Lipid requirements of human T lymphocytes stimulated with mitogen in serum-free medium. Membrane "fluidity" changes are an artefact of lipid (AL721) uptake by monocytes.
A correlation has been sought between the effects of lipids on membrane fluidity and mitogen responsiveness of human peripheral blood lymphocytes (PBL). Cholesterol and the reputedly potent membrane fluidizing agent AL721 (1) were used for these studies. However, the large AL721 induced increase in membrane "fluidity", assessed by steady state polarization of the probe 1,6-diphenyl-1,3,5-hexatriene (DPH), was found to be an artefact arising from lipid uptake by monocytes. Mitogen responses were enhanced by AL721 but unaffected by cholesterol. It is concluded that AL721 does not exert its effect through enhanced triggering of cells by altered membrane fluidity but rather that lymphocytes require an exogenous source of phospholipids/triglycerides for optimal growth in vitro, although they can synthesize sufficient cholesterol to meet their own needs.
Traill
K N
KN
Institute for General and Experimental Pathology, University of Innsbruck, Medical School, Austria.
Offner
F
F
Winter
U
U
Paltauf
F
F
Wick
G
G
D000328:Adult; D001692:Biological Transport; D002478:Cells, Cultured; D003470:Culture Media; D004261:DNA Replication; D004338:Drug Combinations / Q000378:metabolism; D005260:Female; D005455:Fluorescent Antibody Technique; D005989:Glycerides / Q000378:metabolism*; D006684:HLA-DR Antigens / Q000032:analysis; D006801:Humans; D008213:Lymphocyte Activation; D008297:Male; D008560:Membrane Fluidity; D009000:Monocytes / Q000502:physiology; D010713:Phosphatidylcholines / Q000378:metabolism*; D010714:Phosphatidylethanolamines / Q000378:metabolism*; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000502:physiology
D003470:Culture Media; D004338:Drug Combinations; D005989:Glycerides; D006684:HLA-DR Antigens; D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; C046637:neutral lipid, phosphatidylcholine, phosphatidylethanolamine drug combination