Autoimmune diseases are heterogeneous pathologies characterized by a breakdown of immunological tolerance to self, resulting in a chronic and aberrant immune response to self-antigens. The scope... Show moreAutoimmune diseases are heterogeneous pathologies characterized by a breakdown of immunological tolerance to self, resulting in a chronic and aberrant immune response to self-antigens. The scope and extent of affected tissues can vary greatly per autoimmune disease and can involve multiple organs and tissue types. The patho-genesis of most autoimmune diseases remains unknown but it is widely accepted that a complex interplay be-tween (autoreactive) B and T cells in the context of breached immunological tolerance drives autoimmune pathology. The importance of B cells in autoimmune disease is exemplified by the successful use of B cell tar-geting therapies in the clinic. For example, Rituximab, a depleting anti-CD20 antibody, has shown favorable results in reducing the signs and symptoms of multiple autoimmune diseases, including Rheumatoid Arthritis, Anti-Neutrophil Cytoplasmic Antibody associated vasculitis and Multiple Sclerosis. However, Rituximab depletes the entire B cell repertoire, leaving patients susceptible to (latent) infections. Therefore, multiple ways to target autoreactive cells in an antigen-specific manner are currently under investigation. In this review, we will lay out the current state of antigen-specific B cell inhibiting or depleting therapies in the context of autoimmune diseases. Show less
Multiple Sclerosis is a degenerative disease of the central nervous system (CNS), involving autoimmunity against myelin, resulting in demyelination and paralysis. Antigen-specific immunotherapy may... Show moreMultiple Sclerosis is a degenerative disease of the central nervous system (CNS), involving autoimmunity against myelin, resulting in demyelination and paralysis. Antigen-specific immunotherapy may reduce this pathological autoimmunity, without disturbing normal immune function. This could be achieved by targeting of myelin antigens towards C-type lectin receptors (CLR) that recognize carbohydrate structures and are expressed on immune cells, because targeting of CLR under steady state conditions can suppress immunity in an antigen-specific way. In vitro studies showed that mannosylation of peptides results in internalization via the mannose receptor. In this study we observed, that immunization with mannosylated peptide does not induce disease in EAE, a model for Multiple Sclerosis. Instead, antigen-specific tolerance was induced; CNS inflammation was absent and DTH responses were impaired. Using transfer of TCR transgenic T cells in vivo we visualized that immunization with mannosylated peptide enhanced antigen presentation and induced vigorous expansion of T cells. However, T cells showed reduced blast formation and did not transfer EAE, despite normal production of inflammatory cytokines and chemokines. Lymphocytes accumulated in the lymph node of tolerized mice, which was counteracted by injection of Pertussis Toxin. Established EAE or ongoing DTH responses were ameliorated after mannosylated peptide treatment. In conclusion, mannosylated myelin peptide induced tolerance to EAE due to incomplete differentiation of encephalitogenic T cells and can be used to treat ongoing autoimmunity. Therefore, mannosylated antigens may represent a novel therapeutic approach for antigen-specific modulation of autoreactive T cells in vivo. Show less
