Multivalent scaffolds that carry multiple molecules with immunophenotyping or immunomodulatory properties areinvaluable tools for studying and modulating specific functions ofhuman immune responses... Show moreMultivalent scaffolds that carry multiple molecules with immunophenotyping or immunomodulatory properties areinvaluable tools for studying and modulating specific functions ofhuman immune responses. So far, streptavidin-biotin-basedtetramers have been widely used for B-cell immunophenotypingpurposes. However, the utility of these tetramers is limited by theirtetravalency, the inherent immunogenicity of streptavidin (abacterial protein that can potentially be recognized by B cells),and the limited feasibility to functionalize these reagents. This has rendered tetramers suboptimal for studying rare, in particular,antigen-specific B-cell populations in the context of clinical applications. Here, we used polyisocyanopeptides (PICs), multivalentpolymeric scaffolds functionalized with around 50 peptide antigens, to detect autoreactive B cells in the peripheral blood of patientswith rheumatoid arthritis. To explore the potential immunomodulatory functionalities, we functionalized PICs with autoantigenicpeptides and a trisaccharide CD22 ligand to inhibit autoreactive B-cell activation through interference with the B-cell receptoractivation pathway, as evidenced by reduced phospho-Syk expression upon PIC binding. Given the possibilities to functionalizePICs, our data demonstrate that the modular and versatile character of PIC scaffolds makes them promising candidates for futureclinical applications in B-cell-mediated diseases Show less
