Bone marrow transplantation from alpha1,3-galactosyltransferase gene-knockout pigs in baboons.
BACKGROUND
Successful hematopoietic cell allotransplantation results in donor-specific tolerance, but this approach has been unsuccessful in the wild-type pig-to-baboon xenotransplantation model, as pig cells were lost from the circulation within 5 days. However, after cessation of immunosuppressive therapy on day 28, all baboons demonstrated non-specific unresponsiveness on mixed leukocyte reaction (MLR) for at least 30 days. We have now investigated the transplantation of bone marrow (BM) cells from miniature swine homozygous for alpha1,3-galactosyltransferase gene-knockout (GalT-KO).


METHODS
Baboons (n = 3) were pre-treated with whole body and thymic irradiation, anti-thymocyte globulin, and splenectomy, and received immunosuppressive and supportive therapy for 28 days. BM was harvested from GalT-KO swine (n = 3). The baboons were monitored for the presence of pig cells by flow cytometry and colony-forming units (CFUs), and for cellular reactivity by MLR.


RESULTS
A mean of 11 x 10(8) BM cells/kg was infused into each baboon. The mean absolute numbers and percentages of pig cells detected in the blood at 2 h and on days 1, 2 and 4, respectively, were 641/microl (9.5%), 132/microl (3.4%), 242/microl (3.9%), and 156/microl (2.9%). One baboon died (from accidental hemorrhage) on day 6, at which time chimerism was present in the blood (2.0%) and BM (6.4%); pig cell engraftment in the BM was confirmed by polymerase chain reaction (PCR) of CFUs. In the two other baboons, blood chimerism was lost after day 5 but returned at low levels (<1%) between days 9 to 16 and 7 to 17, respectively, indicating transient BM engraftment. Both surviving baboons showed non-specific unresponsiveness on MLR until they were euthanized on days 85 and 110, respectively.


CONCLUSIONS
By using BM cells from GalT-KO pigs, chimerism was detected at levels comparable with previous studies when 30-fold more growth factor-mobilized peripheral blood progenitor cells had been transplanted. In addition, cellular hyporesponsiveness was prolonged. However, long-term engraftment and chimerism were not achieved.
Tseng
Y-L
YL
Transplantation Biology Research Center, Massachusetts General Hospital/Harvard Medical School, Boston, MA 02129, USA.
Dor
F J M F
FJ
Kuwaki
K
K
Ryan
D
D
Wood
J
J
Denaro
M
M
Giovino
M
M
Yamada
K
K
Hawley
R
R
Patience
C
C
Schuurman
H-J
HJ
Awwad
M
M
Sachs
D H
DH
Cooper
D K C
DK
D000818:Animals; D030801:Animals, Genetically Modified; D000906:Antibodies / Q000276:immunology; D001853:Bone Marrow / Q000276:immunology; D016026:Bone Marrow Transplantation / Q000276:immunology; D046528:Chimerism; D005700:Galactosyltransferases / Q000172:deficiency* / Q000235:genetics* / Q000276:immunology; D017353:Gene Deletion; D007962:Leukocytes / Q000276:immunology; D007959:Lymphocyte Culture Test, Mixed; D010215:Papio / Q000276:immunology; D016133:Polymerase Chain Reaction; D013552:Swine / Q000235:genetics; D019172:Transplantation Conditioning; D014183:Transplantation, Heterologous
D000906:Antibodies; D005700:Galactosyltransferases; C047006:N-acetyllactosaminide alpha-1,3-galactosyltransferase