Seventy-two hours after hydrodynamic injection, both pORF and pIL21-treated humanized mice were infected with 10,000 TCID50 of CCR5-tropic HIV-1JR-CSF clone and assayed for plasma viral load 2 weeks after infection, a time point preceding detectable virus-specific cellular and antibody responses in this model33. The gene discussed is CCR5; the disease is infection.