CD4 and HIV-1 infection: Wang et al. showed that TZM.bl cells and a human CD4+ T cell line, CEMss-CCR5, transduced with lentiviral plasmids expressing Cas9 and CCR5-sgRNAs have a selective advantage during R5-tropic HIV-1 infection and confer resistance to infection with Bru-Yu2 and infectious molecular clones of transmitted/founder (T/F) HIV-1 isolates such as; pTHRO, pCH040, pWITO, pCH106 and pREJO [61].