Abstract: Disclosed herein are cells including pluripotent stem cells that conditionally express an immunosuppressive factor and related methods of their use and generation. In some embodiments, the cells disclosed do not express MHC I and MHC II human leukocyte antigens, and in some cases, also do not express one or more TCR complexes. In some embodiments, hypoimmunogenicity of the cells is controlled by activation of a controllable expression system upon contacting the cells with a specific factor or agent.

Abstract: An in vivo method of modifying a genome of a target cell in a mammalian subject is described. The method includes administering an effective amount of a transducer cell to the subject, where the transducer cell includes a regulated viral vector delivery system (RVVDS) for producing and releasing viral transduction particles (VTPs) when the transducer cell is exposed to inducing conditions, and each VTP comprises a nucleic acid encoding a genome modification system (GMS) comprising a genome modification protein and one or more elements that regulate expression or activity of the genome modification protein in a mammalian cell.