CD34 and infection: The combined anti-viral effects of the C46 fusion inhibitor with a short hairpin RNA to CCR5 using a self-inactivating (SIN) lentiviral vector have been reported to stably downregulate CCR5, express C46, and protect against a broad range infection of HIV-1 strains in human cell lines, primary PBMCs, and human CD34+ HSPCs18.