Longitudinal imaging of early HIV infection in situ
Creators: name: University Of California Office Of The President
Publisher: name: University of California Office of the President
publisherIdentifier: https://ror.org/00dmfq477
publisherIdentifierScheme: ROR
Year: 2024

description: The current HIV/AIDS epidemic is an important public health issue, both globally with an estimated 35 million infected individuals, and locally in the state of California with over 130,00 individuals estimated currently living with HIV/AIDS. Many newly infected individuals do not realize they have HIV until several weeks later when they often present with flu-like symptoms and high levels of virus in the blood. Unfortunately, by this time, the virus has already established productive infection and spread to the major disease sites in the body. Lymphoid tissues (gut, spleen, lymph nodes) contain large concentrations of immune cells and are the locations where most HIV/AIDS related pathogenesis occurs. Little is known about the early stages of HIV-infection when the virus spreads from the initial site of transmission to lymphoid tissue sites throughout the body. The goals of this study are to combine new microscopic imaging techniques with emerging animal models of HIV-infection to visually define how individual virions and infected cells establish productive infection and understand and how early stages of infection proceed within lymphoid tissue. Recently developed animal models of HIV-infection provide an alternative platform for conducting studies to understand HIV-infection in an environment similar to that of an infected patient. "Humanized" mice, for example, allow repopulation of immune-deficient animals with human immune cells. Research studies with these animal models have successfully recapitulated important aspects of HIV/AIDS from infected patients, including sexual transmission, systemic virus spread, immune-cell depletion, and development of AIDS-like symptoms. Advances in light and electron microscopy are allowing the 3D analysis of tissues at previously unattainable levels of volume and resolution. Light sheet fluorescence microscopy is a technique that generates a thin plane of light to optically section samples at high speed and single-cell resolution. This technique has recently allowed fluorescence imaging of entire organs from mice at single-cell resolution. 3D electron microscopy allows the imaging of tissues at sub-cellular resolution, identification of individual HIV virions, and delineation of the spatial relationships between virions and infected cells within tissue. The combination of both light and electron microscopy analysis of samples can allow the correlation of imaging studies at multiple levels of volume and resolution. Our proposed studies aim to infect "humanized" mice with HIV and utilize advanced 3D light and electron microscopy techniques to image HIV-infected lymphoid tissue over time as the virus spreads from the initial site of infection to distant locations. These studies will allow the direct visualization of HIV-infected cells and individual virions in lymphoid tissue from "humanized" mice at multiple levels of volume and resolution during the establishment of productive infection. By directly visualizing HIV-infected lymphoid tissues over time, in 3D, at multiple levels of resolution, these studies can identify routes of virus spread, localize reservoirs of virus and infected cells over time, and probe underlying biological mechanisms of virus spread. They will also identify future targets to be explored for therapeutic benefit and will be directly translatable to other animal studies and the analysis of samples from HIV-infected patients.