THE GENERATION OF H-1-NMR-DETECTABLE MOBILE LIPID IN STIMULATED LYMPHOCYTES - RELATIONSHIP TS CELLULAR ACTIVATION, THE CELL-CYCLE, AND PHOSPHATIDYLCHOLINE-SPECIFIC PHOSPHOLIPASE-C

Mobile Lipids detected using H-1-NMR in stimulated lymphocytes were co rrelated with cell cycle phase, expression of the interleukin-2 recept or alpha and proliferation to assess the activation status of the lymp hocytes. Mobile lipid levels, IL-2R alpha expression and proliferation increased after treatment with PMA and ionomycin. PMA or ionomycin st imulation alone induced increased IL-2R alpha expressiom but not proli feration, PMA- but not ionomycin-stimulation generated mobile lipid, T reatment with anti-CD3 antibody did not increase IL-2R alpha expressio n or proliferation but did generate increased amounts of mobile lipid, The cell cycle status of thymocytes treated with anti-CD3, PMA or ion omycin alone indicated an. accumulation of the cells in the G(1) phase of the cell cycle, The generation of mobile lipid was abrogated in an ti-CD3 antibody-stimulated thymic lymphocytes but not in splenic lymph ocytes, using a phosphatidylcholine-specific phospholipase C (PC-PLC) inhibitor which blocked cells in the G(1)/S phase of the cell cycle, T his suggests that the H-1-NMR-detectable mobile Lipid may be generated in anti-CD3 antibody-stimulated thymic lymphocytes by the action of P C-PLC activity via the catabolism of PC, in the absence of classical s igns of activation. (C) 1997 Academic Press.