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Ann N Y Acad Sci. 2007 Apr;1103:179-91. Epub 2007 Mar 21.

Antigen presentation in the CNS by myeloid dendritic cells drives progression of relapsing experimental autoimmune encephalomyelitis.

Author information

1
Department of Microbiology, Northwestern University Medical School, Chicago, IL 60611, USA. s-d-miller@northwestern.edu

Abstract

Chronic progression of relapsing experimental autoimmune encephalomyelitis (R-EAE), a mouse model of multiple sclerosis (MS), is dependent on the activation of T cells to endogenous myelin epitopes, that is, epitope spreading. This review focuses on the cellular and molecular mechanisms underlying the process of epitope spreading. Surprisingly, activation of naïve T cells to endogenous myelin epitopes in SJL mice undergoing R-EAE occurs directly in the central nervous system (CNS), a site generally perceived to be immunologically privileged. Determination of the antigen presentation capacity of antigen-presenting cell (APC) populations purified from the CNS of mice with established R-EAE shows that peripherally derived CD11b(+)CD11c(+)CD45(hi) myeloid dendritic cells (mDCs) most efficiently present endogenous myelin antigens to activate both preactivated effector myelin-specific T cells and naïve T cells. The mDCs, which drive epitope spreading, preferentially polarize pathogenic Th17 responses correlating with their enhanced expression of TGF-beta1, IL-6, and IL-23. Both B220(+)CD11c(+) plasmacytoid (pDCs) and CD8alpha(+)CD11c(+) (CD8 DCs) were superior to CD11b(+)CD11c(-)CD45(hi) macrophages, but less efficient than mDCs at presenting endogenous peptide to induce Th17 cells. In contrast, CNS-resident CD11b(+)CD11c(-)CD45(low) microglia purified from the inflamed CNS were found to be largely incapable of activating either naïve or effector T cells.

PMID:
17376826
DOI:
10.1196/annals.1394.023
[Indexed for MEDLINE]

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