A Critical Role for TGF-β/Fc and Nonlytic IL-2/Fc Fusion Proteins in Promoting Chimerism and Donor-Specific Tolerance.
Immunoglobulin-cytokine fusion molecules have been shown to be the new generation of immunomodulating agents in transplantation tolerance induction. In the present study, we tested whether immunoregulatory cytokine fusion proteins of IL-10/Fc, TGF-β/Fc, or IL-2/Fc would enhance allogeneic bone marrow cell (BMC) engraftment and promote tolerance induction.



B6 (H2) mice were conditioned with anti-CD154 (MR1) and rapamycin (Rapa) plus 100 cGy total body irradiation (MR1/Rapa/100 cGy) and transplanted with allogeneic B10.D2 (H2) BMC. Recipients were treated with lytic IL-2/Fc, nonlytic IL-2/Fc, TGF-β/Fc, or IL-10/Fc fusion proteins to promote chimerism to induce tolerance.



Donor chimerism was achieved in 20% of recipients conditioned with MR1/Rapa/100 cGy. The addition of TGF-β/Fc (5- or 10-day treatment) or nonlytic IL-2/Fc (10-day treatment) fusion proteins to the conditioning resulted in engraftment in nearly 100% of recipients. In contrast, lytic IL-2/Fc or IL-10/Fc had no effect. The combination of nonlytic IL-2/Fc and TGF-β/Fc had a synergistic effect to promote engraftment and resulted in significantly higher donor chimerism compared with recipients conditioned with TGF-β/MR1/Rapa/100 cGy. Engraftment was durable in the majority of chimeras and increased over time. The chimeras accepted donor skin grafts and promptly rejected third-party skin grafts. Moreover, specific T cell receptor-Vβ5.½ and TCR-Vβ11 clonal deletion was detected in host T cells in chimeras, suggesting central tolerance to donor alloantigens.



Allogeneic BMC engraftment is enhanced with TGF-β/Fc fusion protein treatment. TGF-β/Fc and nonlytic IL-2/Fc exert a synergistic effect in promotion of alloengraftment and donor-specific transplant tolerance, significantly decreasing the minimum total body irradiation dose required.
1 Institute for Cellular Therapeutics, University of Louisville, Louisville, KY. 2 Thomas Starzl Transplant Institute, University of Pittsburgh Medical Center, Pittsburgh, PA.
Hong
H
Xu
Xin Xiao
XX
Zheng
Wensheng
W
Zhang
Yiming
Y
Huang
Suzanne T
ST
Ildstad
D000818:Animals; D016026:Bone Marrow Transplantation / Q000009:adverse effects; D002478:Cells, Cultured; D018920:Coculture Techniques; D019674:Genes, T-Cell Receptor beta / Q000276:immunology; D006084:Graft Rejection / Q000276:immunology / Q000517:prevention & control*; D006085:Graft Survival / Q000187:drug effects*; D007141:Immunoglobulin Fc Fragments / Q000494:pharmacology*; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D007376:Interleukin-2 / Q000494:pharmacology*; D007519:Isoantigens / Q000276:immunology; D008810:Mice, Inbred C57BL; D023421:Models, Animal; D011993:Recombinant Fusion Proteins / Q000494:pharmacology; D020123:Sirolimus / Q000494:pharmacology; D016038:Skin Transplantation / Q000009:adverse effects; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology; D013997:Time Factors; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D018183:Transplantation Chimera; D019172:Transplantation Conditioning / Q000379:methods*; D023001:Transplantation Tolerance / Q000187:drug effects*; D014184:Transplantation, Homologous; D014916:Whole-Body Irradiation
D007141:Immunoglobulin Fc Fragments; D007166:Immunosuppressive Agents; D007376:Interleukin-2; D007519:Isoantigens; D011993:Recombinant Fusion Proteins; D016212:Transforming Growth Factor beta; D020123:Sirolimus