Heat production due to intracellular killing activity

Using Saccharomyces ceravisiae, Candida albicans and Stapylococcus aureus, heat production during phagocytosis was measured in U937 cells which are capable of differentiating to monocytic phagocytes. No increase in heat production of non-differentiated U937 was observed since they were not phagocytic cells. However after differentiation to monocytic phagocytes by lymphokine, U937 cells produced a remarkable amount of heat during phagocytosis. Although Ehrlich ascites tumor cells sensitized with antibody were capable of engulfing S. aureus, no increase in heat nor in superoxide anion production during phagocytosis was detected. It was also found that no heat increase occurred in neutrophils from a patient with chronic granulomatous disease (CGD). It can thus be concluded that the heat production during phagocytosis is due to the intercellular killing process of phagocytic cells.