Disclosed herein are compositions and methods for inducing, promoting, or enhancing an immune response in a subject. For example, the disclosed compositions and methods can be used prophylactically to prevent viral/microbial infections or therapeutically to treat acute infections. In some embodiments, the disclosed method involves administering to the subject a composition comprising in vitro transcribed (IVT) RNA comprising short interspersed nuclear elements (SINEs), such as Alu repeats. In some embodiments, the disclosed compositions and methods can be used to induce, promote, or enhance any immune response in a subject, including an anti-viral, anti-microbial, anti-fungal, or anti-parasite response. In some embodiments, the disclosed compositions can be administered to any mucosal barrier, such as lungs or intestines, e.g. to enhance an innate immune response against a virus or pathogen.