A Picture is Worth a Thousand Words
Viruses are fascinating on many levels. One of them is visually. Scientific images of viruses, HIV included, can be quite arresting and often blur the lines between science and art (see The Trimer Transformed, IAVI Report, Vol. 19, Issue 1). At the two-day workshop, “Harnessing Novel Imaging Approaches to Guide HIV Prevention and Cure Discoveries,” many of these striking and important images were on display. This meeting was sponsored by the Division of AIDS at the US National Institutes of Health (NIH) and the Global HIV Vaccine Enterprise. IAVI Report invited two of the workshop’s co-chairs, Constantinos Petrovas of the NIH and Jake Estes of the Frederick National Laboratory for Cancer Research and Leidos Biomedical Research Inc., to curate a selection of some of the top images from the meeting and to describe how scientists are using these images to guide the development of new strategies to prevent HIV infection or even help identify an effective cure. Oh, and they are rather stunning too. —Kristen Jill Kresge
|Curating a Conference|
The aim of the workshop was to bring leading HIV and non-HIV imaging experts together to discuss cutting-edge technologies and approaches in this field to promote innovation, collaboration, and acceleration of scientific progress in HIV prevention, pathogenesis, and cure research. Novel imaging platforms that allow for the visualization and multi-dimensional and multi-parametric quantitative analysis of the virus at the cellular, tissue, and organism level were presented. The presentations covered a broad range of in vitro, ex vivo, and in vivo imaging approaches for a comprehensive analysis of the pathology of the virus and the immune cell dynamics involved in the interplay between the virus and the immune system. The emerging technologies presented are being applied to understand HIV/simian immunodeficiency virus (SIV) transmission and mechanisms of prevention, the spatial micro-anatomy of the immune system, the biology of HIV/SIV reservoir formation and viral persistence, and disease-driven pathology, leading to the development of new concepts and strategies to eliminate the virus. —Constantinos Petrovas and Jake Estes
Imaging T-cell Motility
This image, created using ex vivo two photon confocal imaging techniques, shows T- and B-cell mobility with respect to fibrotic lymphoid tissue damage. This technology allows for the real-time analysis of immune cell interactions within their natural tissue environment. CD4+ T cells (orange) and B cells (blue) were incubated on top of HIV-infected lymph node biopsy slices. Image generated by Jason Mitchell and Brian Fife.
Multiplexed Ion Beam Imaging
The use of spectrometry-based imaging technologies, such as that used here, opens new avenues for in-depth analysis of complex cell populations in their native tissue environment. Multiplexed ion beam imaging (MIBI) uses antibodies tagged with elemental mass tags in combination with secondary ion mass spectrometry to visualize dozens of proteins simultaneously in a single tissue section. Examples of MIBI data are shown as color overlays.
This image demonstrates how novel mouse models provide unique opportunities for in vivo visualization of immune system dynamics and delineate the complexity of the development of immune responses. Image on left, taken using multiphoton microscopy, is pre-immunization. Imagine on right, post-immunization, shows germinal center formation in a mouse lymph node.
Infection-induced Germinal Centers
Researchers applied multiplexed confocal imaging assays for the simultaneous quantitative analysis of several relevant immune cell types that mediate the development of pathogen/immunogen-specific B-cell responses. Non-human primate lymph nodes obtained 14 days after infection with wild type (SIVmac239) or a CD4-independent (iMac239) SIV are shown. Germinal centers (defined by CD20 in blue) and follicular CD4+ T cells (defined by CD4 in yellow and PD-1 in pink) with respect to expression of Bcl-6 in red and Ki67 in green are shown.
Antibodies in Mouse Lymph Node
The multi-dimensional high-resolution confocal microscopy analysis employed to create this image provides critical information for the understanding of the local organization and compartmentalization of relevant cells during the development of immune responses in a mouse lymph node. This helps researchers understand the underlying processes involved in inflammation and the immune response. This image shows a mouse lymph node stained with antibodies to detect various innate and adaptive immune populations, as well as stromal structural elements.
The work by Haase and colleagues allows us to visualize the local dynamics of SIV infection and the adaptive immune responses soon after infection, showing that the mobilization of the immune system is “too little, too late.” While there are many T cells in spatial proximity to infected cells, the infected cells are numerous and the target to effector cell ratio was correlated with only partial control of infection.
Tracking the Virus in Tissue
This image showcases the power and utility of a novel imaging technology that allows for the detailed characterization of HIV-infected cells in situ. This technique should provide critical information regarding virus dissemination, establishment of latency, and the cellular populations and anatomical sites where virus and infected cells persist. Viral DNA is shown in red with CD3+ T cells in green and CD68+/CD163+ myeloid lineage cells in blue. The arrows point to examples of “superinfected” T cells that contain multiple copies of viral DNA per cell.