CCR5 and HIV infectious disease: Since individuals lacking CCR5 have the advantage of being protected from HIV infection, the study utilized CRISPR–Cas9 to edit the CCR5 gene in MCM embryos, introduced a double allelic deletion of the CCR5 gene into MCM embryos, and improved the in vitro fertilizationmethodology to create MCMs with the CCR5 mutation, which could be used in the exploration of HIV therapies.184