Acknowledgement
We thank Boris Fehse and the NIH AIDS Research and Reference Reagent Program for providing plasmids, Kay Ole Chmielewski for help with OT analysis, Ilona Skatulla and Petra Scheliga-Marschner for technical support, the Lighthouse Core Facility (Medical Center - University of Freiburg) for flow cytometry support, and the Blood Donation Center (Medical Center - University of Freiburg) for providing PBMCs.
This work was supported by a grant of the German Federal Ministry of Education and Research (BMBF-01EO0803 to T.I.C. and T.Ca.) and a funded research cooperation with Cellectis (ZVS20170614 to T.I.C. and T.Ca.).