Hyaluronic Acid Graft Polymers Displaying Peptide Antigen Modulate Dendritic Cell Response in Vitro

Abstract

A novel oxime grafting scheme was utilized to conjugate an ICAM-1 ligand (LABL), a cellular antigen ovalbumin (OVA), or both peptides simultaneously to hyaluronic acid (HA). Samples of HA only and the various peptide grafted HA were found to bind to dendritic cells (DCs). HA with grafted LABL and OVA showed the greatest binding to DCs. Dendritic cells treated with HA, HA with grafted LABL, or HA with grafted LABL and OVA, significantly suppressed T cell and DC conjugate formation, T cell proliferation and reduced proinflammatory cytokine production compared to untreated cells. These results suggest that HA serves as an effective backbone for multivalent ligand presentation for inhibiting T cell response to antigen presentation. In addition, multivalent display of both antigen and an ICAM-1inhibitor (LABL) may enhance binding to DCs and could potentially disrupt cellular signaling leading to autoimmunity.

Co-Delivery of Autoantigen and B7 Pathway Modulators Suppresses Experimental Autoimmune Encephalomyelitis

“…The molecular weight of each SAgA was determined using a Shimadzu HPLC system with a refractive index detector previously described (15). Samples were separated by utilizing a tandem column setup of an Agilent PL aquagel-OH 60 and Agilent PL aquagel-OH 40 column in series.…”

“…SAgAs targeting the B7 pathway were created by co-grafting to hyaluronic acid polymers (HA) both autoantigen (PLP 139-151 ) and B7-binding peptides (B7AP, CD80-CAP, or sF2) as previously reported (15,24,25). For a positive control, an ICAM-1-targeted SAgA (SAgA PLP:LABL ) was created containing autoantigen (PLP [139][140][141][142][143][144][145][146][147][148][149][150][151] ) and the cell adhesion peptide LABL derived from leukocyte function associated antigen-1 (LFA-1), which has previously shown efficacy in EAE (24,25).…”

“…Co-delivery of both antigen and a co-stimulatory context signal activates an antigen-specific adaptive immune response, whereas delivery of a co-inhibitory context signal or absence of either signal can render an anergic response (i.e., no response) and is believed to be a main mechanism of peripheral immune tolerance (8,9,13). Thus, co-delivery of a synthetic co-inhibitory context signal and autoantigen may be a suitable pharmacological template to restore immune tolerance and treat various autoimmune disorders (13)(14)(15)(16).…”

“…We grafted to hyaluronic acid both a myelin sheath antigenic peptide (PLP [139][140][141][142][143][144][145][146][147][148][149][150][151] ) and peptides capable of binding B7 signaling pathway surface receptors by following previously reported procedures (15,24,25). The resulting soluble antigen arrays (SAgAs) act as a carrier to co-deliver multiple copies of the autoantigen and a peptide from the B7 pathway.…”

Structure, Size, and Solubility of Antigen Arrays Determines Efficacy in Experimental Autoimmune Encephalomyelitis

“…The SAgAs showed the appropriate shift in retention time indicating an increase in MW equal to that of the number of grafted peptides determined by HPLC. The combination of the HPLC and GPC data also showed the desired 1:1 ratio of PLP and LABL peptides was achieved MW relative to pulluan standards was calculated as previously reported (Table I) (26,38).…”