2 results
373 Identification of potential targets for immunotherapy in a cynomolgus macaque model of Ebola virus disease
- Part of
- Timothy Wanninger, Omar A. Saldarriaga, Daniel E. Millian, Jason E. Comer, Kamil Khanipov, George Golovko, Slobodan Paessler, Heather L. Stevenson
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- Journal:
- Journal of Clinical and Translational Science / Volume 7 / Issue s1 / April 2023
- Published online by Cambridge University Press:
- 24 April 2023, p. 111
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- Article
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- You have access Access
- Open access
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OBJECTIVES/GOALS: Ebola virus infection causes severe disease and liver injury in humans. Macrophages contribute to inflammatory signaling and are prevalent in the liver. We assessed the activation status, including therapeutic target expression, of hepatic macrophages. METHODS/STUDY POPULATION: We compared formalin-fixed, paraffin-embedded liver tissue from terminal Ebola virus-infected and uninfected control cynomolgus macaques, a gold-standard model for human disease. We characterized region-specific protein and whole transcriptome expression in these tissues using GeoMx Digital Spatial Profiling. Macrophage (CD68+) and leukocyte (CD45+) accumulation in liver tissue was quantified by immunofluorescence image analysis using digital pathology software. RESULTS/ANTICIPATED RESULTS: Macrophage-specific (CD68+) regions in the liver of Ebola virus-infected macaques demonstrated a shift towards an inflammatory gene expression profile, as compared to those from healthy control tissue. These regions showed differential expression of monocyte/macrophage differentiation, antigen presentation, and T cell activation gene sets, which were associated with decreased MHC-II allele expression. Moreover, macrophage-specific regions in the infected macaques showed enriched expression of genes or proteins associated with known immunomodulatory therapeutics, including S100A9, IDO1, and CTLA-4. DISCUSSION/SIGNIFICANCE: These data demonstrate that hepatic macrophages express an inflammatory phenotype, that their ability to present antigens to the adaptive immune system may be impaired, and that they express therapeutically targetable markers for immunomodulation of these cells during Ebola virus infection.
14 - Stem Cell Tracking
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- By Daniel Golovko, Department of Radiology, Stanford University, Stanford, CA, Ramsha Khan, Department of Radiology, Stanford University, Stanford, CA, Heike Daldrup-Link, Department of Radiology, Stanford University, Stanford, CA
- Edited by Hossein Jadvar, Heather Jacene, Michael Graham
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- Book:
- Molecular Imaging
- Published online:
- 22 November 2017
- Print publication:
- 16 November 2017, pp 65-75
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- Chapter
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Summary
Stem cell therapies aim to replace abnormal, injured, or lost cells in organs with little or no capacity for self-renewal and provide hope for cures of devastating diseases with previously presumed irreversible functional loss, such as myocardial or brain infarction, blindness, paraplegia, diabetes mellitus, and degenerative or post-traumatic bone/ cartilage defects, among many others. In order to treat a cellular and/or functional deficit in a selected target organ, stem cells or stem-cell-derived cell populations are administered systemically (e.g. into the blood system), into a cavity (e.g. into a brain ventricle), or directly into target tissue (e.g. into myocardium). Many questions arise about the fate of the administered cells. Do the stem cells actually end up where they are desired (homing)? Do they survive? Do they integrate themselves with the host tissue (engraftment)? If undifferentiated stem cells are transplanted, do these cells differentiate into the desired specialized progenies and restore the impaired function of the target tissue? Does the host's immune system tolerate or reject the transplanted cells? Noninvasive imaging techniques can address these questions and help to develop and monitor successful approaches for stem-cell-mediated tissue regeneration.
Methods to Visualize Stem Cell Homing and Engraftment
There are various classical methods of showing distribution of stem cells in the body. Most rely on introducing a marker into the graft material that can be specifically stained after explantation. One common method is the transfection of stem cells with a plasmid containing lacZ. lacZ encodes β-galactosidase, an enzyme not normally found in human cells. After explantation, fixation, and staining of material to be examined, marked cells will stain while unmarked cells will not. This method is applicable only in animal models. Another common pre-clinical method is the transfection of stem cells with luciferase genes. Luciferase catalyzes a two-step chemical reaction of the substrate luciferin, which leads to bioluminescence detectable in vivo by an optical imaging system. Photon generation following intravenous administration of luciferin takes place exclusively at the site of luciferase expression; therefore, the target-to-background signal ratio is extremely high. Bioluminescence imaging has been used for cell tracking in small animal models. However, limitations for human application for cell tracking are poor spatial resolution, the need to inject high doses of luciferin to generate a contrast effect, and potential immunogenicity of the foreign gene protein, luciferase.