Visualizing the transmission and dissemination of human immunodeficiency virus type 1 (HIV-1) in real time in humanized mouse models is a robust tool to investigate viral replication during treatments and in tissue reservoirs. However, the stability and expression of HIV-1 reporter genes are obstacles for long-term serial imaging . Two replication-competent CCR5-tropic HIV-1 reporter constructs were created that encode either nanoluciferase (nLuc) or a nearinfrared fluorescent protein (iRFP) upstream of . HIV-1 reporter virus replication and reporter gene expression was measured in cell culture and in humanized mice. While reporter gene expression correlated initially with plasma viremia, expression decreased ... More
Visualizing the transmission and dissemination of human immunodeficiency virus type 1 (HIV-1) in real time in humanized mouse models is a robust tool to investigate viral replication during treatments and in tissue reservoirs. However, the stability and expression of HIV-1 reporter genes are obstacles for long-term serial imaging . Two replication-competent CCR5-tropic HIV-1 reporter constructs were created that encode either nanoluciferase (nLuc) or a nearinfrared fluorescent protein (iRFP) upstream of . HIV-1 reporter virus replication and reporter gene expression was measured in cell culture and in humanized mice. While reporter gene expression correlated initially with plasma viremia, expression decreased after 4 to 5 weeks despite high plasma viremia. The reporter genes were codon optimized to remove cytosine/guanine (CG) dinucleotides, and new CO-nLuc and CO-iRFP viruses were reconstructed. Removal of CG dinucleotides in HIV-1 reporter viruses improved replication and reporter expression and . Both codon-optimized reporter viruses could be visualized during coinfection and reporter gene expression during treatment failure preceded detection of plasma viremia. While the dynamic range of CO-iRFP HIV-1 was lower than that of CO-nLuc HIV-1, both viruses could have utility in studying and visualizing HIV-1 infection in humanized mice. Animal models are important for studying HIV-1 pathogenesis and treatments. We developed two viruses each encoding a reporter gene that can be expressed in cells after infection. This study shows that HIV-1 infection can be visualized by noninvasive, whole-body imaging in mice with human immune cells over time by reporter expression. We improved reporter expression to reflect HIV-1 replication and showed that two viral variants can be tracked over time in the same animal and can predict failure of antiretroviral therapy to suppress virus.
