Measuring the Adjuvant Activity of RNA Vaccines

mRNA has recently arisen as a promising new drug class with the potential to be applied to various therapeutic modalities, including protein replacement and vaccination against cancer and infectious diseases. Numerous approaches have been pursued to develop potent mRNA vaccines, many of them have proved to be successful and have already entered human clinical trials. RNA, especially in vitro transcribed, is extremely immunogenic as it induces innate immune responses through the activation of a variety of pattern recognition receptors. This feature of RNA is potentially beneficial for vaccine development, where antigen-encoding RNA might also function as an adjuvant to elicit potent antigen-specific T and B cell immune responses. Here, we describe the methods that can be used to evaluate the immunogenicity of RNA vaccines in vitro and in vivo.