Poster Presentation The 13th International Congress of the Immunology of Diabetes Society 2013

Characterization of the healthy interaction between the human immune cells and the pancreatic islet (#180)

Miljana Radenkovic 1 , Christina Uvebrant 1 , Oskar Skog 2 , Olle Korsgren 2 , Corrado Cilio 1
  1. Autoimmunity Unit, Dep. of Clinical science, Lund University, Malmö, Sweden
  2. Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University Hospital, Uppsala, Sweden

The current view of type T1D is that it is a T cell mediated disease in which both CD4 and CD8 lymphocytes infiltrate the pancreatic islets, destroy insulin-producing beta cells and consequently cause diabetes. In this study we aimed at investigating the presence of immune cells within non-diabetic human islets and characterize their frequency and phenotype.

Human islets were obtained from organ donors of non-diabetic individuals. A sensitive multicolor flow cytometry analysis (IsletsFACS) of single cells suspension from isolated islets was used to define the frequency and phenotype of activated and memory T cells as well as frequency of NK and B cells. Insulin and glucagon expressing cells within the islets was also assessed. Moreover CD8+ T cells were sorted and their Vβ repertoire examined. Remarkably, lymphocytes were present in all 54 human islet samples examined. Generally, the frequency of B and NK cells were low in most of the samples, consisting of less than 5% of the lymphocyte compartment. Interestingly, about 80% of the lymphocytes were CD3+ and amongst these T cells the majority were CD8+. The central memory and effector memory phenotypes dominated both the CD8+ and CD4+ T cells, suggesting a specific recruitment of T cells rather than contaminating lymphocytes.

In conclusion, we have demonstrated the presence of lymphocytes in pancreatic islets of human non-diabetic donors and the remarkable biased towards CD8+ T cell as well as their exquisite memory phenotype. To characterize the physiological interaction between immune cells and the healthy islets will be determinant to understand the disease-related characteristic of T1D.