Oxidatively modified low density lipoprotein (Ox-LDL) is a known chemoattractant for monocytes. Here we demonstrate, using a modified Boyden chamber assay, that human peripheral blood T lymphocytes, but not B lymphocytes, also respond chemotactically to Ox-LDL, showing a threefold increase over control and an optimum response at 10 micrograms/ml. Copper and endothelial cell-oxidized LDL and beta-VLDL were used and gave similar results. The activity was not chemokinetic and native LDL possessed no chemoattractant activity. The chemoattractant activity was found to reside in the lipid fraction of Ox-LDL. Lysophosphatidylcholine is a major phospholipid component of Ox-LDL and is known to be chemotactic for monocytes. We show that lysophosphatidylcholine is also chemotactic for T lymphocytes with a maximal fourfold increase at 10 microM. Nonmetabolizable analogues of lysophosphatidylcholine had no such chemotactic effect. Thus, Ox-LDL, by virtue of its lysophosphatidylcholine content, may contribute to the recruitment of both T lymphocytes and monocytes into developing atherosclerotic lesions.
H F McMurray, S Parthasarathy, D Steinberg