Described herein is the development of fusion proteins useful for inducing tolerance in a subject. In particular embodiments, the tolerizing agents are useful for influence autoimmune, inflammatory, and/or allergic reactions. Example tolerizing fusion proteins contain a targeting portion (which delivers the fusion protein) and a toleragen or allergen or other antigen to which tolerance is desired in a subject. In particular examples, it is demonstrated that a pσ1 fusion protein, when administered orally, facilitates systemic and mucosal tolerance. Also described is the nasal delivery of fusion proteins, for instance for restoring immunogenicity.