In order to make xenotransplantation clinically feasible, methodologies to achieve specific immunological tolerance to donor antigens are likely to be needed. Donor-specific tolerance can be induced across allogeneic and closely related xenogeneic barriers by establishment of donor hematopoiesis in the recipient. However, studies in both concordant and discordant xenogeneic species combinations have revealed that non-immunologic barriers such as species differences in the growth factors and adhesive interactions which comprise the hematopoietic environment, limit the establishment and efficacy of hematopoiesis. The applicants have obtained evidence that the provision of donor species-specific cytokines can enhance donor hematopoiesis in a xenogeneic environment, and that adhesive receptor ligand interactions critical to hematopoiesis may also vary between species. The applicants intend to define the critical factors that are likely to limit porcine hematopoiesis in human recipients, with the aim of optimizing conditions to achieve tolerance in the swine to human species combination. In this application, the applicants will develop reagents to identify and isolate porcine long-term multilineage repopulating pluripotent hematopoietic stem cells. The capacity of putative stem cell enriched porcine hematopoietic cells to self renew and differentiate will be examined in vitro and in vivo stem cell transplantation studies in both homologous and xenogeneic recipients. The capacity of porcine adhesion molecules to direct relevant cell-cell interactions between swine hematopoietic progenitors and human stromal elements will be analyzed. Moreover, the role of the alpha-gal carbohydrate modification in the biology of hematopoiesis will be explored in vitro in clonogenic assays and by utilizing alpha-1,3gal knockout mice in in vivo studies. It is anticipated that the results of these studies will provide information which will guide the development of transgenic pigs whose hematopoietic cells can function in human recipients, and which can thereby reliably induce durable tolerance for swine to human xenotransplantation.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL054038-06
Application #
6043839
Study Section
Special Emphasis Panel (ZRG2-ET-1 (03))
Project Start
1994-08-01
Project End
2003-07-31
Budget Start
1999-08-01
Budget End
2000-07-31
Support Year
6
Fiscal Year
1999
Total Cost
Indirect Cost
Name
Massachusetts General Hospital
Department
Type
DUNS #
City
Boston
State
MA
Country
United States
Zip Code
02199
Giovino, Maria A; Wang, Hui; Sykes, Megan et al. (2005) Role of VLA-4 and VLA-5 in ex vivo maintenance of human and pig hematopoiesis in human stroma-supported long-term cultures. Exp Hematol 33:363-70
Lan, Ping; Wang, Lan; Diouf, Bintou et al. (2004) Induction of human T-cell tolerance to porcine xenoantigens through mixed hematopoietic chimerism. Blood 103:3964-9
Eguchi, Hiroshi; Knosalla, Christoph; Lan, Ping et al. (2004) T cells from presensitized donors fail to cause graft-versus-host disease in a pig-to-mouse xenotransplantation model. Transplantation 78:1609-17
Le Guern, Annie C; Giovino, Maria A; Abe, Masahiro et al. (2003) Stem cell activity of porcine c-kit+ hematopoietic cells. Exp Hematol 31:833-40
Heinz, Matthew; Huang, Christene A; Emery, David W et al. (2002) Use of CD9 expression to enrich for porcine hematopoietic progenitors. Exp Hematol 30:809-15
Giovino, Maria A; Down, Julian D; Jackson, John D et al. (2002) Porcine hematopoiesis on primate stroma in long-term cultures: enhanced growth with neutralizing tumor necrosis factor-alpha and tumor growth factor-beta antibodies. Transplantation 73:723-31
Sykes, M; Sachs, D H (2001) Mixed chimerism. Philos Trans R Soc Lond B Biol Sci 356:707-26
Wekerle, T; Sykes, M (2001) Mixed chimerism and transplantation tolerance. Annu Rev Med 52:353-70
Abe, M; Chen, A M; Qi, J et al. (2000) Porcine stem cell factor facilitates long-lasting porcine hematopoietic engraftment in murine recipients. Transplant Proc 32:1047
Warrens, A N; Simon, A R; Theodore, P R et al. (2000) Cross-species compatibility of intercellular adhesion molecule-1 (CD54) with its ligands. Transplantation 69:394-9

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