The spleen is a gatekeeper of systemic immunity where immune responses against blood-borne pathogens are initiated and sustained. T cell responses against infections are initiated through coordinated interactions with dendritic cells within secondary lymphoid organs. However, delineation of the spatiotemporal interactions between CD8 T cells and dendritic cells required for antiviral immunity remains ill-defined, particularly in the spleen. Fibroblasts of the spleen, also known as fibroblastic reticular cells, form a network that support immune cell migration and homeostasis. While these fibroblasts respond dynamically to infection, and this is hypothesised to favour the induction of immune responses, how these cells contribute to the orchestration of antiviral T cell responses is still largely unknown. In this talk, I will present our latest work on how fibroblastic reticular cells regulate antiviral immune responses in the spleen. We uncovered a fundamental role for splenic fibroblasts for the induction of T cell responses through support for dendritic cell maturation, cytotoxic T cell generation, and formation of protective memory T cells.

Yannick Alexandre is invited by Julie Helft.