A high capacity Alphavirus heterologous gene delivery system

A novel replication competent Sindbis virus based gene delivery vector has been developed for the introduction of genetic cargo into cell lines in vitro and potentially, animal models in vivo. This delivery system expands the previous uses of Sindbis virus as a gene delivery system in that no replicons are required and the resulting cargo containing virus particles are infectious. The heterologous vector is based on a morphological mutant in C, Ser180/Gly183 which produces larger than the normal size T=4 virus particles of 70 nm in size. This mutant produced particles up to 205 nm in size equal to a triangulation number of 36. It was postulated that because the Ser180/Gly183 mutant was capable of assembling such large particles, that increasing the size of the RNA genome incorporated into this mutant capsid protein would favor the assembly of larger than T=4 wild type sized virions. The first generation prototype larger vehicle, described here, carries a approximately 18 kb cDNA insert, however it is conceivable that RNA as large as 32 kb could be transcribed and packaged. The large variant produces a high virus titer of approximately 10(9) pfu/ml from either mammalian or insect cells in culture. Multiple passages of the virus show no loss of the inserted genetic material.