The article provides information on a study conducted by E. E. Perez and colleagues to determine the potential of a genome-editing approach targeting the CC-chemokine receptor CCR5 to reconstitute immune function in HIV individuals by creating CD4 . It mentions that the primary human CD4 T cells were transduced with CCR5-zinc-finger nucleases (ZFNs) to explore the clinical feasibility of the approach, and later propagated in culture.