METABOLIC CHANGES IN ACTIVATED T-CELLS - AN NMR-STUDY OF HUMAN PERIPHERAL-BLOOD LYMPHOCYTES

Using NMR spectroscopy, we studied purified, human T lymphocytes in a serum‐free medium. Purified cells were entrapped inside agarose beads and induced to proliferate by the mitogens phorbol‐12‐myristate‐13‐acetate and ionomycin. T lymphocytes in standard culture and inside agarose beads exhibit comparable viability, and similar extent and kinetics of DNA synthesis and Interleukin‐2 secretion. 31P‐NMR revealed decreased phosphomonoester and increased phosphodiester content in cells stimulated for two days or longer. 13C‐glucose utilization and 13C‐lactate production rates showed that 85% of the utilized glucose was converted to lactate. 1H‐NMR spectra of the perfusing media indicated that lactate was also produced from substrates other than glucose or glycogen. Glucose accounted for 25% of the lactate produced by quiescent cells, and for 67% of lactate production by stimulated cells. Glycolysis was enhanced 6‐fold within the first 2 hours following stimulation, and 15‐fold by 48 or 96 h. Aerobic lactate production was increased 3‐fold by 48 h, with only a minor enhancement during the first 12 h of stimulation. Our results indicate a shift from mostly aerobic to mostly anaerobic lactate production in T lymphocytes within the first 90 min of the G0 to G1 transition during cell cycle progression. Copyright © 1993 Wiley‐Liss, Inc., A Wiley Company