Antigen-specific suppression of inflammatory arthritis using liposomes

Existing therapies for rheumatoid arthritis and other autoimmune diseases are not Ag specific, which increases the likelihood of systemic toxicity. We show that egg phosphatidylcholine liposomes loaded with Ag (OVA or methylated BSA) and a lipophilic NF-κB inhibitor (curcumin, quercetin, or Bay11-7082) suppress preexisting immune responses in an Ag-specific manner. We injected loaded liposomes into mice primed with Ag or into mice suffering from Ag-induced inflammatory arthritis. The liposomes targeted APCs in situ, suppressing the cells' responsiveness to NF-κB and inducing Ag-specific FoxP3⁺ regulatory T cells. This regulatory mechanism suppressed effector T cell responses and the clinical signs of fullblown Ag-induced arthritis. Thus, liposomes encapsulate Ags and NF-κB inhibitors stably and efficiently and could be readily adapted to deliver Ags and inhibitors for Ag-specific suppression of other autoimmune and allergic diseases.