Efficient culture of CD8⁺ T cells from the islets of NOD mice and their use for the study of autoreactive specificities

During progression to type 1 diabetes (T1D), the pancreatic islets of humans and of the widely studied mouse model of T1D, the nonobese diabetic (NOD) mouse, are infiltrated by cells of the immune system. Here we report that infiltrated mouse islets ("translucent islets") can be identified visually. We demonstrate the use of an efficient method for the isolation and culture of the islet-infiltrating cells of NOD mice, which results in a high percentage of CD8⁺ T cells after seven days, with minimal manipulation. We show that islet-infiltrating cells exit the islets soon after they are placed in culture and can be used in flow cytometric experiments several hours later. Importantly, we demonstrate that the cultured cells are antigen-responsive and that specificities present at the beginning of the culture are generally still present on day seven. In addition, some reactivities are undetected without culture, supporting the validity of the seven-day expansion period. This technique greatly facilitates investigations of the CD8⁺ T cell reactivities that play a pivotal role in the demise of pancreatic beta cells leading to the development of T1D.