Mapping the accumulation of co-infiltrating CNS dendritic cells and encephalitogenic T cells during EAE

•BMDCs and T cells accumulate and interact in specific brain regions in early EAE.•DCs and T cells accumulate in periventricular brain tissues before spinal cord.•Immune cell migration through RMS is increased during neuroinflammation.•We identify primary and secondary CNS compartments of immune cell entry in EAE.

Evidence from experimental autoimmune encephalomyelitis (EAE) suggests that CNS-infiltrating dendritic cells (DCs) are crucial for restimulation of coinfiltrating T cells. Here we systematically quantified and visualized the distribution and interaction of CNS DCs and T cells during EAE. We report marked periventricular accumulation of DCs and myelin-specific T cells during EAE disease onset prior to accumulation in the spinal cord, indicating that the choroid plexus-CSF axis is a CNS entry portal. Moreover, despite emphasis on spinal cord inflammation in EAE and in correspondence with MS pathology, inflammatory lesions containing interacting DCs and T cells are present in specific brain regions.