ENCAPSIDATION OF A RECOMBINANT LUIII PARVOVIRUS GENOME BY H1 VIRUS AND THE FIBROTROPIC OR LYMPHOTROPIC STRAINS OF MINUTE VIRUS OF MICE

We previously constructed a recombinant LuIII parvovirus genome lacking viral coding sequences and used it to generate luciferase-transducing virions, by cotransfection of cells with a helper plasmid expressing LuIII viral proteins. Here, we describe similar cotransfections using alternative, replication-defective helpers encoding the non-structural and capsid proteins of parvovirus H1, or of either the fibrotropic or lymphotropic parvovirus strain of minute virus of mice [MVM(p) or MVM(i)]. Each cotransfection generated transducing virus which directed luciferase expression after infection of HeLa cells. The transducing activity of virus produced using either LuIII or H1 helper plasmids could be specifically neutralized by antiserum raised against the corresponding infectious virus. When the recombinant LuIII parvovirus was pseudotyped with MVM(p) or MVM(i), the resulting virions efficiently expressed luciferase after infection in human or murine cells known to be permissive for both MVM strains. The MVM(p) pseudotyped virus also expressed this reporter efficiently when infected into the murine A9 fibroblast line. In contrast, the recombinant virus generated with an MVM(i) helper gave luciferase expression that was barely detectable after infection of A9 cells which are highly restrictive for MVM(i) productive infection. These results support the notion that the allotropic determinant of these MVM strains functions through their capsid proteins. Pseudotyping of recombinant parvovirus genomes should be useful in controlling their host range as vectors, and in studying mechanisms influencing the permissiveness of parvovirus infections.