Cyclic guanosine monophosphate-adenosine monophosphate (cGAMP): a novel vaccine adjuvant

Abstract

Aluminum salts are the most popular adjuvants applied in human vaccines currently. However, they can′t achieve satisfying results in the development of novel vaccines because of the cellular immune responses induced by them are weak and their adjuvant activities for some novel vaccines are poor, especially in vaccination against peptide antigens with small molecular weight. cGAMP (cyclic guanosine monophosphate-adenosine monophosphate) has recently been known as a mammalian second messenger, which plays an important role in the innate immune signaling pathway and is capable of boosting the immunogenicity of vaccines, activating antigen-presenting cells and enhancing specific T cell responses. cGAMP is expected to become a new generation of vaccine adjuvants against infectious diseases and cancer. In this review, we summarize the application and current situation of vaccine adjuvants, describe the discovery of cGAMP and its mechanism as a vaccine adjuvant, and focus on the advances in using cGAMP in the fields of vaccination against infectious diseases, intradermal immunization and tumor immunotherapy. Finally, it is also pointed out that cGAMP, as a novel vaccine adjuvant, will have a broad prospect of application in areas such as anti-tumor, anti-virus, anti-inflammatory and vaccines. Key words: cGAMP; Vaccine; Adjuvant