Targeted gene transfer to lymphocytes using murine leukaemia virus vectors pseudotyped with spleen necrosis virus envelope proteins

Retroviral Vectors

“…Since then, successful extension of the host range of SNV vectors to human cells has been described by using four different scFv molecules. This is an important improvement of the system making the in vivo application of this vector type in humans possible [46]. Other scFvs molecules were directed either against the human CD34 antigen, the transferrin receptor, or the Her2neu antigen (overexpressed in many human breast cancer cases), all of which mediated transduction of human cells, in part with considerable efficiency (2×10 5 efu/ml) [44].…”

Surface Modification of Retroviral Vectors for Gene Therapy

“…A range of different strategies have been tested to change the infection tropism including the use of glycoproteins from heterologous viral species (pseudotyping) or chimeric envelope glycoproteins (Env fusion proteins) as well as bridging molecules (adaptors) (Waehler et al 2007). The application of pseudotyping for transduction targeting (Croyle et al 2004;Engelstadter et al 2001;Miller et al 1991) is limited by the range of available glycoproteins with useful infection tropisms. A more versatile strategy is the use of chimeric envelope proteins in which parts of the protein responsible for receptor binding are replaced with peptides (Gollan and Green 2002), ligands (Cosset et al 1995;Kasahara et al 1994) or singlechain antibodies (Anliker et al 2010;Somia et al 1995) conferring binding to the desired receptors for viral entry.…”

Envelope proteins of spleen necrosis virus form infectious human immunodeficiency virus type 1 pseudotype vector particles, but fail to incorporate upon substitution of the cytoplasmic domain with that of Gibbon ape leukemia virus

“…It is hypothesized that the scFv anchors the vector particle to the cell surface and thereby enables interaction of the wt SNV Env protein with a mutated human receptor -otherwise not facilitating cell entry and the consequent membrane fusion (Jiang et al, 1998). This strategy of cell targeting has to date only been used for the generation of onco-retroviral particles (Jiang et al, 1998;Engelstadter et al, 2000Engelstadter et al, , 2001. To assess the feasibility of establishing stable HIV-1-derived packaging cells, we attempted to generate infectious HIV-1 vector particles pseudotyped only with the wt Env proteins of SNV as a first step for the future production of lentiviral cell targeting vectors.…”

“…A known determinant for fusogenicity is the socalled R peptide within the C-terminal cytoplasmic domain (C-tail) of the TM protein. The R peptide must be cleaved by a viral protease during virion maturation to mediate virus cell entry (Green et al, 1981;Henderson et al, 1984;Engelstadter et al, 2001;Bobkova et al, 2002). However, the R peptide, or more specifically the protease cleavage site of the C-tail of GaLV Env, has been shown to inhibit incorporation of GaLV TM proteins into HIV-1-derived 3These authors contributed equally to this work.…”