Growth pattern of the human promyelocytic leukaemia cell line HL60

In order to characterize the growth pattern of the human promyelocytic leukaemia cell line HL60, its kinetic parameters were studied. The doubling time was calculated from serial cell counts, the duration of the various cell cycle phases from the analysis of the labelled mitoses curve, and quiescent population from continuous labelling experiments. Proliferation in culture was exponential up to a saturation density of about 3.0 x 106 cells/ml, with a doubling time of 34.0 hr. The cell cycle duration was 24.3 \ub1 4.1 hr (SD), and that of the cell cycle phases was: G1, 3.8 \ub1 2.2 hr; S, 15.1 \ub1 3 hr; and G2, 5.4 \ub1 1.2 hr. The growth fraction was 0.85, and cell loss was restricted to the quiescent cells. The HL60 cell line, with fully characterized kinetics, provides a useful tool for the in vitro study of substances which may affect human leukaemic myelopoietic proliferation