Viral vector nanocapsule for targeting gene therapy and its preparation

Abstract

The invention provides novel methods, materials and systems that can be used to generate viral vectors having altered tissue and cell targeting abilities. In illustrative embodiments of the invention, the specificity of lentiviral vectors was modulated by a thin polymer shell that synthesized and coupled to the viral envelope in situ. The polymer shell can confers such vectors with new targeting ability via agents such as cyclic RGD (cRGD) peptides that are coupled to the polymer shell. These polymer encapsulated viral vectors exhibit a number of highly desirable characteristics including a higher thermal stability, resistance to serum inactivation in vivo, and an ability to infect dividing and non-dividing cells with high efficiencies.

What is claimed is: 
     
         1 . A method of preparing an encapsulated viral vector comprising:
 reacting a polymerizable molecular anchor with a viral vector so as to generate a polymerizable group;   reacting the polymerizable group to a plurality of monomers to form a polymer shell that encapsulates the viral vector;   crosslinking the polymer shell with a degradable cross-linking agent; and   coupling a targeting agent to the polymer shell.   
     
     
         2 . The method of  claim 1 , wherein the polymerizable molecular anchor is conjugated to a lysine in a protein expressed by the viral vector. 
     
     
         3 . The method of  claim 1 , wherein reacting the polymerizable group to a plurality of monomers to form a polymer shell over a surface of the viral vector occurs in-situ. 
     
     
         4 . The method of  claim 1 , wherein the polymer shell degrades in an acidic environment, thereby releasing the viral vector from the polymer shell. 
     
     
         5 . The method of  claim 1 , wherein at least one viral protein is a Vesicular stomatitis Indiana virus G protein (VSV-G), the polymerizable molecular anchor is N-acryloxysuccinimide (NAS), the monomer is acrylamide or the degradable cross-linker is glycidyl methacrylate (GMA). 
     
     
         6 . The method of  claim 5 , wherein the m/m ratio of NAS to viral vector is 2×10 4  and the w/w ratio of monomer to virus is 125. 
     
     
         7 . The method of  claim 1 , wherein the targeting agent is an antibody, a ligand or a growth factor. 
     
     
         8 . The method of  claim 1 , wherein the targeting agent binds a tumor cell, a neuronal cell or a peripheral blood mononuclear cell. 
     
     
         9 . The method of  claim 1 , wherein the targeting agent is a cyclic arginine-glycine-aspartic acid (cRGD), said cRGB having an affinity to an αvβ 3  integrin on a tumor cell. 
     
     
         10 . A method of modulating the cellular specificity of a viral vector comprising:
 selecting a viral vector having a first specificity for a target tissue or cellular lineage;   encapsulating the viral vector in a polymeric shell, wherein the polymeric shell comprises:
 a plurality of polymers cross-linked by a degradable crosslinking agent so as to form a polymer shell that degrades in vivo; and 
 a targeting agent attached to the cross-linked degradable polymer shell, wherein the targeting agent is selected to have a second specificity for a target tissue or cellular lineage, and the second specificity is different from the first specificity; 
   so that the cellular specificity of the viral vector is modulated.   
     
     
         11 . The method of  claim 10 , wherein the targeting agent comprises a polypeptide. 
     
     
         12 . The method of  claim 10 , wherein the targeting agent comprises a cyclic arginine-glycine-aspartic acid (cRGD). 
     
     
         13 . The method of  claim 10 , wherein the viral vector is selected from the group consisting of: retroviral vectors, adenoviral vectors, lentiviral vectors, herpes simplex viral vectors, vaccinia, pox viral vectors, Sindbis viral vectors and adeno-associated viral vectors. 
     
     
         14 . The method of  claim 1 , wherein the polymer shell is formed to shield a native binding ability of the viral vector. 
     
     
         15 . The method of  claim 1 , wherein the polymer shell is formed to degrade at a pH below 6.0, thereby releasing the viral vector from the polymer shell. 
     
     
         16 . The method of  claim 1 , wherein a lysine residue on the viral vector is coupled to the polymer shell. 
     
     
         17 . The method of  claim 10 , wherein the polymer shell is formed to shield a native binding ability of the viral vector. 
     
     
         18 . The method of  claim 10 , wherein the polymer shell is formed to degrade at a pH below 6.0, thereby releasing the viral vector from the polymer shell. 
     
     
         19 . The method of  claim 10 , wherein a lysine residue on the viral vector is coupled to the polymer shell. 
     
     
         20 . The method of  claim 10 , wherein the targeting agent binds a tumor cell, a neuronal cell or a peripheral blood mononuclear cell.