Adenoviral-mediated overexpression of membrane-bound human FasL and human decoy Fas protect pig islets against human CD8+ CTL-mediated cytotoxicity.
Pig islets are considered to be most suitable source of islets for xenotransplantation into patients with type 1 diabetes mellitus. However, cellular rejection, especially CD8+ CTL-mediated cytotoxicity, remains a formidable barrier preventing long-term xenograft survival. Our previous study demonstrated that human CD8+ CTLs were highly detrimental to xenograft cells and that this strong cytotoxicity of human CTLs was mediated mainly by the Fas/FasL apoptotic pathway. Furthermore, we exploited novel methods for inhibiting human CD8+ CTL-mediated xenocytotoxicity with overexpression of membrane-bound human FasL and human decoy Fas antigen in xenografted cells. In the present study, we assessed the cytoprotective effects of these novel inhibitory molecules overexpressed by an adenoviral-mediated system in pig islets. Isolated pig islets were transfected with adenovirus vector encoding either human decoy Fas or membrane-bound human FasL genes. Thirty percent to 60% of transfected pig islets expressed these molecules producing 60% to 88% suppression of CTL killing compared with parental pig islets. These data indicated that pig islet grafts isolated from transgenic pigs with either membrane-bound human FasL or human decoy Fas antigen genes may control the innate cellular response to xenografts, and creating a window of opportunity to facilitate xenograft survival.
Kawamoto
K
K
Department of Surgery, Osaka University Graduate School of medicine, Osaka, Japan.
Tanemura
M
M
Komoda
H
H
Omori
T
T
Fumimoto
Y
Y
Shimada
K
K
Deguchi
T
T
Saga
A
A
Kakuda
A
A
Nishida
T
T
Sawa
Y
Y
Ito
T
T
D000256:Adenoviridae / Q000235:genetics*; D000818:Animals; D003602:Cytotoxicity, Immunologic; D053222:Fas Ligand Protein / Q000235:genetics*; D006801:Humans; D007515:Islets of Langerhans / Q000276:immunology*; D017710:Lymphocyte Transfusion; D013552:Swine; D013602:T-Lymphocytes, Cytotoxic / Q000637:transplantation*; D014162:Transfection; D014183:Transplantation, Heterologous; D019014:fas Receptor / Q000235:genetics*
D053222:Fas Ligand Protein; D019014:fas Receptor