Study On The Mechanism Of CD4~+CD28~-T Cells Induce Apoptosis Of Vascular Smooth Muscle Cells In Acute Coronary Syndrome

Objective: To study mechanism of CD4+CD28~-T cells inducing apoptosis ofhuman vascular smooth muscle cells (VSMCs) in patients with acute coronarysyndrome (ACS), we assayed whether CD4+CD28~-T cells express tumor necrosisfactor related apoptosis-inducing ligand (TRAIL) in patients with ACS andCD4+CD28~-T cells induce apoptosis of VSMCs through TRAIL pathway.Method: The number of CD4+CD28~-T cells and the expression of TRAIL onCD4+CD28~-T cells were determined by fluorescence-activating cell sorter (FACS).CD4+CD28~-T cells were isolated with MACS, and were cloned with limiting dilutionanalysis. VSMCs were incubated together with CD4+CD28~-T cells, apoptosis ofVSMCs was determined with4’,6-diamidino-2-phenylindole2hci (DAPI staining).Results: The numbers of CD4+CD28~-T cells in peripheral blood of the patientswith ACS were higher than those in control group and SAP group (p<0.01), and theexpression of TRAIL on CD4+CD28~-T cells was significantly higher thanCD4+CD28+T cells (p<0.01). the CD4+CD28~-T cells induce apoptosis of VSMCswas significantly higher than CD4+CD28+T cell at different E/T ratios（5:1and20:1）(p<0.05). Apoptosis of VSMCs decreased when anti-TRAIL antibody was added.Conclusions: The number of the CD4+CD28~-T cells significantly increased andexpress TRAIL in peripheral blood of the patients with ACS. The CD4+CD28~-T cellswere able to induce apoptosis of VSMCs by TRAIL pathway. Expansion ofCD4+CD28~-T cells may affect the stability of arteriosclerosis plaque.