Prolonged cardiac allograft survival in presensitized rats after a high activity Yunnan-cobra venom factor therapy.
Complement-dependent antibody-mediated acute humoral rejection is the major obstacle of clinical transplantation across ABO incompatibility and human leukocyte antigen presensitization. We previously demonstrated that Yunnan-cobra venom factor (Y-CVF) could almost completely abrogate complement activity and successfully prevent hyperacute rejection in some xenotransplant models without any obvious toxicity. In this study we investigated whether depletion of complement by Y-CVF prevented acute humoral allograft rejection in presensitized rats thereby prolonging graft survival.


METHODS
Presensitization was achieved in Lewis rats by sequential grafting of three full-thickness skin pieces from Brown Norway rats. Serum cytotoxic alloantibody titers were determined by a modified in vitro complement-dependent microcytotoxicity assay. After presensitization, each Lewis rat received a heterotopic Brown Norway cardiac allograft. Fifteen recipients were divided into two groups: (1) no treatment control (n = 7); (2) Y-CVF therapy group (86 u/kg, IV, day -1) (n = 8). After cessation of the heart beat, allograft rejection was confirmed by pathologic as well as IgG and C3 immunohistochemical examinations.


RESULTS
The mean graft survival time was significantly prolonged to 99.50 +/- 38.72 hours among rats that received Y-CVF vs 12.71 +/- 13.94 hours in nontreated controls (P < .001). Upon pathological and immunohistochemical examination, acute humoral rejection was mainly exhibited in the control group, whereas acute cellular rejection was mainly displayed in the Y-CVF therapy group.


CONCLUSIONS
Our study demonstrated that complement depletion by Y-CVF significantly inhibited acute humoral allograft rejection in presensitized rats. As a therapeutic immunointervention tool for complement, Y-CVF has shown potential efficacy across ABO incompatible and positive cross-match barriers.
Li
R
R
Institute of Organ Transplantation, Key Laboratory of Organ Transplantation (HUST), Ministry of Education, Key Laboratory of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
Chen
G
G
Guo
H
H
Wang
D W
DW
Xie
L
L
Wang
S S
SS
Wang
W Y
WY
Xiong
Y L
YL
Chen
S
S
D000818:Animals; D000917:Antibody Formation / Q000187:drug effects; D002681:China; D004546:Elapid Venoms / Q000627:therapeutic use*; D006085:Graft Survival / Q000187:drug effects / Q000276:immunology*; D016027:Heart Transplantation / Q000276:immunology*; D007114:Immunization; D007518:Isoantibodies / Q000097:blood; D023421:Models, Animal; D051381:Rats; D011914:Rats, Inbred BN; D011917:Rats, Inbred Lew; D016038:Skin Transplantation / Q000276:immunology*; D014184:Transplantation, Homologous
D004546:Elapid Venoms; D007518:Isoantibodies