BioProject

Immune protection of the body cavities depends on the swift activation of innate and adaptive immune responses in non-classical secondary lymphoid organs known as fat-associated lymphoid clusters (FALCs). More...

Immune protection of the body cavities depends on the swift activation of innate and adaptive immune responses in non-classical secondary lymphoid organs known as fat-associated lymphoid clusters (FALCs). While it is well-established that fibroblastic reticular cells (FRCs) are an integral component of the immune-stimulating infrastructure of lymph nodes and other classical secondary lymphoid organs, it has remained elusive whether and how FRCs in FALCs contribute to peritoneal immunity. Using FRC-specific gene targeting, we found that FALCs are underpinned by an elaborated FRC network and that initiation of peritoneal immunity was governed through FRC activation via MyD88-dependent innate immunological sensing. FRC-specific ablation of Myd88 expression blocked recruitment of inflammatory monocytes into FALCs and subsequent CD4+ T cell-dependent B-cell activation. Moreover, containment of Salmonella infection was compromised in conditionally Myd88-deficient mice indicating that FRCs in FALCs function as initial checkpoint in the orchestration of protective immune responses in the peritoneal cavity. Less...