CD40 Drives Central Nervous System Autoimmune Disease by Inducing Complementary Effector Programs via B Cells and...

Area of Science:

• Immunology
• Neuroimmunology
• Autoimmunity

Background:

• Costimulatory CD40 is vital in autoimmune diseases like experimental autoimmune encephalomyelitis (EAE), a model for multiple sclerosis (MS).
• The precise mechanisms by which CD40 contributes to autoimmune disease pathogenesis remain incompletely understood.

Purpose of the Study:

• To elucidate the role of CD40 in orchestrating central nervous system (CNS) autoimmune disease pathogenesis using a conditional knockout approach.
• To investigate how CD40 expressed on specific immune cells, such as dendritic cells (DCs) and B cells, influences EAE development.

Main Methods:

• Utilized a conditional knockout strategy to delete CD40 in specific cell populations (DCs and B cells).
• Induced experimental autoimmune encephalomyelitis (EAE) using recombinant human myelin oligodendrocyte glycoprotein (rhMOG).
• Analyzed immune cell priming, T helper (Th) cell differentiation, antibody production, and immune cell infiltration into the CNS.

Main Results:

• Deletion of CD40 in either DCs or B cells significantly attenuated EAE pathogenesis.
• DC CD40 was essential for priming pathogenic Th cells and their migration to the CNS.
• B cell CD40 was critical for producing myelin oligodendrocyte glycoprotein (MOG)-specific antibodies, which were key drivers of disease.
• Passive transfer of MOG-immune serum or IgG reconstituted disease in B cell CD40-deficient mice, highlighting the role of antibodies and complement in spinal cord pathology.

Conclusions:

• CD40 signaling in both DCs and B cells orchestrates distinct but converging effector pathways in CNS autoimmune disease.
• CD40 on DCs drives T cell activation and CNS infiltration, while CD40 on B cells promotes pathogenic antibody production.
• These findings identify CD40 as a critical molecular target for therapeutic intervention in autoimmune diseases like MS.