Parvovirus capsids

Abstract

The present invention relates to a method of producing non-infections parvovirus capsids and to diagnostic assays and vaccines utilizing same. The invention further relates to recombinant baculoviruses encoding parvovirus structural proteins and host cells infected therewith. The invention also relates to a method of packaging and delivering genetic information utilizing the noninfectious capsids.

What is claimed is:  
     
         1 . A method of producing parvovirus capsids comprising the steps of: 
 i) introducing into a host cell a recombinant DNA molecule comprising: 
 a) an expression vector, and  
 b) a DNA sequence encoding the structural proteins of a parvovirus, with the proviso that genes encoding nonstructural parvovirus proteins are not included in the DNA sequence;  
   ii) culturing the cells under conditions such that said structural proteins are produced and self assemble to form the capsids; and    iii) isolating the capsids.    
     
     
         2 . The method according to  claim 1  wherein said parvovirus is B19.  
     
     
         3 . The method according to  claim 1  wherein said host cell is a mammalian cell.  
     
     
         4 . The method according to  claim 3  wherein said mammalian cell is a dehydrofolate reductase-deficient Chinese hamster ovary cell.  
     
     
         5 . A parvovirus antigen consisting essentially of a parvovirus capsid.  
     
     
         6 . The parvovirus antigen according to  claim 5  wherein said parvovirus capsid has a minor structural protein to major structural protein ratio higher than the ration of the naturally occurring capsid.  
     
     
         7 . The parvovirus antigen according to  claim 6  wherein said major structural protein to minor structural protein ratio is at least 3:1.  
     
     
         8 . The parvovirus antigen according to  claim 7  wherein said ratio is between 10:1 to 20:1.  
     
     
         9 . The parvovirus antigen according to  claim 5  wherein said parvovirus is B19.  
     
     
         10 . A parvovirus antigen consisting essentially of a parvovirus capsid of major structural proteins free of minor structural proteins.  
     
     
         11 . A diagnostic assay for parvovirus infection comprising: 
 i) contacting a sample from a patient suspected of being infected with parvovirus with said parvovirus antigen according to  claim 5  or  claim 10 , and    ii) detecting the formation of a complex between anti-parvovirus antibodies present in said sample and said parvovirus antigen.    
     
     
         12 . The assay according to  claim 11  wherein said parvovirus is B19.  
     
     
         13 . The assay according to  claim 11  wherein said sample is a serum sample.  
     
     
         14 . An anti-parvovirus vaccine comprising said parvovirus antigen according to  claim 5  and a pharmaceutically acceptable carrier.  
     
     
         15 . The vaccine according to  claim 14  wherein said parvovirus is B19.  
     
     
         16 . A method of packaging and transferring genetic information comprising: 
 i) encapsidating said genetic information in said parvovirus capsid according to  claim 5;  and    ii) introducing said encapsidated information into a host cell.    
     
     
         17 . The method according to  claim 16  wherein said parvovirus is B19.  
     
     
         18 . A diagnostic kit comprising: 
 i) said parvovirus antigen according to  claim 5  or  claim 10;  and    ii) ancillary reagents.    
     
     
         19 . The diagnostic kit according to  claim 18  wherein said parvovirus is B19.  
     
     
         20 . The diagnostic kit according to  claim 18  further comprising a signal-producing system.  
     
     
         21 . A recombinant baculovirus comprising a DNA segment encoding a minor structural protein of a parvovirus.  
     
     
         22 . A recombinant baculovirus comprising a DNA segment encoding a major structural protein of a parvovirus.  
     
     
         23 . A recombinant baculovirus according to  claim 21  or  claim 22  wherein said baculovirus is  Autographa california  nuclear polyhedrosis virus.  
     
     
         24 . A recombinant baculovirus according to  claim 21  or  claim 22  wherein said parvovirus is B19.  
     
     
         25 . A method of producing parvovirus capsids comprising the steps of: 
 i) infecting an insect cell with said recombinant baculovirus according to  claim 22;     ii) culturing said cells under conditions such that said major structural proteins are produced and self assemble to form the capsids; and    iii) isolating the capsids.    
     
     
         26 . The method according to  claim 25  wherein said insect is  Spodoptera frugiperda.    
     
     
         27 . A method of producing parvovirus capsids comprising the steps of: 
 i) infecting an insect cell with (a) a first recombinant baculovirus comprising a DNA segment encoding a minor structural parvovirus protein and (b) a second recombinant baculovirus comprising a DNA segment encoding a major structural parvovirus protein;    ii) culturing said cells under conditions such that said minor structural protein and said major structural protein are produced and self assemble to form the capsids; and    iii) isolating the capsids.    
     
     
         28 . The method according to  claim 27  wherein said insect is  Spodoptera frugiperda.    
     
     
         29 . A method of producing a protein presenting capsid comprising the steps of: 
 i) coinfecting an insect cell with (a) a first recombinant baculovirus encoding a major structural parvovirus protein and (b) a second recombinant baculovirus encoding the nonunique region of a minor structural parvovirus protein and a nonparvovirus protein;    ii) culturing said cells under conditions such that said expressed proteins self assemble to form the capsids; and    iii) isolating the capsids.    
     
     
         30 . The method according to  claim 29  wherein said nonparvovirus protein is an antigenic epitope, ligand or enzyme.  
     
     
         31 . A protein presenting capsid comprising a major structural parvovirus protein and a nonunique region of a minor structural parvovirus protein joined to a nonparvovirus protein.