Receptor-specific targeting mediated by the coexpression of a targeted murine leukemia virus envelope protein and a binding-defective influenza hemagglutinin protein.
The entry of retroviral vectors into cells requires two events: binding to a cell surface receptor and the subsequent fusion of viral and cellular membranes. The host range of a vector is therefore determined largely by the receptor specificity of the fusion protein contained in the outer viral envelope. Previous attempts to generate targeted retroviral vectors have included the addition of targeting ligands to the murine leukemia virus envelope protein (MuLV Env). Although such proteins frequently display modified cell-binding characteristics, the interaction with the targeted receptors fails to trigger virus-cell fusion. Here, we report the use of a binding-defective but fusion-competent hemagglutinin (HA) protein to complement the fusion defect in a chimeric MuLV Env targeted to the Flt-3 receptor. Retroviral vectors containing both proteins showed enhanced transduction of cells expressing Flt-3, which was abrogated by preincubating the target cells with soluble Flt-3 ligand. Furthermore, the fusion function of HA was absolutely required. These data demonstrate that it is possible to separate the binding and fusion events of retroviral entry, using two separate proteins, and suggest that varying the binding protein component in this scheme may allow a general strategy for targeting retroviral vectors.
Gene Therapy Laboratories, Norris Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, CA 90033, USA.
A H
AH
Lin
N
N
Kasahara
W
W
Wu
R
R
Stripecke
C L
CL
Empig
W F
WF
Anderson
P M
PM
Cannon
D016475:3T3 Cells; D000818:Animals; D001665:Binding Sites / Q000235:genetics; D002460:Cell Line; D015686:Gene Products, env / Q000235:genetics*; D018390:Gene Targeting; D005822:Genetic Vectors; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics*; D006801:Humans; D009052:Leukemia Virus, Murine / Q000235:genetics*; D008561:Membrane Fusion; D051379:Mice; D009154:Mutation; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism; D011991:Receptors, Virus / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000235:genetics; D012190:Retroviridae / Q000235:genetics*; D014759:Viral Envelope Proteins / Q000737:chemistry*; D051941:fms-Like Tyrosine Kinase 3
D015686:Gene Products, env; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D011518:Proto-Oncogene Proteins; D011991:Receptors, Virus; D011993:Recombinant Fusion Proteins; D014759:Viral Envelope Proteins; C497970:FLT3 protein, human; C497971:Flt3 protein, mouse; D020794:Receptor Protein-Tyrosine Kinases; D051941:fms-Like Tyrosine Kinase 3