A novel strategy for preventing human CD8+ cytotoxic T lymphocyte-mediated cytotoxicity against pig endothelial cells by overexpression of pig cellular FLICE-like inhibitory protein (c-FLIP) gene.
Human CD8+ cytotoxic T lymphocyte (CTL)-mediated cytotoxicity in xenograft recipients is an important obstacle for successful xenotransplantation of pig organs into humans. In our previous study, we demonstrated that xenocytotoxicity of human CD8+ CTL detrimental to pig endothelial cells (PEC) is mediated mainly by the Fas/FasL apoptotic pathway. Furthermore, we developed new methods to prevent this CTL killing by extracellular remodeling using overexpression of human decoy Fas antigen and membrane-bound human FasL on pig xenograft cells. The cellular FLICE-inhibitory protein (c-FLIP), a caspase-8 inhibitor that lacks the cysteine domain, is a negative regulator of death receptor-mediated apoptosis. c-FLIP proteins exist as long (c-FLIP(L)) and short (c-FLIPs) splice variants, both capable of protecting cells from death receptor-mediated apoptosis. In this report, we have demonstrated that both pig c-FLIPs and pig c-FLIP(L) significantly inhibit human CD8+ CTL-mediated xenocytotoxicity toward stably transfected PEC, although the expression level of pig Fas antigen on cell surface was not changed. These data suggested that intracellular remodeling with overexpression of pig c-FLIP in xenograft cells may decrease the innate cellular responses against xenografts, facilitating long-term xenograft survival.
Tanemura
M
M
Department of Surgery, Osaka University Graduate School of Medicine, Osaka, Japan. tanemura@surg1.med.osaka-u.ac.jp
Saga
A
A
Kawamoto
K
K
Matsuda-Minehata
F
F
Manabe
N
N
Deguchi
T
T
Nishida
T
T
Sawa
Y
Y
Ito
T
T
D000818:Animals; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein / Q000235:genetics*; D002460:Cell Line; D003602:Cytotoxicity, Immunologic; D017931:DNA Primers; D018076:DNA, Complementary; D004730:Endothelium, Vascular / Q000166:cytology / Q000276:immunology* / Q000502:physiology; D005786:Gene Expression Regulation / Q000276:immunology; D006085:Graft Survival; D006801:Humans; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013552:Swine; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D014162:Transfection; D014183:Transplantation, Heterologous / Q000276:immunology
D053446:CASP8 and FADD-Like Apoptosis Regulating Protein; D017931:DNA Primers; D018076:DNA, Complementary; D012333:RNA, Messenger