Use of lentiviral vectors to induce long-term tolerance to gal(+) heart grafts.
BACKGROUND
Tolerance to organ grafts has been achieved by establishing a state of stable mixed-cell chimerism after bone marrow transplantation. Gene therapy has been applied to establish chimerism for cells expressing galactose alpha 1,3 galactose in alpha 1,3 galactosyltransferase deficient (gal knockout) mice using retroviral vectors. Limitations to the success of this methodology include short-term expression of the introduced gene and rejection of gal hearts transplanted into these animals within a month.


METHODS
Autologous bone marrow from gal knockout mice was transduced with a lentiviral vector expressing porcine alpha 1,3 galactosyltransferase and transplanted into lethally irradiated gal knockout mice. Chimerism was monitored by flow cytometry. Hearts from wild type mice (gal/) were transplanted into these animals and palpated daily. Xenoantibodies directed at the gal carbohydrate or porcine xenoantigens were detected by enzyme-linked immunosorbent assay.


RESULTS
Hearts from wild-type gal/ donors were permanently accepted in all mice receiving autologous, transduced bone marrow before heart transplantation. Control mice rejected gal hearts within 12 to 14 days. Histologic analysis demonstrated classical signs of rejection in controls and normal myocardium with no evidence of rejection in mice chimeric for the gal carbohydrate. Anti-gal xenoantibodies were not produced in gal chimeras, but normal antibody responses to other xenoantigens were detected. Specific tolerance for the gal carbohydrate was achieved by this procedure.


CONCLUSIONS
These experiments report the first demonstration of permanent survival of gal hearts after transplantation with autologous, transduced bone marrow. Transduction with lentiviral vectors results in long-term, stable chimerism at levels sufficient to induce long-term tolerance to heart grafts in mice.
Kearns-Jonker
Mary
M
Department of Cardiothoracic Surgery, Children's Hospital of Los Angeles and the University of Southern California Keck School of Medicine, Los Angeles, CA 90027, USA. mkearns@chla.usc.edu
Fischer-Lougheed
Jacqueline
J
Shulkin
Irina
I
Kleihauer
Annette
A
Mitsuhashi
Noboru
N
Kohn
Donald B
DB
Weinberg
Kenneth
K
D'Apice
Anthony J F
AJ
Starnes
Vaughn A
VA
Cramer
Donald V
DV
D000818:Animals; D000906:Antibodies / Q000032:analysis; D000910:Antibodies, Heterophile / Q000032:analysis; D001402:B-Lymphocytes / Q000276:immunology; D001853:Bone Marrow / Q000378:metabolism; D016026:Bone Marrow Transplantation; D004187:Disaccharides / Q000378:metabolism; D005700:Galactosyltransferases / Q000235:genetics*; D005822:Genetic Vectors; D006084:Graft Rejection; D006085:Graft Survival; D016027:Heart Transplantation / Q000276:immunology*; D016086:Lentivirus / Q000235:genetics*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013154:Spleen / Q000276:immunology / Q000473:pathology; D013552:Swine; D014161:Transduction, Genetic; D018183:Transplantation Chimera / Q000276:immunology; D023001:Transplantation Tolerance; D016042:Transplantation, Heterotopic
D000906:Antibodies; D000910:Antibodies, Heterophile; D004187:Disaccharides; D011993:Recombinant Fusion Proteins; C055075:galactosyl-(1-3)galactose; D005700:Galactosyltransferases; C487611:alpha 1,3 galactosyltransferase, mouse