Autoantigen Tetramer Silences Autoreactive B Cell Populations.

Many autoimmune therapies focus on immune suppression to reduce symptom severity and halt disease progression; however, currently approved treatments lack specificity for the autoantigen and rely on more global immune suppression. Multivalent antigen arrays can disarm pathogenic autoimmune B cell populations that specifically recognize the antigen of interest via their B cell receptor (BCR). Disarmament may be achieved by BCR engagement, cross-linking, and sustained receptor occupancy as a result of multivalent, high avidity BCR binding. To engage and explore this mechanism, a tetramer display of the encephalogenic proteolipid peptide (PLP), referred to as 4-arm PLP, was synthesized by copper-catalyzed azide-alkyne cycloaddition chemistry. Subcutaneous administration of 4-arm PLP completely ameliorated symptoms of paralysis in a mouse model of multiple sclerosis known as experimental autoimmune encephalomyelitis. Competitive binding of 4-arm PLP to PLP-specific IgG in the mouse serum demonstrated the enhanced avidity associated with the multivalent array compared to the free peptide. Furthermore, key PLP-reactive B cells were depleted following 4-arm PLP treatment, resulting in significant reduction of proinflammatory cytokines. Together, these data demonstrate the potential of 4-arm PLP to silence autoreactive B cell populations and limit the downstream activation of effector cells.