Lymphoid Tissue Development - CNRS URA 1961
Ontogeny programs the development of lymphocytes and their recruitment to secondary lymphoid tissues. These tissues collect antigens and mount adaptive immune responses to potential pathogens. The recruitment, activation and migration of lymphocytes require a highly organized network of stromal and hematopoietic cells that orchestrate each step in the development of an immune response. Furthermore, an immune response induces the development of the immune system itself by promoting the generation of new lymphoid tissues and the differentiation of lymphocytes. In that context, microbes, and more generally injured cells and tissues, are not only triggers and targets of destructive immunity, but also the architects of a mature immune system. The best example of such a constructive partnership between microbes and the immune system is found in the intestine, where billions of bacteria have established a mutualistic relationship with the host not only for optimal digestion, but also for robust defense against pathogens and injury. We have recently shown how commensal bacteria induce ‘physiologic infammation’ and the consequent genesis of lymphoid tissues involved in the maintenance of intestinal homeostasis. Our projects aim at understanding the impact of symbiotic microbiota and inflammation on the development of the immune system. In particular, we dissect the role of innate lymphoid cells and active stromal cells in homeostasis and disease.