M. Wallenohman et al., ANTIBODY-INDUCED APOPTOSIS IN A HUMAN LEUKEMIA-CELL LINE IS ENERGY-DEPENDENT - THERMOCHEMICAL ANALYSIS OF CELLULAR-METABOLISM, Cancer letters, 75(2), 1993, pp. 103-109
The mouse monoclonal anti-BAL antibody induced apoptosis in a pre-B ac
ute lymphocytic leukemia cell line within 2 days of incubation, after
being crosslinked by a secondary antibody. The antibody specifically r
ecognized a 37 kDa membrane protein that was expressed on a wide spect
rum of normal and malignant cells, but induced programmed cell death i
n only very few of these cells. In this study, we have followed the in
itial kinetics of the antibody-induced cell death in the human acute l
ymphocytic leukemia cell line KM-3, by microcalorimetric measurements
in conjunction with determination of the cellular proliferation rate a
nd DNA fragmentation. An increase in metabolic activity was observed a
lready after incubating the cells for 20 min with crosslinked anti-BAL
antibody, which was several hours before significant growth inhibitio
n and DNA fragmentation were detected. These data show for the first t
ime that the initiation phase of antibody-induced apoptosis is an acti
ve, energy-dependent process and not merely an effect of receptor bloc
king.