Fig. 1.

Mechanism of ChP immune response to LPS infection. a Immune landscape of ChP under homoeostasis depicting the ChP macrophage populations, which reside in the stromal region and on the apical CSF-containing surface of the epithelial wall. b Acute immune response phase to intracerebroventricular delivery of LPS. Retnlg⁺ neutrophils and Ccr2⁺ Plac8⁺ monocytes enter the ChP via the blood stream into the stroma and through the epithelial barrier into the CSF tissue. Chil1⁺ Icam1⁺ inflamed epithelial cells, present during acute inflammation, coordinate immune recruitment and activation in the ChP via the expression of metalloproteases, chemokines and adhesion molecules. c By 72 h after LPS treatment, epiplexus macrophages support the resolution of inflammation by phagocytosing immune infiltrates and epithelial cell debris as well as secreting occludin, which contributes to epithelial barrier repair