Heat production as a quantitative parameter for cell differentiation and cell function.

: Heat production was measured in relation to cell differentiation and phagocytie function using cells of human monocyte-histiocyte cell line U937. U937 cells differentiated monocytic phagocytes when cultured with lymphokine. Heat production increased as result of differentiation and phagocytosis. An important finding was that the heat increase in differentiated cells and during phagocytosis was directly proportional to the concentration of lymphokine. This strongly suggested that heat production is a quantitative parameter not only for cell differentiation but also for phagocytic function. The measurement of heat produced by mammalian cells can therefore be used to quantitate the differentiation and function of cells.