constitution, and production of immuneglobulins. Cloning efficiency of human hematopoietic cell lines may be regarded as an indirect indicator of the relative normality or malignancy of the cells.