X-linked severe combined immunodeficiency (SCID) is one of a number of diseases characterized by profound defects in both T-cell and B-cell immunity. The only treatment for the X-linked form of SCID is bone marrow transplantation, however, the use of somatic cell gene transfer has long been proposed as treatment for SCID and other inherited hematopoietic diseases. A naturally occurring animal model for human X-linked SCID exists in a breeding colony of dogs, which have the same clinical, genetic, immunologic, and pathologic features as human X-linked SCID patients. In humans, this disease is caused by mutations in the gene for the gamma chain of the interleukin-2 receptor (IL2RG). We have recently demonstrated that the canine disease is also caused by a mutation in the IL2RG gene, and thus represents a true homologue of the human disease. The goals of the proposed studies are to use the XSCID dog model to investigate approaches to somatic cell gene therapy for immunodeficiencies. In order to do so, the numbers of affected animals available for study will be increased by breeding affected animals that have been rescued by bone marrow transplantation and assays for canine IL2RG chain function, which can be used to characterize different gene transfer vectors, will be developed. Gene transfer vector viruses containing the canine IL2RG cDNA will be constructed and introduced into X-linked SCID bone marrow and peripheral blood cells, with or without enrichment for hematopoietic stem cells by positive selection with antibodies specific for canine CD34. Transduced cells will be introduced into affected puppies and the ability of these cells to reconstitute the animals' immune systems will be carefully monitored, using sensitive techniques. The canine XSCID model is ideal for performing the controlled experiments, most of which are not possible in human patients, necessary to evaluate the efficacy of gene therapy approaches for the treatment of immunodeficiencies. Since the precise control mechanisms and range of expression of the IL2RG gene remain to be elucidated, as do the effects of excessive or inappropriate expression over the lifetime of an animal, the dog is particularly valuable as a long-lived and relatively large animal, allowing repeated sampling and long-term monitoring of immunologic functions.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI033177-05
Application #
2517212
Study Section
Special Emphasis Panel (ZRG5-IMB (02))
Project Start
1993-09-30
Project End
1999-08-31
Budget Start
1997-09-01
Budget End
1998-08-31
Support Year
5
Fiscal Year
1997
Total Cost
Indirect Cost
Name
University of Pennsylvania
Department
Other Clinical Sciences
Type
Schools of Veterinary Medicine
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
Suter, Steven E; Gouthro, Terry A; O'Malley, Thomas et al. (2007) Marking of peripheral T-lymphocytes by retroviral transduction and transplantation of CD34+ cells in a canine X-linked severe combined immunodeficiency model. Vet Immunol Immunopathol 117:183-96
Suter, S E; Gouthro, T A; McSweeney, P A et al. (2006) Optimized transduction of canine paediatric CD34(+) cells using an MSCV-based bicistronic vector. Vet Res Commun 30:881-901
Suter, Steven E; Gouthro, Terry A; McSweeney, Peter A et al. (2004) Isolation and characterization of pediatric canine bone marrow CD34+ cells. Vet Immunol Immunopathol 101:31-47
Licht, Thomas; Haskins, Mark; Henthorn, Paula et al. (2002) Drug selection with paclitaxel restores expression of linked IL-2 receptor gamma -chain and multidrug resistance (MDR1) transgenes in canine bone marrow. Proc Natl Acad Sci U S A 99:3123-8
Whitwam, T; Haskins, M E; Henthorn, P S et al. (1998) Retroviral marking of canine bone marrow: long-term, high-level expression of human interleukin-2 receptor common gamma chain in canine lymphocytes. Blood 92:1565-75
Bucci, J G; English, R V; Jordan, H L et al. (1998) Mucosally transmitted feline immunodeficiency virus induces a CD8+ antiviral response that correlates with reduction of cell-associated virus. J Infect Dis 177:18-25
Felsburg, P J; Somberg, R L; Hartnett, B J et al. (1997) Full immunologic reconstitution following nonconditioned bone marrow transplantation for canine X-linked severe combined immunodeficiency. Blood 90:3214-21
Somberg, R L; Pullen, R P; Casal, M L et al. (1995) A single nucleotide insertion in the canine interleukin-2 receptor gamma chain results in X-linked severe combined immunodeficiency disease. Vet Immunol Immunopathol 47:203-13
Henthorn, P S; Somberg, R L; Fimiani, V M et al. (1994) IL-2R gamma gene microdeletion demonstrates that canine X-linked severe combined immunodeficiency is a homologue of the human disease. Genomics 23:69-74