The metabolism of intact, normal, human lymphocytes in vitro was studied from a total of 80 subjects. Corrected for the metabolism of contaminating red blood cells, the glucose uptake, lactic acid production, and oxygen consumption were 62, 95, and 117 µmoles per 1010 lymphocytes per hour, respectively, provided the cells were incubated at concentrations greater than 40 x 106 lymphocytes per ml. At lower lymphocyte concentrations the oxygen consumption per lymphocyte rose steeply with decreasing cell concentration (crowding effect). A similar but weaker crowding effect was noted for the lactic acid production, but not for the utilization of glucose.
The oxygen uptake was lower with 20 per cent than with 100 per cent oxygen as gas phase. Small Pasteur and Crabtree effects were demonstrated. The oxygen consumption and lactic acid production proceeded linear with time, while the glucose utilization was higher during the first 30 minutes of incubation than later on.
It is concluded that lymphocytes have a low aerobic glycolysis accounting for 75 per cent of the glucose utilization. The respiration is severely inhibited at high cell concentrations and it is suggested that this is caused by an insufficient availability of oxygen to the cells.