Summary: Furthermore, we investigated the capacity of silicone oil microdroplets to induce antibody responses against a model protein known to form agglomerates and undergo structural perturbations in the presence of silicone oil microdroplets, hen egg lysozyme (HEL). Silicone oil microdroplets elicited robust antibody responses against HEL in non-transgenic mice where HEL was recognized as foreign, but silicone oil microdroplets did not promote a break in tolerance in immune tolerant transgenic mice. Thus, structural perturbations in proteins adsorbed to silicone oil microdroplets may not increase the immunogenicity of proteins.