B Cells Drive MHC Class I-Restricted CD4 T Cells to Induce Spontaneous Central Nervous System Autoimmunity

Area of Science:

• Neuroimmunology
• T cell immunology
• Autoimmunity

Background:

• Multiple sclerosis (MS) is a T cell-mediated autoimmune disease of the central nervous system (CNS).
• The precise roles of CD8 T cells and B cells in MS pathogenesis remain incompletely understood.
• Understanding lymphocyte effector functions is crucial for developing effective MS therapies.

Purpose of the Study:

• To investigate the contribution of T cells with a transgenic TCR specific for myelin basic protein (MBP) to CNS autoimmunity.
• To explore the mechanisms underlying spontaneous CNS autoimmunity in a mouse model of MS.
• To identify key cellular players and pathways involved in MS pathogenesis.

Main Methods:

• Utilized a mouse model of experimental autoimmune encephalomyelitis (EAE) with T cells expressing an MHC class I-restricted transgenic TCR specific for MBP.
• Induced acute EAE via virus infection to trigger CD8 T cell responses.
• Analyzed spontaneous CNS autoimmunity, IFN-γ deficiency effects, and the role of CD4 T cells and B cells in disease development.

Main Results:

• Virus infection initiated acute EAE mediated by cytotoxic CD8 T cells in an IFN-γ- and perforin-dependent manner.
• Spontaneous CNS autoimmunity developed in TCR-transgenic mice, accelerated by IFN-γ deficiency.
• Disease was associated with CD4 T cells producing TNF-α and B cells cross-presenting MBP, with B cell depletion halting progression.

Conclusions:

• This study presents a novel model of spontaneous CNS autoimmunity resembling MS.
• Distinct CD4 T cell populations and B cell cross-presentation are critical in this MS model.
• Findings highlight the complex interplay of immune cells in CNS autoimmunity and potential therapeutic targets for MS.