[HTML][HTML] Microglia and perivascular macrophages act as antigen presenting cells to promote CD8 T cell infiltration of the brain

EN Goddery, CE Fain, CG Lipovsky… - Frontiers in …, 2021 - frontiersin.org
EN Goddery, CE Fain, CG Lipovsky, K Ayasoufi, LT Yokanovich, CS Malo, RH Khadka
Frontiers in immunology, 2021frontiersin.org
CD8 T cell infiltration of the central nervous system (CNS) is necessary for host protection
but contributes to neuropathology. Antigen presenting cells (APCs) situated at CNS borders
are thought to mediate T cell entry into the parenchyma during neuroinflammation. The
identity of the CNS-resident APC that presents antigen via major histocompatibility complex
(MHC) class I to CD8 T cells is unknown. Herein, we characterize MHC class I expression in
the naïve and virally infected brain and identify microglia and macrophages (CNS-myeloid …
CD8 T cell infiltration of the central nervous system (CNS) is necessary for host protection but contributes to neuropathology. Antigen presenting cells (APCs) situated at CNS borders are thought to mediate T cell entry into the parenchyma during neuroinflammation. The identity of the CNS-resident APC that presents antigen via major histocompatibility complex (MHC) class I to CD8 T cells is unknown. Herein, we characterize MHC class I expression in the naïve and virally infected brain and identify microglia and macrophages (CNS-myeloid cells) as APCs that upregulate H-2Kb and H-2Db upon infection. Conditional ablation of H-2Kb and H-2Db from CNS-myeloid cells allowed us to determine that antigen presentation via H-2Db, but not H-2Kb, was required for CNS immune infiltration during Theiler’s murine encephalomyelitis virus (TMEV) infection and drives brain atrophy as a consequence of infection. These results demonstrate that CNS-myeloid cells are key APCs mediating CD8 T cell brain infiltration.
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