Multiscale Imaging of HIV-1 Transmission in Humanized Mice

HIV transmission within lymphoid tissues remains incompletely characterized at the level of individual cells and virions. Here we visually describe our approach to understanding HIV-1 dissemination at different levels of volume and resolution within lymphoid tissues from HIV-1-infected humanized mice. We combined tissue clearing techniques, immunostaining, and light sheet fluorescence microscopy to visualize large-volumes of intact tissue with single-cell resolution from HIV-1-infected humanized mice. In parallel, we imaged adjacent regions of tissue using electron microscopy and electron tomography to gain 3D ultrastructural information about the same tissue samples. This approach can provide spatial information about the density and distribution of target cells, HIV-1-infected cells, and individual budding and free-virions within lymphoid tissues. Multiscale imaging of HIV-1 infected tissues from humanized mice can provide insight into the biological mechanisms of HIV-1 transmission through the correlation of global pathology with structural details and these methods are directly translatable to other animal models and human clinical samples.