Contributions
Abstract: P744
Type: Poster Sessions
Abstract Category: Pathology and pathogenesis of MS - Experimental models
Background: Multiple sclerosis (MS) is a neuroinflammatory disorder characterized by infiltration of CD4 + T cells into the central nervous system (CNS). Within the CNS, T cells are re-activated by interaction with a local MHC-II + antigen presenting cell (APC). Monocyte derived dendritic cells (moDC) are thought to be the dominant APC in settings of inflammation such as EAE. The role of classical dendritic cells (cDC) is unclear.
Objectives: The aim of this study is to investigate the role of MHC-II + APC subsets in CNS autoimmunity using the animal model experimental autoimmune encephalomyelitis (EAE).
Methods: EAE was induced by adoptive transfer of myelin-primed CD4+ Th17 cells. CNS cells were analyzed by flow cytometry and immunofluorescence. APC were sorted by FACS and co-cultured with myelin-specific T cells to assess antigen presentation. Dendritic cells were depleted by diphtheria toxin (DT) in mice with DC-specific expression of the DT receptor.
Results: We sorted DC subsets and B cells from the spinal cord at peak EAE and co-cultured them with CD4 T cells from 2D2 transgenic mice, which express a T cell receptor specific for a peptide fragment of myelin oligodendrocyte glycoprotein (MOG 35-55). Contrary to expectation, CNS-infiltrating B cells and cDC, but not moDC, were able to activate 2D2 T cells ex vivo. cDC were the only APC subset capable of presenting a larger fragment of MOG polypeptide for presentation to the 2D2 T cells.
In the adoptive transfer EAE model, encephalitogenic T cells are initially activated in the uninflamed CNS. We identified MHC-II+ cDC and B cells, but few activated microglia or moDC, in the brain, meninges, or spinal cords of unmanipulated mice. cDC isolated from the naïve CNS were able to activate MOG-specific T cells directly ex vivo. In subsequent studies we found that cDC expand in the meninges and brain during EAE progression. B cell deficient mice are susceptible to EAE, so we hypothesized that cDC are critical for disease initiation. To deplete cDC in vivo, we administered DT to mice with DC-specific expression of the DT receptor prior to the adoptive transfer of MOG-reactive Th17 cells. Depletion of cDC significantly reduced the incidence of disease.
Conclusions: cDC are normally present in the meninges and are potent APC for the activation of infiltrating encephalitogenic T cells. cDC, and the factors that drive their expansion in the CNS, should be considered candidate therapeutic targets in MS.
Disclosure: Patrick Duncker: Nothing to disclose
David Giles: Nothing to disclose
Niki Wilkinson: Nothing to disclose
Jesse Washnock-Schmid: Nothing to disclose
Benjamin Segal: Nothing to disclose
Abstract: P744
Type: Poster Sessions
Abstract Category: Pathology and pathogenesis of MS - Experimental models
Background: Multiple sclerosis (MS) is a neuroinflammatory disorder characterized by infiltration of CD4 + T cells into the central nervous system (CNS). Within the CNS, T cells are re-activated by interaction with a local MHC-II + antigen presenting cell (APC). Monocyte derived dendritic cells (moDC) are thought to be the dominant APC in settings of inflammation such as EAE. The role of classical dendritic cells (cDC) is unclear.
Objectives: The aim of this study is to investigate the role of MHC-II + APC subsets in CNS autoimmunity using the animal model experimental autoimmune encephalomyelitis (EAE).
Methods: EAE was induced by adoptive transfer of myelin-primed CD4+ Th17 cells. CNS cells were analyzed by flow cytometry and immunofluorescence. APC were sorted by FACS and co-cultured with myelin-specific T cells to assess antigen presentation. Dendritic cells were depleted by diphtheria toxin (DT) in mice with DC-specific expression of the DT receptor.
Results: We sorted DC subsets and B cells from the spinal cord at peak EAE and co-cultured them with CD4 T cells from 2D2 transgenic mice, which express a T cell receptor specific for a peptide fragment of myelin oligodendrocyte glycoprotein (MOG 35-55). Contrary to expectation, CNS-infiltrating B cells and cDC, but not moDC, were able to activate 2D2 T cells ex vivo. cDC were the only APC subset capable of presenting a larger fragment of MOG polypeptide for presentation to the 2D2 T cells.
In the adoptive transfer EAE model, encephalitogenic T cells are initially activated in the uninflamed CNS. We identified MHC-II+ cDC and B cells, but few activated microglia or moDC, in the brain, meninges, or spinal cords of unmanipulated mice. cDC isolated from the naïve CNS were able to activate MOG-specific T cells directly ex vivo. In subsequent studies we found that cDC expand in the meninges and brain during EAE progression. B cell deficient mice are susceptible to EAE, so we hypothesized that cDC are critical for disease initiation. To deplete cDC in vivo, we administered DT to mice with DC-specific expression of the DT receptor prior to the adoptive transfer of MOG-reactive Th17 cells. Depletion of cDC significantly reduced the incidence of disease.
Conclusions: cDC are normally present in the meninges and are potent APC for the activation of infiltrating encephalitogenic T cells. cDC, and the factors that drive their expansion in the CNS, should be considered candidate therapeutic targets in MS.
Disclosure: Patrick Duncker: Nothing to disclose
David Giles: Nothing to disclose
Niki Wilkinson: Nothing to disclose
Jesse Washnock-Schmid: Nothing to disclose
Benjamin Segal: Nothing to disclose