title: Recombinant adeno-associated virus vector: Is it ideal for gene delivery in liver transplantation?
abstract: Recombinant adeno-associated virus vector (rAAV) is an effective and safe gene-delivery tool. However, its application in solid-organ transplantation has not been addressed. The present study is designed to introduce human cytotoxic T-lymphocyte-associated antigen 4 immunoglobulin G (hCTLA4Ig) by rAAV (rAAV-hCTLA4Ig) into rat liver grafts to analyze the effects of virus titer, exposure time, and route of administration on transgene expression and possible side effects caused by the gene-delivery approach. Different rAAV-hCTLA4Ig titers were introduced into liver grafts through back-table portal vein perfusion and preserved for a certain time. rAAV-hCTLA4Ig also was administered by intravenous and intramuscular injection. Transgene expression in grafts and plasma was detected by immunohistochemistry and enzyme-linked immunosorbent assay. Intragraft cytokine level was detected by reverse-transcriptase polymerase chain reaction. Anti-hCTLA4Ig antibodies in plasma were detected by flow cytometry. A higher virus titer (1 x 10(12) viral genomes/animal) introduced through back-table portal vein perfusion and a longer preservation time (3 hours) achieved a greater level of transgene expression until day 180. Back-table portal vein perfusion induced a greater level of hCTLA4 expression in plasma than intramuscular or intravenous injection. Increased interleukin-2 and interferon-gamma messenger RNA levels were detected in grafts with rAAV-hCTLA4Ig gene transfer compared with those without virus delivery, but the response was minor. Such a cellular immune response could be suppressed by low-dose FK506 administration during the first 3 postoperative days. Anti-hCTLA4Ig antibodies could be detected in long-term surviving animals, but the extent of humoral response was not severe. This study shows that rAAV can be an effective and safe vector for gene delivery in liver transplantation.
authors.affiliation: Centre for the Study of Liver Disease and Department of Surgery, University of Hong Kong Medical Centre, Queen Mary Hospital, China.
authors.forename: Zhen-Fan
authors.initials: ZF
authors.lastname: Yang
authors.forename: Xiao-Bing
authors.initials: XB
authors.lastname: Wu
authors.forename: Tung-Yu
authors.initials: TY
authors.lastname: Tsui
authors.forename: Yun-De
authors.initials: YD
authors.lastname: Hou
authors.forename: John M
authors.initials: JM
authors.lastname: Luk
authors.forename: Sheung-Tat
authors.initials: ST
authors.lastname: Fan
mesh_terms: D000818:Animals; D000917:Antibody Formation; D015703:Antigens, CD; D000943:Antigens, Differentiation / Q000235:genetics / Q000276:immunology; D060908:CTLA-4 Antigen; D000229:Dependovirus / Q000235:genetics*; D015870:Gene Expression; D018014:Gene Transfer Techniques; D005822:Genetic Vectors / Q000592:standards*; D006085:Graft Survival; D006801:Humans; D007111:Immunity, Cellular; D008099:Liver / Q000473:pathology; D016031:Liver Transplantation; D008297:Male; D051381:Rats; D011917:Rats, Inbred Lew; D011995:Recombination, Genetic
chemical_list: D015703:Antigens, CD; D000943:Antigens, Differentiation; D060908:CTLA-4 Antigen; C556706:CTLA4 protein, human; C556708:Ctla4 protein, rat