AUTHOR=Strominger Itai , Elyahu Yehezqel , Berner Omer , Reckhow Jensen , Mittal Kritika , Nemirovsky Anna , Monsonego Alon TITLE=The Choroid Plexus Functions as a Niche for T-Cell Stimulation Within the Central Nervous System JOURNAL=Frontiers in Immunology VOLUME=9 YEAR=2018 URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2018.01066 DOI=10.3389/fimmu.2018.01066 ISSN=1664-3224 ABSTRACT=

The choroid plexus (CP) compartment in the ventricles of the brain comprises fenestrated vasculature and, therefore, it is permeable to blood-borne mediators of inflammation. Here, we explored whether T-cell activation in the CP plays a role in regulating central nervous system (CNS) inflammation. We show that CD4 T cells injected into the lateral ventricles adhere to the CP, transmigrate across its epithelium, and undergo antigen-specific activation and proliferation. This process is enhanced following peripheral immune stimulation and significantly impacts the immune signaling induced by the CP. Ex vivo studies demonstrate that T-cell harboring the CP through its apical surface is a chemokine- and adhesion molecule-dependent process. We suggest that, within the CNS, the CP serves an immunological niche, which rapidly responds to peripheral inflammation and, thereby, promotes two-way T-cell trafficking that impact adaptive immunity in the CNS.