When immunity multitasks: type 2 pathways power thymus regeneration.

αβT-cells are an essential cellular component of the vertebrate immune system. As the sole site of their production, the thymus represents a key orchestrator of the immune system. Despite this importance, intrathymic T-cell development is a fragile process, and the detrimental impact of multiple environmental, physiologic and therapeutic factors on thymus function is long known. With work performed over the past few decades, we now have a clearer understanding of the ability of the thymus to fight back against tissue damage, through its capacity for endogenous regeneration. Here, pre-clinical mouse models have been of key importance in revealing the presence of multiple intrathymic signalling pathways that act to rebuild the thymus and restore T-cell production and immunity following damage. Of these reported pathways, my own lab has focussed on identifying and studying an intrathymic network that consists of multiple cellular and molecular regulators of type 2 immune responses. At the recent Croatian Society for Immunology congress, I described our work on the role of this network in thymus regeneration, including IL33, ILC2 and eosinophils. In addition, I also highlighted the work of other laboratories in this area of thymus biology, and summarised similarities in the way type 2 immune components regulate tissue regeneration in both thymic and non-thymic tissues. Overall, from the considerable efforts of many researchers, we are hopefully left with a better understanding of how the immune system regulates tissue repair following damage, including one of the tissues that is of key importance in its own functioning.