Provided are modified microorganisms, such as live recombinant commensal bacteria, that express a heterologous antigen, and methods of using the modified microorganisms to induce an antigen-specific immune response to the heterologous antigen. The modified microorganism can be used to induce a regulatory T cell immune response to the heterologous antigen to treat an autoimmune disease in a subject in need thereof, or can be used to induce an effector T cell immune response to the heterologous antigen to treat a proliferative disease in a subject in need thereof.

This disclosure provides compositions and methods for stimulating the innate immune response in a subject with agents capable of stimulating an innate immune response in a subject upon administration to the subject (e.g., damage-associated molecular patterns (DAMPs) and pathogen-associated molecular patterns (PAMPs)). In particular, the present invention is directed to compositions of DAMPs/PAMPs and metals ions, as well as systems and methods utilizing such nanoparticles (e.g., in diagnostic and/or therapeutic settings).