X-linked severe combined immune deficiency (X-SCID) is the most common form of SCID caused by mutations in the gene for the common gammac cytokine receptor chain. Human and canine X-SCID are marked by a block in thymopoiesis, peripheral T and NK lymphopenia, and presence of phenotypic B cells with defective antibody responses. Murine knockouts for gammac differ from humans and dogs in that the affected mice have both T and B lymphopenia. Bone marrow transplant (BMT), by introducing normal hematopoietic stem cells (HSC), can be used to cure patients with X-SCID. Because of the immunoincompetence of the recipients and the selective advantage to the normal HSC, histocompatible BMT can generally be performed without prior cytoablative chemo- or radiotherapy. Most patients do not have histocompatible donors and receive alternate therapy with histoincompatible BMT, which is less successful. Transplantation of autologous HSC genetically modified to express the defective gene (stem cell gene therapy) is an alternative approach which may ultimately prove to be superior to histoincompatible BMT. The present techniques for transducing HSC with retroviral vectors are inefficient and result in low numbers of transduced HSC for transplantation. Our clinical trial of gene therapy for ADA deficient SCID has demonstrated that retrovirally transduced HSC can engraft without cytoablation, generating transduced T, B, and myeloid cells expressing normal levels of ADA. The frequency of vector-positive cells T cells has risen because of the selective advantage conferred to the transduced cells by the expression of ADA. Gene therapy of canine X- SCID is an ideal large animal pre-clinical model, in that canine X-SCID is phenotypically identical to that of humans, and it is likely that the same vectors and reagents to be used in a clinical trial could be tested in the dog model. As in ADA deficiency, there is an expected selective advantage to T cell progenitors expressing the normal gene product, which may allow restoration of immune function in spite of the relatively low levels of HSC transduction. The studies will analyze transduction, engraftment, and functional correction of the immune system in X-SCID dogs receiving autologous CD34+ marrow cells from X- SCID dogs after transduction with retroviral vectors containing the human gammac cDNA. The studies will use a combination of biochemical and immunologic analyses, in vitro culture of transduced hematopoietic progenitors, and in vivo transplantation of transduced HSC into X-SCID dogs to test gene therapy. Modifications of the vector LTR will be tested for the ability to give activation-independent expression and to prevent vector silencing. We will test whether the administration of the thymopoietic cytokine IL-7 after gene therapy will accelerate the usually slow development of functional immunity from HSC.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI043745-02
Application #
2887846
Study Section
Special Emphasis Panel (ZHL1-CSR-B (01))
Program Officer
Ash-Shaheed, Belinda
Project Start
1998-05-01
Project End
2003-04-30
Budget Start
1999-05-01
Budget End
2000-04-30
Support Year
2
Fiscal Year
1999
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
Felsburg, Peter J; De Ravin, Suk See; Malech, Harry L et al. (2015) Gene therapy studies in a canine model of X-linked severe combined immunodeficiency. Hum Gene Ther Clin Dev 26:50-6
Luff, Jennifer A; Yuan, Hang; Kennedy, Douglas et al. (2014) Keratinocyte antiviral response to Poly(dA:dT) stimulation and papillomavirus infection in a canine model of X-linked severe combined immunodeficiency. PLoS One 9:e102033
Kennedy, Douglas R; Hartnett, Brian J; Kennedy, Jeffrey S et al. (2011) Ex vivo ?-retroviral gene therapy of dogs with X-linked severe combined immunodeficiency and the development of a thymic T cell lymphoma. Vet Immunol Immunopathol 142:36-48
Kennedy, Douglas R; McLellan, Kyle; Moore, Peter F et al. (2009) Effect of ex vivo culture of CD34+ bone marrow cells on immune reconstitution of XSCID dogs following allogeneic bone marrow transplantation. Biol Blood Marrow Transplant 15:662-70
Vernau, William; Hartnett, Brian J; Kennedy, Douglas R et al. (2007) T cell repertoire development in XSCID dogs following nonconditioned allogeneic bone marrow transplantation. Biol Blood Marrow Transplant 13:1005-15
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
Goldschmidt, Michael H; Kennedy, Jeffrey S; Kennedy, Douglas R et al. (2006) Severe papillomavirus infection progressing to metastatic squamous cell carcinoma in bone marrow-transplanted X-linked SCID dogs. J Virol 80:6621-8
Swerdlow, Mathew P; Kennedy, Douglas R; Kennedy, Jeffrey S et al. (2006) Expression and function of TLR2, TLR4, and Nod2 in primary canine colonic epithelial cells. Vet Immunol Immunopathol 114:313-9
Ting-De Ravin, Suk See; Kennedy, Douglas R; Naumann, Nora et al. (2006) Correction of canine X-linked severe combined immunodeficiency by in vivo retroviral gene therapy. Blood 107:3091-7
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

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