Cellular and molecular events in the localization of diabetogenic T cells to islets of Langerhans

B Calderon, JA Carrero, MJ Miller… - Proceedings of the …, 2011 - National Acad Sciences
B Calderon, JA Carrero, MJ Miller, ER Unanue
Proceedings of the National Academy of Sciences, 2011National Acad Sciences
Understanding the entry of autoreactive T cells to their target organ is important in
autoimmunity because this entry initiates the inflammatory process. Here, the events that
lead to specific localization of diabetogenic CD4 T cells into islets of Langerhans resulting in
diabetes were examined. This was evaluated in two models, one in which T cells specific for
a hen-egg white lysozyme (HEL) peptide were injected into mice expressing HEL on β cells
and the other using T cells in the nonobese diabetic mouse strain, which develops …
Understanding the entry of autoreactive T cells to their target organ is important in autoimmunity because this entry initiates the inflammatory process. Here, the events that lead to specific localization of diabetogenic CD4 T cells into islets of Langerhans resulting in diabetes were examined. This was evaluated in two models, one in which T cells specific for a hen-egg white lysozyme (HEL) peptide were injected into mice expressing HEL on β cells and the other using T cells in the nonobese diabetic mouse strain, which develops spontaneous diabetes. Only T cells specific for β-cell antigens localized in islets within the first hours after their injection and were found adherent to intraislet dendritic cells (DCs). DCs surrounded blood vessels with dendrites reaching into the vessels. Localization of antigen-specific T cells did not require chemokine receptor signaling but involved class II histocompatibility and intercellular adhesion molecule 1 molecules. We found no evidence for nonspecific localization of CD4 T cells into normal noninflamed islets. Thus, the anatomy of the islet of Langerhans permits the specific localization of diabetogenic T cells at a time when there is no inflammation in the islets.
National Acad Sciences