1. ¹Institut Paoli-Calmettes, Centre de Thérapie Cellulaire et Génique, Centre Régional de Lutte Contre le Cancer, Marseille, France
2. ²Centre d'Investigations Cliniques en Biothérapie, CIC-B 510 & INSERM UMR599, Centre de Recherche en Cancérologie de Marseille (CRCM), Marseille, France
3. ³Université de la Méditerranée, Marseille, France
4. ⁴Assistance Publique des Hôpitaux de Marseille, Service d'Hématologie Pédiatrique, Marseille, France
5. ⁵Laboratoire d'Immunologie des Tumeurs, INSERM UMR599 Centre de Recherche en Cancérologie de Marseille (CRCM), Marseille, France

Correspondence: Dr C Tonnelle, Centre de Thérapie Cellulaire et Génique, Institut Paoli-Calmettes, 232 Bd Sainte Marguerite, Marseille Cedex 9 13273, France. E-mail: tonnellec@marseille.fnclcc.fr

Received 19 September 2007; Revised 21 December 2007; Accepted 21 January 2008; Published online 6 March 2008.

Abstract

Further development of haematopoietic stem cell (HSC) gene therapy will depend on enhancement of gene transfer safety: ad hoc improvement of vector design relating to each particular disease is thus a crucial issue for HSC gene therapy. We modified a previously described lentiviral vector by adding the Emar B-specific enhancer to a human CD19 promoter-derived sequence (Mol Ther 2004;10:45–56). We thus significantly improved the level of expression of the green fluorescent protein (GFP) reporter gene while retaining the specificity of expression in B-cell progeny of transduced human CD34+ progenitor cells obtained from cord blood or adult bone marrow. Indeed, GFP was strongly expressed from early medullary pro-B cells to splenic mature B cells whereas transgene expression remained low in transduced immature progenitors as in myeloid and T-lymphoid progeny retrieved from xenografted NOD/SCID/c^null mice. Using this lentiviral vector, we further demonstrated the possibility to express a functional human BTK protein in long-term human CD34+ cell B-lymphoid progeny. This newly designed lentiviral vector fulfils one of the pre-requisites for the development of efficient and safe gene therapy for X-linked agammaglobulinaemia, the most common primary humoral immunodeficiency disorder.