Effect of combined OX40Ig and CTLA4Ig gene local transfer on allograft rejection and the underlying mechanisms.
BACKGROUND
OX40Ig and CTLA4Ig fusion proteins have been suggested to induce immune tolerance and prevent rejection in allografts. The present study aims to investigate and compare the effects of ex vivo combined OX40Ig and CTLA4Ig lentivirus-mediated gene transfer on the long-term survival of the graft, as well as potential underlying mechanisms.


METHODS
We ex vivo transferred Brown Norway rats' superficial groin free flap with lentivirus vectors expressing OX40Ig or CTLA4Ig, or OX40Ig and CTLA4Ig combined, and transplanted the free flaps to Lewis rats. Short-course rapamycin was administered after transfection and transplantation. RT-PCR and Western blot were employed to evaluate expression of OX40Ig and CTLA4Ig. We assessed the survival time of the grafts and the degree of acute graft rejection after indicated treatment. Mixed lymphocyte reaction, flow cytometry, and ELISA were also used to evaluate systemic immune reactions.


RESULTS
Ex vivo transfer of OX40Ig or CTLA4Ig lentivirus vectors led to local expression of corresponding mRNA and proteins in the donor flap without affecting other organs of the recipient. The graft survival time was significantly expanded and rejection was markedly attenuated after transfection. Mixed lymphocyte reaction, flow cytometry (CD4(+) and CD8(+) T lymphocyte proportions), and serum ELISA analysis (IL-2, IFN-γ, IL-4, and IL-10) also showed decreased immune response following transfection. Combined OX40Ig and CTLA4Ig transfer exerted superior effect on improving graft survival and preventing graft rejection, inhibiting the immune response and decreasing the production of proinflammatory cytokines, compared with singular transfer of either OX40Ig or CTLA4Ig.


CONCLUSIONS
Combined ex vivo transfer of OX40Ig and CTLA4Ig lentivirus vectors provided superior benefits on long-term survival and restoration of the graft through inhibiting immune response and decreasing the production of proinflammatory cytokines.
Department of Plastic Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, PR China.
Jin
J
Zhang
Qing
Q
Miao
Yang
Y
Yang
Bo
B
Xiao
Bei
B
Liu
Jiao
J
Cao
Xiao-Yan
XY
Hao
Si-Wang
SW
Wang
Shu-Zhong
SZ
Guo
D000069594:Abatacept; D000818:Animals; D000943:Antigens, Differentiation / Q000235:genetics*; D048749:Cytokinesis; D018014:Gene Transfer Techniques; D015316:Genetic Therapy; D006084:Graft Rejection / Q000517:prevention & control*; D006085:Graft Survival; D018796:Immunoconjugates / Q000235:genetics*; D016086:Lentivirus / Q000235:genetics; D007959:Lymphocyte Culture Test, Mixed; D008297:Male; D011914:Rats, Inbred BN; D011917:Rats, Inbred Lew; D013524:Surgical Flaps; D014184:Transplantation, Homologous
D000943:Antigens, Differentiation; D018796:Immunoconjugates; C406562:OX40Ig; D000069594:Abatacept