CD8+ T-Cell depletion and rapamycin synergize with combined coreceptor/stimulation blockade to induce robust limb allograft tolerance in mice.
The growing development of composite tissue allografts (CTA) highlights the need for tolerance induction protocols. Herein, we developed a mouse model of heterotopic limb allograft in a stringent strain combination in which potentially tolerogenic strategies were tested taking advantage of donor stem cells in the grafted limb. BALB/c allografts were transplanted into C57BL/6 mice treated with anti-CD154 mAb, nondepleting anti-CD4 combined to either depleting or nondepleting anti-CD8 mAbs. Some groups received additional rapamycin. Both depleting and nondepleting mAb combinations without rapamycin only delayed limb allograft rejection, whereas the addition of rapamycin induced long-term allograft survival in both combinations. Nevertheless, robust donor-specific tolerance, defined by the acceptance of a fresh donor-type skin allograft and simultaneous rejection of third-party grafts, required initial CD8(+) T-cell depletion. Mixed donor-recipient chimerism was observed in lymphoid organs and recipient bone marrow of tolerant but not rejecting animals. Tolerance specificity was confirmed by the inability to produce IL-2, IFN-gamma and TNF-alpha in MLC with donor antigen while significant alloreactivity persisted against third- party alloantigens. Collectively, these results show that robust CTA tolerance and mixed donor-recipient chimerism can be achieved in response to the synergizing combination of rapamycin, transient CD8(+) T-cell depletion and costimulation/coreceptor blockade.
Li
Z
Z
Institute for Medical Immunology, Université Libre de Bruxelles, Bruxelles, Belgium.
Benghiat
F S
FS
Charbonnier
L Marie
LM
Kubjak
C
C
Rivas
M N
MN
Cobbold
S P
SP
Waldmann
H
H
De Wilde
V
V
Petein
M
M
Schuind
F
F
Goldman
M
M
Le Moine
A
A
D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology*; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000187:drug effects*; D005121:Extremities / Q000637:transplantation*; D006085:Graft Survival / Q000187:drug effects; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D007371:Interferon-gamma / Q000378:metabolism; D007376:Interleukin-2 / Q000378:metabolism; D008212:Lymphocyte Depletion; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D020123:Sirolimus / Q000494:pharmacology*; D013934:Thymectomy; D018183:Transplantation Chimera; D023001:Transplantation Tolerance / Q000187:drug effects*; D014184:Transplantation, Homologous; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D000911:Antibodies, Monoclonal; D007166:Immunosuppressive Agents; D007376:Interleukin-2; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma; D020123:Sirolimus