A novel recombinant immunotoxin with the smallest ribosome-inactivating protein Luffin P1: T-cell cytotoxicity and prolongation of allograft survival.
In the creation of stable tolerance to MHC-incompatible allografts, reducing the large mass of donor-reactive cells via apoptosis is often required. Apoptosis induction by immunotoxins targeting surface molecules specifically presented on donor-reactive cytopathic T effector (T(eff)) cells is a promising strategy. Traditionally, the toxin moieties are bacterial exotoxins or plant-derived ribosome-inactivating proteins (RIPs) with large molecular size and strong immunogenicity, hence causing the problems of tissue penetration, host immune reaction and quick clearance. We have identified a novel class of small molecule RIPs (<10 kD) from the seeds of the plant Luffa cylindrica. The smallest member of this family, Luffin P1, has a molecular weight of 5226.8 Da, yet possessing a highly potent inhibitory activity on cell-free protein synthesis with IC50 of 0.88 nM. We now report a recombinant hIL-2-Luffin P1 immunotoxin, which strongly inhibited T-cell proliferation in mixed lymphocyte reaction and ConA response with IC50 of 1.8-10 nM. In vivo, hIL-2-Luffin P1 significantly prolonged the survival of major MHC-mismatched skin and kidney allografts in animal models. Thus, we demonstrate for the first time the efficacy of the smallest immunotoxin that could be further combined with other pharmacological and immunological reagents for synergistic control of pathogenic lymphocytes in immune-mediated diseases.
Wang
Rupeng
R
Chongqing Key Lab for Diseases Proteomics, Institute of Burn Research, Southwest Hospital, Third Military Medical University, Chongqing, China.
Gan
Chenjun
C
Gao
Wenda
W
He
Weifeng
W
Wang
Xiaojuan
X
Peng
Yanmeng
Y
Zhuo
Junyi
J
Tan
Jianglin
J
Peng
Xu
X
Wu
Jun
J
Luo
Gaoxing
G
D000595:Amino Acid Sequence; D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D006085:Graft Survival / Q000187:drug effects / Q000276:immunology; D006801:Humans; D000922:Immunotoxins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D007376:Interleukin-2 / Q000235:genetics / Q000378:metabolism; D016030:Kidney Transplantation; D029776:Luffa / Q000737:chemistry; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D054788:Ribosome Inactivating Proteins / Q000235:genetics / Q000378:metabolism*; D016038:Skin Transplantation; D013997:Time Factors; D014184:Transplantation, Homologous
D000922:Immunotoxins; D007376:Interleukin-2; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; D054788:Ribosome Inactivating Proteins