Alloantigen-pulsed host dendritic cells induce T-cell regulation and prolong allograft survival in a rat model of hindlimb allotransplantation.
BACKGROUND
Composite tissue allotransplantation is restricted due to the risks presented by long-term therapeutic immunosuppression. This study is conducted to investigate whether treatment with recipient immature dendritic cells (DCs) pulsed with donor alloantigens can prolong allograft survival and induce T-cell regulation in a rodent model.


METHODS
Orthotopic hindlimb transplants from Brown-Norway (RT1(n)) to Lewis (RT1(1)) rats were performed (day 0). DCs were propagated from the recipient bone marrow and pulsed with the donor alloantigen lysate. Group 1 (control group) did not receive any treatment. Groups 2 and 3 received cyclosporine A (CsA) at a concentration of 10 and 16 mg.kg(-1).day(-1), respectively, on days 0-20 following composite tissue allotransplantation. Group 4 received antilymphocyte serum (i.p. administered 4 d before and 1 d after transplantation) therapy. Group 5 received combined treatment with CsA (10 mg.kg(-1).day(-1), days 0-20) and donor alloantigen-pulsed recipient DCs (i.v. administered on days 7, 14, and 21). Group 6 received combined treatment with CsA (10 mg.kg(-1).day(-1) on days 0-20), antilymphocyte serum (administered i.p. 4 d before and 1 d after transplantation), and DCs (administered i.v. on days 7, 14, and 21). Graft rejection was defined as epidermolysis/desquamation of the donor skin. The mixed lymphocyte reaction was performed to determine the donor T-cell reactivity. Tissue samples were biopsied to analyze the histological changes, and flow cytometry was performed to quantify the donor T-cells.


RESULTS
Allograft survival was significantly prolonged (>200 d) in Group 6 when compared with the other groups (P < 0.001). The mixed lymphocyte reaction performed for Group 6 revealed hyporesponsiveness of the T-cells to donor alloantigens. Flow cytometric analysis in Group 6 revealed a significant increase in the percentage of CD4(+)/CD25(+) and CD4(+)/foxP3(+) T-cells expression, and significant increase in the percentage of donor cells (RT1(n)) in the recipient peripheral blood. Immunohistochemical staining of allo-skin revealed a significant increase in the proportion of CD25(+) cells in the subcutaneous and dermis layers in Group 6, as compared to other groups.


CONCLUSIONS
Treatment with donor alloantigen-pulsed recipient immature DCs in combination with transient immunosuppression prolongs allograft survival and induced tolerance by inducing T-cell hyporesponsiveness to donor alloantigens and increasing the CD4(+)/CD25(+) T-cell population.
Kuo
Yur-Ren
YR
Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Chang Gung University, College of Medicine, Taiwan. t1207816@ms22.hinet.net
Huang
Chong-Wei
CW
Goto
Shigeru
S
Wang
Chun-Ting
CT
Hsu
Li-Wen
LW
Lin
Yu-Chun
YC
Yang
Kuender D
KD
Chen
Chao-Long
CL
Lee
W P Andrew
WP
D000818:Animals; D000961:Antilymphocyte Serum / Q000494:pharmacology / Q000627:therapeutic use; D015704:CD4 Antigens / Q000378:metabolism; D046528:Chimerism; D003131:Combined Modality Therapy; D016572:Cyclosporine / Q000494:pharmacology / Q000627:therapeutic use; D003713:Dendritic Cells / Q000276:immunology*; D006084:Graft Rejection / Q000517:prevention & control; D006085:Graft Survival; D006614:Hindlimb / Q000637:transplantation*; D007165:Immunosuppression Therapy; D007166:Immunosuppressive Agents / Q000494:pharmacology / Q000627:therapeutic use; D053645:Interleukin-2 Receptor alpha Subunit / Q000378:metabolism; D007519:Isoantigens / Q000276:immunology*; D008297:Male; D051381:Rats; D011917:Rats, Inbred Lew; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism; D023001:Transplantation Tolerance; D014184:Transplantation, Homologous
D000961:Antilymphocyte Serum; D015704:CD4 Antigens; D007166:Immunosuppressive Agents; D053645:Interleukin-2 Receptor alpha Subunit; D007519:Isoantigens; D016572:Cyclosporine