Targeted gene delivery to CD117‐expressing cells in vivo with lentiviral vectors co‐displaying stem cell factor and a fusogenic molecule

Abstract

The development of a lentiviral system to deliver genes to specific cell types could improve the safety and the efficacy of gene delivery. Previously, we have developed an efficient method to target lentivectors to specific cells via an antibody-antigen interaction in vitro and in vivo. We report herein a targeted lentivector that harnesses the natural ligand-receptor recognition mechanism for targeted modification of c-KIT receptor-expressing cells. For targeting, we incorporate membrane-bound human stem cell factor (hSCF), and for fusion, a Sindbis virusderived fusogenic molecule (FM) onto the lentiviral surface. These engineered vectors can recognize cells expressing surface CD117, resulting in efficient targeted transduction of cells in a SCF-receptor dependent manner in vitro, and in vivo in xenografted mouse models. This study expands the ability of targeting lentivectors beyond antibody targets to include cell-specific surface receptors. Development of a high titer lentivector to receptor-specific cells is an attractive approach to restrict gene expression and could potentially ensure therapeutic effects in the desired cells while limiting side effects caused by gene expression in non-target cells.

A novel lentiviral vector targets gene transfer into human hematopoietic stem cells in marrow from patients with bone marrow failure syndrome and in vivo in humanized mice

“…Froelich et al incorporated both membrane-bound-SCF and a Sindbis-glycoprotein for vector-cell fusion at the surface of an LV, but the efficiency of these vectors for hCD34 ϩ -cell transduction was not tested. 31 Another group used a Sindbis glycoprotein in which they incorporated the ZZ-domain of protein A conjugated with anti-CD34 Ab, which transduced hCD34 ϩ cells. However, it is difficult to predict how these LVs will behave in vivo.…”

Immunization delivered by lentiviral vectors for cancer and infectious diseases

“…The Sindbis virus fusogen molecule was further mutated to elevate the fusion functions in a pH‐dependent manner (105). This system was also useful for targeting monospecific Ig‐expressing B cells (106), CD3 + T cells (107), and CD117‐expressing HSCs (108). To better understand the interactions between the binding and fusion processes of the LVs and the target cells, the GFP‐Vpr protein was incorporated into the LVs to label and track the vector particles by confocal microscopy.…”

Alphavirus Vectors for Therapy of Neurological Disorders

“…In this context, lentiviral vectors were targeted to stem cells by incorporation of the membrane-bound human stem cell factor (hSCF) and the Sindbis virus-derived fusogenic molecule (FM) [45]. This approach resulted in efficient targeting of cells expressing CD117, a type III cell surface transmembrane tyrosine kinase receptor, which naturally binds hSCF.…”