Immunological inhibition of transplanted liver allografts by adeno-associated virus vector encoding CTLA4Ig in rats.
BACKGROUND
Blockade interaction between CD28 and B7 with CTLA4Ig has been shown to induce experimental transplantation tolerance. In order to prolong the inhibitory effect of CTLA4Ig, a recombinant adeno-associated virus vector pSNAV expressing CTLA4Ig was constructed, and its effects on transplanted liver allografts were investigated.


METHODS
The pSNAV-CTLA4Ig construct was infused into partial liver allografts of rats via the portal vein during transplantation. CTLA4Ig expression in the transplanted livers was detected with reverse transcriptase-polymerase chain reaction (RT-PCR) analysis and immunohistochemistry. Furthermore, real-time quantitative PCR was used to measure the expression of IL-2, IFN-gamma, IL-4 and IL-10 in the allografts.


RESULTS
The expression of CTLA4Ig in the partial allograft was detected successfully and pSNAV-CTLA4Ig improved the survival rate of rats after liver transplantation. Agarose gel analysis of RT-PCR products indicated the presence of CTLA4Ig in the pSNAV-CTLA4Ig treatment group. Cytokines expressed in allografts on day 7 after orthotopic liver transplantation showed that IL-2, IFN-gamma, IL-4 and IL-10 mRNA levels decreased in transplant recipients treated with pSNAV-CTLA4Ig compared with those treated with pSNAV-LacZ (1.62+/-0.09, 1.52+/-0.11, 1.50+/-0.07 and 1.43+/-0.07 versus 1.29+/-0.09, 1.32+/-0.07, 1.34+/-0.06 and 1.35+/-0.04, respectively).


CONCLUSIONS
pSNAV-CTLA4Ig effectively expressed CTLA4Ig in liver allografts. CTLA4Ig improved the pathological findings after liver transplantation. CTLA4Ig induced immune tolerance of liver transplantation, and the mechanism involved induced alteration of Th1 and Th2 cytokine transcripts. The adeno-associated virus vector encoding CTLA4Ig may be useful in the clinical study of transplantation tolerance.
Lu
Sen
S
Center of Liver Transplantation, First Affiliated Hospital, Nanjing Medical University, Nanjing 210029, China.
Yu
Yue
Y
Gao
Yun
Y
Li
Guo-Qiang
GQ
Wang
Xue-Hao
XH
D000069594:Abatacept; D000818:Animals; D004273:DNA, Neoplasm / Q000235:genetics*; D000229:Dependovirus / Q000235:genetics*; D004195:Disease Models, Animal; D015972:Gene Expression Regulation, Neoplastic; D005822:Genetic Vectors; D006084:Graft Rejection / Q000235:genetics* / Q000276:immunology; D007108:Immune Tolerance; D018796:Immunoconjugates / Q000235:genetics*; D016031:Liver Transplantation / Q000276:immunology*; D008297:Male; D051381:Rats; D011917:Rats, Inbred Lew; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014184:Transplantation, Homologous; D014409:Tumor Necrosis Factor-alpha
D004273:DNA, Neoplasm; D018796:Immunoconjugates; D014409:Tumor Necrosis Factor-alpha; D000069594:Abatacept