http://repub.eur.nl/res/aut/14877/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/30754/ 2011-10-01T00:00:00Z Clinical trials have demonstrated the potential of ex vivo hematopoietic stem cell gene therapy to treat X-linked severe combined immunodeficiency (SCID-X1) using γ-retroviral vectors, leading to immune system functionality in the majority of treated patients without pretransplant conditioning. The success was tempered by insertional oncogenesis in a proportion of the patients. To reduce the genotoxicity risk, a self-inactivating (SIN) lentiviral vector (LV) with improved expression of a codon optimized human interleukin-2 receptor γ gene (IL2RG) cDNA (coγc), regulated by its 1.1 kb promoter region (γcPr), was compared in efficacy to the viral spleen focus forming virus (SF) and the cellular phosphoglycerate kinase (PGK) promoters. Pretransplant conditioning of Il2rg-/-mice resulted in long-term reconstitution of T and B lymphocytes, normalized natural antibody titers, humoral immune responses, ConA/IL-2 stimulated spleen cell proliferation, and polyclonal T-cell receptor gene rearrangements with a clear integration preference of the SF vector for proto-oncogenes, contrary to the PGK and γcPr vectors. We conclude that SIN lentiviral gene therapy using coγc driven by the γcPr or PGK promoter corrects the SCID phenotype, potentially with an improved safety profile, and that low-dose conditioning proved essential for immune competence, allowing for a reduced threshold of cell numbers required. http://repub.eur.nl/res/pub/26260/ 2011-09-01T00:00:00Z Severe combined immunodeficiency (SCID) patients with an inactivating mutation in recombination activation gene 1 (RAG1) lack B and T cells due to the inability to rearrange immunoglobulin (Ig) and T-cell receptor (TCR) genes. Gene therapy is a valid treatment option for RAG-SCID patients, especially for patients lacking a suitable bone marrow donor, but developing such therapy has proven challenging. As a preclinical model for RAG-SCID, we used Rag1-/-mice and lentiviral self-inactivating (SIN) vectors harboring different internal elements to deliver native or codon-optimized human RAG1 sequences. Treatment resulted in the appearance of B and T cells in peripheral blood and developing B and T cells were detected in central lymphoid organs. Serum Ig levels and Ig and TCR VΒ gene segment usage was comparable to wild-type (WT) controls, indicating that RAG-mediated rearrangement took place. Remarkably, relatively low frequencies of B cells produced WT levels of serum immunoglobulins. Upon stimulation of the TCR, corrected spleen cells proliferated and produced cytokines. In vivo challenge resulted in production of antigen-specific antibodies. No leukemia development as consequence of insertional mutagenesis was observed. The functional reconstitution of the B-as well as the T-cell compartment provides proof-of-principle for therapeutic RAG1 gene transfer in Rag1-/-mice using lentiviral SIN vectors. http://repub.eur.nl/res/pub/12818/ 2002-01-01T00:00:00Z As the year 2000 approached, so too did the years 5760, 2544, and 1420, according to the Jewish, Buddhist, and Moslem dating systems, respectively. Still, the coming of the year 2000 held meaning for most Western societies, serving as an opportunity for broader speculation about the new millennium and the 21st century. In the field of management, cycles of boom and bust in Asia had called into question new ways of organizing hailed in the 1980s, and questions and concerns mounted about inadequacies of 20th century views of business firms. Opinions were astonishingly diverse and often contradictory, but the central theme was change--dramatic change--and the idea that, to cope with it, managers ought to strategize anew and shape and reshape their firms.