Highly cytopathic CXCR4-tropic virus strains were not considered for these studies because a recent study demonstrated that HIV-1 infection of MDM with CXCR4-tropic virus induces productive HIV-1 replication in MDM until day 7pi, and then it decreases drastically until it is not detected at day 10pi due to viral-induced cell death55. Here, CXCR4 is linked to HIV-1 infection.