Abstract

Immunologic reactions against gene therapy products may prove to be a frequent problem in clinical gene therapy protocols. Enhanced green fluorescence protein (EGFP) is commonly used as a marker in gene transfer protocols, and immune responses against EGFP-expressing cells have been documented. The present study was designed to investigate the effect of a pharmacologic, nonmyeloablative, conditioning regimen on the development of EGFP(+) donor/recipient mixed bone marrow chimerism and ensuing tolerance to EGFP-expressing transplants. To this end, C57BL/6J (136) mice were treated with soluble formulations of either busulfan (Busulfex) or the closely related compound treosulfan, followed by transplantation of bone marrow cells from EGFP-transgenic (B6-EGFR.Tg) donor mice. Such conditioning regimens resulted in long-term persistence of donor EGFP(+) cells among various hematopoietic lineages from blood, bone marrow, and thymus. Stable hematopoietic chimeras transplanted at 10 to 17 weeks after bone marrow transplantation (BMT) with B6-EGFP.Tg skin grafts all accepted their transplants, whereas non-EGFP chimeric B6 control animals were able to mount rejection of the EGFP(+) B6 skin grafts. Control third-party grafts from major histocompatibility complex (MHC)-mismatched mice were rejected within 20 days, indicating that acceptance of EGFP-expressing skin grafts was the result of specific immune tolerance induction by the transplantation of EGFP-transgenic bone marrow. Long-term tolerance to EGFP in chimeric recipients was confirmed by the absence of anti-EGFP-reactive T cells and antibodies. These results broaden the therapeutic potential for using hematopoietic molecular chimerism in nonmyeloablated recipients as a means of preventing rejection of genetically modified cells. (C) 2003 by The American Society of Hematology

Published in

Blood
2003, Volume: 101, number: 11, pages: 4305-4312
Publisher: AMER SOC HEMATOLOGY

SLU Authors

• Andersson, Göran

  • Department of Animal Biosciences, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Animal and Dairy Science
Veterinary Science


Publication identifier

DOI: https://doi.org/10.1182/blood-2002-06-1649

Permanent link to this page (URI)

https://res.slu.se/id/publ/714