Influence of different stimuli on expression of apoptosis inducing ligands of CD4+T cells

    HAN Weiª²Ning, CAO Yunª²Xin, ZHANG Yun, LI Qi, Liu Xueª²Song, JIN Boª²Quan

    Department of Immunology, School of Basic Medicine, Fourth Military Medical University, Xi¬ðan 710033, China

    ¡¾Abstract¡¿AIM: To investigate the influence of different stimuli on the cell membrane and intracellular expression of apoptosisª²inducing ligands (TRAIL, FasL and TNFª²¦Á) of CD4+T cells. METHODS: PBMCs were stimulated by Staphylococcus enterotoxin B (SEB), phorbol myristate acetate (PMA), phytohemagglutinin (PHA) and alloantigen on EB virusª²transformed B lymphoblastoid cells. The membrane and intracellular expressions of apoptosis inducing ligands were examined by immunofluorescence staining and threeª²color flow cytometry analysis. RESULTS: ¢Ù The expression of membrane FasL of the resting CD4+T cells was almost negative and PMA and PHA could induce FasL expression. The intracellular FasL expressed at a certain level in resting CD4+T cells and PMA, PHA and alloantigen downregulated the expression. ¢Ú The expression of membrane TRAIL on the resting CD4+T cell was negative and SEB upregulated its expression slightly. TRAIL expressed at a low level in cytoplasm. SEB and alloantigen upregulated its expression slightly whereas PHA downregulated the expression. ¢Û The expression of membrane TNFª²¦Á on the resting CD4+T cell was undetectable and PMA and PHA upregulated the expression. TNFª²¦Á expressed at a moderate level in cytoplasm and SEB and alloantigen upregulated its expression significantly. CONCLUSION: FasL, TRAIL and TNFª²¦Á are all important effector molecules of T helper (Th) cells and the expression of these apoptosisª²inducing ligands both on the membrane and in the cells is regulated by different stimuli. ......