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Induction of Chimerism in Rhesus Macaques through Stem Cell Transplant and Costimulation Blockade‐Based Immunosuppression
Author(s) -
Kean L. S.,
Adams A. B.,
Strobert E.,
Hendrix R.,
Gangappa S.,
Jones T. R.,
Shirasugi N.,
Rigby M. R.,
Hamby K.,
Jiang J.,
Bello H.,
Anderson D.,
Cardona K.,
Durham M. M.,
Pearson T. C.,
Larsen C. P.
Publication year - 2007
Publication title -
american journal of transplantation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.89
H-Index - 188
eISSN - 1600-6143
pISSN - 1600-6135
DOI - 10.1111/j.1600-6143.2006.01622.x
Subject(s) - medicine , immunology , stem cell , immunosuppression , transplantation chimera , haematopoiesis , blockade , hematopoietic stem cell transplantation , transplantation , hematopoietic stem cell , biology , receptor , hematopoietic cell , genetics
A strategy for producing high‐level hematopoietic chimerism after non‐myeloablative conditioning has been established in the rhesus macaque. This strategy relies on hematopoietic stem cell transplantation after induction with a non‐myeloablative dose of busulfan and blockade of the IL2‐receptor in the setting of mTOR inhibition with sirolimus and combined CD28/CD154 costimulation blockade. Hematopoietic stem cells derived from bone marrow and leukopheresis products both were found to be successful in inducing high‐level chimerism. Mean peripheral blood peak donor chimerism was 81% with a median chimerism duration of 145 days. Additional immune modulation strategies, such as pre‐transplant CD8 depletion, donor‐specific transfusion, recipient thymectomy or peritransplant deoxyspergualin treatment did not improve the level or durability of chimerism. Recipient immunologic assessment suggested that chimerism occurred amidst donor‐specific down‐regulation of alloreactive T cells, and the reappearance of vigorous T‐mediated alloreactivity accompanied rejection of the transplants. Furthermore, viral reactivation constituted a significant transplant‐related toxicity and may have negatively impacted the ability to achieve indefinite survival of transplanted stem cells. Nevertheless, this chimerism‐induction regimen induced amongst the longest‐lived stem cell chimerism reported to date for non‐human primates and thus represents a platform upon which to evaluate emerging tolerance‐induction strategies.