Study on the mechanism of CD4 + CD28-T cells induce apoptosis of vascular smooth muscle cells in acute coronary syndrome

Abstract

Objective To study CD4+CD28-T cells-induced apoptosis of human vascular smooth muscle cells (VSMCs) in patients with acute coronary syndrome (ACS).Methods The number of CD4+CD28-T cells and the expression of TRAIL on CD4+CD28-T cells were determined by a fluorescence-activated cell sorter (FACS).CD4+CD28-T cells were isolated using magnetic sand (MACS).These cells were cloned with limiting dilution analysis.VSMCs were incubated with CD4+CD28-T cells.VSMC apoptosis was detected using 4',6-diamidino-2-phenylindole dihydrochloride (DAPI).Results The number of CD4+CD28-T cells in the peripheral blood of the patients with ACS was higher than those in the control group and those in the stable angina pectoris (SAP) group.The expression of TRAIL on the CD4+CD28-T cells was significantly higher than that on the CD4+CD28-T cells(t =3.54,P ＜0.01).At different effector/target (E/T) ratios,the degree of VSMC apoptosis induced by the CD4+CD28-T cells was significantly higher than that induced by CD4+CD28-T cells(t =6.15,P ＜ 0.05 ;t =5.21,P ＜ 0.05).Apoptosis of VSMCs was decreased when an anti-TRAIL antibody was added(t =3.22,P ＜ 0.01).Conclusions The number of CD4+CD28-T cells expressing TRAIL was significantly increased in the peripheral blood of patients with ACS,CD4+CD28-T cells were able to induce apoptosis of VSMCs through TRAIL pathway.The elevation in the number of CD4+CD28-T cells may affect the stability of atherosclerotic plaques. Key words: Acute coronary syndrome; Vascular smooth muscle cells; CD4+CD28-T cells