Idarubicin-145-2C11-F(ab')2 promotes peripheral tolerance and reduces chronic vascular disease in mouse cardiac allografts.
In order to reduce the toxic effects of the T cell activating anti-CD3 monoclonal antibody, 145-2C11, F(ab')2 fragments were prepared by pepsin digestion. These fragments were then used as non-immunosuppressive carriers for the cytotoxic drug idarubicin (IDA), to reduce toxicity of both the monodonal antibodies (mAb) and the drug and to increase the specificity of drug delivery. The IDA-145-2C11 F(ab')2 immunoconjugate was tested for specificity by fluorometry. 145-2C11 intact antibody, 145-2C11 F(ab')2 and IDA conjugates of the antibody and F(ab')2 were used to treat CBA recipients of BALB/c vascularized cardiac allografts. Mice with hearts surviving >100 days were challenged with donor and third party (C57BL/6) skin grafts. Although both antibody and F(ab')2 blocked the binding of 145-2C11-FITC to CBA spleen cells, only the intact antibody caused sustained depletion of CD3 cells in vivo. 145-2C11 F(ab')2 blocked cell surface CD3 within 30 min, but was cleared in 24 h without depletion of CD3 cells from the spleen. In BALB/c to CBA cardiac allografts (rejected in 12-17 days), IDA-145-2C11 F(ab')2 (0.2 mg/20 g mouse i.p. at the time of transplantation) induced >100 days' allograft survival and specific tolerance, in contrast to the equivalent dose of 145-2C11 F(ab')2 (mean survival 25 days). Hearts from IDA-145-2C11 F(ab')2-treated mice at >100 days showed decreased cellular infiltration and less chronic vascular disease than long-surviving hearts from mice treated with an alternative antibody, KT3. Thus, F(ab')2 prepared from 145-2C11 provided a suitable CD3-specific, nonimmunosuppressive carrier for IDA. This immunoconjugate was more effective against both acute and chronic rejection than other conjugates or whole antibody. IDA-145-2C11 F(ab')2 is an effective, nontoxic tolerogen in the mouse cardiac allograft model.
Han
W R
WR
University of Melbourne, Department of Surgery, Royal Melbourne Hospital, Victoria, Australia.
Murray-Segal
L J
LJ
Gershenzon
A
A
Zhang
J G
JG
Hodder
A N
AN
Pietersz
G A
GA
Mottram
P L
PL
D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000627:therapeutic use* / Q000633:toxicity; D000911:Antibodies, Monoclonal / Q000378:metabolism / Q000627:therapeutic use* / Q000633:toxicity; D017252:CD3 Complex / Q000276:immunology / Q000378:metabolism; D002908:Chronic Disease; D003327:Coronary Disease / Q000276:immunology* / Q000473:pathology / Q000517:prevention & control; D006084:Graft Rejection / Q000276:immunology / Q000517:prevention & control; D006085:Graft Survival / Q000276:immunology; D016027:Heart Transplantation / Q000276:immunology* / Q000473:pathology; D015255:Idarubicin / Q000627:therapeutic use* / Q000633:toxicity; D007108:Immune Tolerance / Q000276:immunology*; D018796:Immunoconjugates / Q000627:therapeutic use* / Q000633:toxicity; D007140:Immunoglobulin Fab Fragments / Q000627:therapeutic use*; D051379:Mice; D008815:Mice, Inbred Strains
D000903:Antibiotics, Antineoplastic; D000911:Antibodies, Monoclonal; D017252:CD3 Complex; D018796:Immunoconjugates; D007140:Immunoglobulin Fab Fragments; D015255:Idarubicin