Antigen-Specific Binding of Multivalent Soluble Antigen Arrays Induces Receptor Clustering and Impedes B Cell Receptor Mediated Signaling

Brittany L. Hartwell, Francisco J. Martinez-Becerra, Jun Chen, Heather Shinogle, Michelle Sarnowski, David S. Moore, Cory Berkland

Research output: Contribution to journalArticlepeer-review

Abstract

A pressing need exists for autoimmune disease therapies that act in an antigen-specific manner while avoiding global immunosuppression. Multivalent soluble antigen arrays (SAgAPLP:LABL), designed to induce tolerance to a specific multiple sclerosis autoantigen, consist of a flexible hyaluronic acid (HA) polymer backbone cografted with multiple copies of autoantigen peptide (PLP) and cell adhesion inhibitor peptide (LABL). Previous in vivo studies revealed copresentation of both signals on HA was necessary for therapeutic efficacy. To elucidate therapeutic cellular mechanisms, in vitro studies were performed in a model B cell system to evaluate binding and specificity. Compared to HA and HA arrays containing only grafted PLP or LABL, SAgAPLP:LABL displaying both PLP and LABL exhibited greatly enhanced B cell binding. Furthermore, the binding avidity of SAgAPLP:LABL was primarily driven by the PLP antigen, determined via flow cytometry competitive dissociation studies. Fluorescence microscopy showed SAgAPLP:LABL induced mature receptor clustering that was faster than other HA arrays with only one type of grafted peptide. SAgAPLP:LABL molecules also reduced and inhibited IgM-stimulated signaling as discerned by a calcium flux assay. The molecular mechanisms of enhanced antigen-specific binding, mature receptor clustering, and dampened signaling observed in B cells may contribute to SAgAPLP:LABL therapeutic efficacy.

Original languageEnglish (US)
Pages (from-to)710-722
Number of pages13
JournalBiomacromolecules
Volume17
Issue number3
DOIs
StatePublished - Mar 14 2016
Externally publishedYes

Bibliographical note

Funding Information:
We gratefully acknowledge support from the National Institute of Allergy and Infectious Diseases at the National Institutes of Health (R56 AI091996), Kansas IDeA Network of Biomedical Research Excellence, and the Madison and Lila Self Graduate Fellowship at the University of Kansas. Additionally, we thank the Microscopy and Analytical Imaging Core Lab and the Kansas Vaccine Institute at the University of Kansas for their collaboration and instrument use.

Publisher Copyright:
© 2016 American Chemical Society.

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