Resident memory CD8+ T cells (CD8+ TRM) play a central role in tissue immunity. This thesis focusses on the formation, function and behavior of CD8+ TRM in the skin. Firstly, by making use of... Show moreResident memory CD8+ T cells (CD8+ TRM) play a central role in tissue immunity. This thesis focusses on the formation, function and behavior of CD8+ TRM in the skin. Firstly, by making use of lineage tracing technology, we show that the capacity to form TRM is instilled in CD8+ T cells before the cells enter the affected tissue and that this capacity remains fixed after a secondary immune challenge. Second, this works shows that CD8+ skin-TRM act as local sentinels that trigger a rapid and tissue-wide immune response upon foreign antigen recognition. Third, ex vivo imaging of human skin biopsies demonstrates that tissue patrol is a property of CD8+ TRM in human skin. In addition, this work describes the development of two novel technologies (i.e. the ‘Tol’ mouse strain and the ex vivo imaging technique) that can be used as such or adapted by other biomedical researchers in order to investigate key aspects of (T) cell behavior and skin biology. Understanding the signals that drive CD8+ TRM formation, and insights in the function of these cells within both healthy and diseased skin, will be essential to allow the manipulation of these populations for therapeutic benefit. Show less
Reporter proteins have become an indispensable tool in biomedical research. However, exogenous introduction of these reporters into mice poses a risk of rejection by the immune system. Here, we... Show moreReporter proteins have become an indispensable tool in biomedical research. However, exogenous introduction of these reporters into mice poses a risk of rejection by the immune system. Here, we describe the generation, validation and application of a multiple reporter protein tolerant 'Tol' mouse model that constitutively expresses an assembly of shuffled reporter proteins from a single open reading frame. We demonstrate that expression of the Tol transgene results in the deletion of CD8(+) T cells specific for a model epitope, and substantially improves engraftment of reporter-gene transduced T cells. The Tol strain provides a valuable mouse model for cell transfer and viral-mediated gene transfer studies, and serves as a methodological example for the generation of poly-tolerant mouse strains. Bresser and Dijkgraaf et al. develop the 'Tol' strain, a genetically modified mouse model that expresses a range of shuffled reporter and modifier proteins from a single open reading frame. This strain is immunologically tolerant to these reporter and modifier proteins, providing a valuable model system for cell transfer studies and virus-mediated gene transfer studies. Show less
Dijkgraaf, F.E.; Matos, T.R.; Hoogenboezem, M.; Toebes, M.; Vredevoogd, D.W.; Mertz, M.; ... ; Schumacher, T.N. 2019
Emerging data show that tissue-resident memory T (TRM) cells play an important protective role at murine and human barrier sites. TRM cells in the epidermis of mouse skin patrol their surroundings... Show moreEmerging data show that tissue-resident memory T (TRM) cells play an important protective role at murine and human barrier sites. TRM cells in the epidermis of mouse skin patrol their surroundings and rapidly respond when antigens are encountered. However, whether a similar migratory behavior is performed by human TRM cells is unclear, as technology to longitudinally follow them in situ has been lacking. To address this issue, we developed an ex vivo culture system to label and track T cells in fresh skin samples. We validated this system by comparing in vivo and ex vivo properties of murine TRM cells. Using nanobody labeling, we subsequently demonstrated in human ex vivo skin that CD8+ TRM cells migrated through the papillary dermis and the epidermis, below sessile Langerhans cells. Collectively, this work allows the dynamic study of resident immune cells in human skin and provides evidence of tissue patrol by human CD8+ TRM cells. Show less
