Patterns of transgene expression and viral clearance from the transplanted liver following ex vivo adenovirus-mediated gene transfer.
OBJECTIVE
In the rat liver transplant model, the liver graft can be transduced ex vivo by adenovirus encoding CTLA-4Ig (AdCTLA-4Ig) to achieve high level of immunosuppression in the liver after transplantation. To characterize the pattern of transgene expression following ex vivo gene transfer to the liver and examine whether immunosuppression would promote adenovirus persistence, we followed the life span of vector DNA and transgene expression in the transplanted liver.


METHODS
Rat liver grafts were perfused ex vivo with adenovirus carrying the reporter gene beta-galactosidase (AdlacZ). The period of transgene expression was assessed at predetermined intervals after transplantation into syngeneic, allogeneic or nude (athymic) recipients. Clearance of vector DNA was assessed by PCR analysis of liver DNA after transplantation.


RESULTS
Graft transduction with AdCTLA-4Ig or systemic cyclosporine treatment effectively abrogated the alloimmune response but did not result in sustained lacZ expression. The course of viral DNA clearance from the liver was also unaffected by immunosuppression as was the implied nucleolytic cleavage of viral DNA.


CONCLUSIONS
In the transplant setting, local expression of CTLA-4Ig or systemic immunosuppression does not solve the problem of viral clearance from the liver. Non-adaptive immune mechanisms may have a significant role in the host response to adenovirus after liver transplantation.
Zamir
Gideon
G
Department of Surgery, University of Pennsylvania, Ground Gates, 3400 Spruce Street, Philadelphia, PA 19104, USA.
Gelman
Andrew E
AE
Olthoff
Kim M
KM
Debonera
Fotini
F
Aldeguer
Xavier
X
Shaked
Abraham
A
D000069594:Abatacept; D000256:Adenoviridae / Q000235:genetics*; D000818:Animals; D030801:Animals, Genetically Modified; D001219:Aspartate Aminotransferases / Q000378:metabolism; D001973:Bromodeoxyuridine / Q000378:metabolism; D018796:Immunoconjugates / Q000235:genetics* / Q000276:immunology*; D007763:Lac Operon; D008099:Liver / Q000276:immunology; D016031:Liver Transplantation / Q000401:mortality; D051381:Rats; D011912:Rats, Inbred ACI; D011917:Rats, Inbred Lew; D011923:Rats, Nude; D019076:Transgenes / Q000276:immunology*; D014184:Transplantation, Homologous
D018796:Immunoconjugates; D000069594:Abatacept; D001219:Aspartate Aminotransferases; D001973:Bromodeoxyuridine