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B7‐H1 induced Apoptosis on Epstein‐Barr Virus transformed B cells through Fas‐Fas Ligand expression
Author(s) -
Park GaBin,
Kim YeongSeok,
Song Hyunkeun,
Lee HyunKyung,
Lee Wang Jae,
Hur Dae Young
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.1079.11
Subject(s) - fas ligand , apoptosis , flow cytometry , microbiology and biotechnology , biology , t cell , western blot , chemistry , programmed cell death , immunology , immune system , biochemistry , gene
B7‐H1 encompasses a recently discovered cell surface glycoprotein within the B7 family of T‐cell co‐regulatory molecules. Some human tumors acquire the ability to aberrantly express B7‐H1. Tumor‐associated B7‐H1, as well as B7‐H1 on activated lymphocytes, has been shown to impair antigen‐specific T‐cell function and survival in vitro. In contrast, the monoclonal antibody‐mediated stimulation of B7‐H1(reverse signaling) on cancer cells expressing B7‐H1 molecule itself has not been studied. Our group has recently reported that B7‐H1 is induced on EBV‐transformed B cells via immunohistochemical staining and flow cytometric analysis. In addition, We observed that B7‐H1 ligation with anti‐B7‐H1 mAb enhanced the apoptosis of EBV‐transformed B cells. And B7‐H1 ligation induced the expression of both FasL and Fas in theses cells. Furthermore, anti‐Fas blocking antibody, ZB4, blocked B7‐H1‐mediated apoptosis effectively and caspase inhibitors also effectively blocked B7‐H1‐induced cell death. Western blot analysis showed down‐regulated expression of procaspase‐8, 3 and PARP. The release of cytochrome c and translocation to nucleus of endoG and AIF were showed by confocal micoscopy. The findings suggested that Fas/FasL pathway was activated by B7‐H1 ligation on EBV‐transformed B cells.