Thermodependence of human lymphocyte kinetics in vitro

Lymphocytes from 35 healthy children were grown in cultures supplied with 5-bromodeoxyuridine at different temperatures (33-40 degrees C) for 48-120 h. The mitotic index and the distribution of the percentages of cells having passed one, two, and three or more DNA replications were quantified for each experimental condition. A replication index was calculated, whose dependence on temperature was depicted in the form of two Arrhenius plots (after 72 and 96 h of culture). Results showed the thermodependence of the lymphocyte kinetics. A break point at 36.1 degrees C was found in the two Arrhenius plots. The energies of activation (kJ/mol) under the break point, 197.2, and over the break point, 100.1 (72 h) and 43.1 (96 h), were calculated.