Modified EC7 Cells Having Low Toxicity to Viral Production Payloads

Abstract

Recombinant cells and methods therefor are contemplated that allow for rapid and high titer production of recombinant viruses, and especially replication deficient Ad5 virus. In some preferred aspects, the host cell is modified to produce an inhibitor that reduces or eliminates the expression of a therapeutic protein encoded in the virus, while in other aspects, the virus includes a gene that directly or indirectly reduces or eliminates the expression of a therapeutic protein encoded in the virus. Most preferably, shRNA encoded by the host cell will reduce or suppress expression of a payload gene encoded in the recombinant virus.

What is claimed is: 
     
         1 . A recombinant virus comprising a sequence encoding an mRNA for a recombinant payload and having a 3′-UTR segment that has at least one binding site for an shRNA that is absent in a patient cell to which the virus is administered. 
     
     
         2 . The recombinant virus of  claim 1  wherein the virus is an adenovirus. 
     
     
         3 . The recombinant virus of  claim 1  wherein the payload is at least one of a cytokine, a chimeric protein, a tumor associated antigen, and a neoepitope. 
     
     
         4 . The recombinant virus of  claim 1  wherein the binding site is for a luciferase shRNA, lacZ shRNA, or beta-lactamase shRNA. 
     
     
         5 . The recombinant virus of  claim 1  having at least a second binding site for a second shRNA that is absent in the patient cell to which the virus is administered. 
     
     
         6 . A genetically engineered cell that comprises a recombinant nucleic acid encoding a shRNA that reduces expression of a viral payload gene in the genetically engineered cell when the genetically engineered cell is transfected with a recombinant virus, and wherein the shRNA binds to a binding site on an mRNA encoded by the recombinant virus. 
     
     
         7 . The genetically engineered cell of  claim 6  wherein the recombinant nucleic acid encoding at least a second shRNA. 
     
     
         8 . The genetically engineered cell of  claim 6  wherein the genetically engineered cell does not have a binding site for the shRNA in an mRNA expressed by the genetically engineered cell.