Reproducible Isolation of Lymph Node Stromal Cells Reveals Site-Dependent Differences in Fibroblastic Reticular Cells

Within lymph nodes, non-hematopoietic stromal cells organize and interact with leukocytes in an immunologically important manner. In addition to organizing T and B cell segregation and expressing lymphocyte survival factors, several recent studies have shown that lymph node stromal cells shape the naïve T cell repertoire, expressing self-antigens which delete self-reactive T cells in a unique and non-redundant fashion. A fundamental role in peripheral tolerance, in addition to an otherwise extensive functional portfolio, necessitates closer study of lymph node stromal cell subsets using modern immunological techniques; however this has not routinely been possible in the field, due to difficulties reproducibly isolating these rare subsets. Techniques were therefore developed for successful ex vivo and in vitro manipulation and characterization of lymph node stroma. Here we discuss and validate these techniques in mice and humans, and apply them to address several unanswered questions regarding lymph node composition. We explored the steady-state stromal composition of lymph nodes isolated from mice and humans, and found that marginal reticular cells and lymphatic endothelial cells required lymphocytes for their normal maturation in mice. We also report alterations in the proportion and number of fibroblastic reticular cells (FRCs) between skin-draining and mesenteric lymph nodes. Similarly, transcriptional profiling of FRCs revealed changes in cytokine production from these sites. Together, these methods permit highly reproducible stromal cell isolation, sorting, and culture

Self-antigen presentation by dendritic cells in autoimmunity

The operation of both central and peripheral tolerance ensures the prevention of autoimmune diseases. The maintenance of peripheral tolerance requires self-antigen presentation by professional antigen presenting cells (APCs). Dendritic cells (DCs) are considered as major APCs involved in this process. The current review discusses the role of DCs in autoimmune diseases, the various factors involved in the induction and maintenance of tolerogenic DC phenotype and pinpoints their therapeutic capacity as well as potential novel targets for future clinical studies

The complex myeloid network of the liver with diverse functional capacity at steady state and in inflammation

In recent years, it has been an explosion of information regarding the role of various myeloid cells in liver pathology. Macrophages and dendritic cell (DC) play crucial roles in multiple chronic liver diseases such as fibrosis and non-alcoholic fatty liver disorders (NAFLD). The complexity of myeloid cell populations and the missing exclusive marker combination make the interpretation of the data often extremely difficult. The current review aims to summarize the multiple roles of macrophages and DCs in chronic liver diseases, especially pointing out how these cells influence liver immune and parenchymal cells thereby altering liver function and pathology. Moreover, the review outlines the currently known marker combinations for the identification of these cell populations for the study of their role in liver immunology

Extracellular vesicle profiling and their use as potential disease specific biomarker

Cell derived vesicles; in particular extracellular vesicles (EVs) such as microparticles (MPs) and microvesicles (MVs) besides exosomes are raising more and more attention as a novel and unique approach to detect diseases. It has recently become apparent, that disease specific MP signatures or profiles might be beneficial to differentiate chronic liver diseases such as non-alcoholic fatty liver disease (NAFLD) and chronic hepatitis C (CHC), to monitor their progression or possibly to assess treatment outcome. Therefore EVs might serve as a novel inexpensive and minimally invasive method to screen risk patients for the outbreak of a disease even before the initial symptoms, to follow up treatment complications and disease relapse. The purpose of the current review is to summarize already published EVs signatures for a limited number of exemplary diseases and to discuss their possible impact. Additionally, it will be discussed if the combination of EV profiling and miRNA profiling could be a future joint tool for the purpose of detecting cancer and from far larger interest to ultimately distinguish among various tumor entities. EVs might increase the chance of early detection of chronic diseases or cancers especially if applied as part of yearly health screenings in the future