Adoptive transfusion of ex vivo donor alloantigen-stimulated CD4(+)CD25(+) regulatory T cells ameliorates rejection of DA-to-Lewis rat liver transplantation.
BACKGROUND
Adoptive transfusion of splenocytes from long-term survivors of a tolerance model of rat orthotopic liver transplantation can induce acceptance of liver allografts in a rejection model preconditioned with donor gamma-irradiation before liver transplantation. Recent studies suggest that the regulatory T cells (Treg cells) in splenocytes from long-term survivors play an important role in the induction of liver graft tolerance, but this observation was made from a rejection model preconditioned with donor gamma-irradiation; little is known about the role of Treg cells in liver graft rejection using a naive rejection model. In this study, we examined the therapeutic potential of CD4(+)CD25(+) Treg cells in a naive rejection model of rat liver transplantation.


METHODS
Freshly isolated or ex vivo alloantigen-stimulated CD4(+)CD25(+) Treg cells (1 x 10(6) cells) from naive Lewis RT(1) (LEW) rats were adoptively transferred into another LEW rat on days 1 and 7 after liver transplantation from a Dark Agouti RT1(a) (DA) rat. Recipients were treated with or without oral tacrolimus (FK506) (0.1 mg/kg/day) from days 1 to 7 after transplantation. For ex vivo alloantigen-stimulation, CD4(+)CD25(+) Treg cells from LEW rats were cocultured with mitomycin C-treated DA (donor alloantigen specific) or Brown Norway (BN)(RT1(n), third party) splenocytes for 72 hours. Ex vivo alloantigen-specific CD4(+)CD25(-) T-cell proliferation responses were assessed with fresh and stimulated CD4(+)CD25(+) Treg cells.


RESULTS
Freshly isolated, donor alloantigen-stimulated and third-party alloantigen- stimulated CD4(+)CD25(+) Treg cells suppressed antigen-specific CD4(+)CD25(-) T-cell proliferation ex vivo, and adoptive transfusion of these 3 kinds of CD4(+)CD25(+) Treg cells prolonged survival of the liver allografts. The group transfused with the donor alloantigen-stimulated CD4(+)CD25(+) Treg cells had the greatest mean survival among the 3 groups (fresh Treg cells, 21 +/- 2 days, n = 6; third-party alloantigen-stimulated Treg cells, 20 +/- 2 days, n = 6; donor alloantigen-stimulated Treg cells, 30 +/- 2 days, n = 6). When combined with short-term tacrolimus administration, adoptive transfusion of donor antigen-stimulated Treg cells induced the greatest survival time in recipients (greater than 60 days; n = 6).


CONCLUSIONS
Adoptive transfusion of ex vivo donor alloantigen-stimulated CD4(+)CD25(+) Treg cells combined with short-term tacrolimus treatment may represent a new strategy for preventing rejection after liver transplantation.
Pu
Li-Yong
LY
Liver Transplantation Center, First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
Wang
Xue-Hao
XH
Zhang
Feng
F
Li
Xiang-Cheng
XC
Yao
Ai-Hua
AH
Yu
Yue
Y
Lv
Ling
L
Li
Guo-Qiang
GQ
D019264:Adoptive Transfer; D000818:Animals; D049109:Cell Proliferation; D006084:Graft Rejection / Q000503:physiopathology*; D006085:Graft Survival / Q000187:drug effects; D007166:Immunosuppressive Agents / Q000494:pharmacology; D053645:Interleukin-2 Receptor alpha Subunit / Q000378:metabolism*; D007519:Isoantigens / Q000276:immunology*; D016031:Liver Transplantation; D017710:Lymphocyte Transfusion; D051381:Rats; D011917:Rats, Inbred Lew; D011919:Rats, Inbred Strains; D050378:T-Lymphocytes, Regulatory / Q000166:cytology / Q000276:immunology* / Q000378:metabolism*; D016559:Tacrolimus / Q000494:pharmacology; D013997:Time Factors; D014184:Transplantation, Homologous
D007166:Immunosuppressive Agents; D053645:Interleukin-2 Receptor alpha Subunit; D007519:Isoantigens; D016559:Tacrolimus