Adjuvants have been used as critical components of vaccine. They were used to stabilize the antigens and potentiate the immune responses. Dose sparing is also of interests in recent years to be applied in potential pandemic situations or to lower the costs of vaccines. With the emerging nanotechnology in many aspects including the use in biomedical applications, the application of nanomaterials as vaccine adjuvants also attracted a lot of attentions in recent years. With favorable biological properties, such as well-defined and well-formed nanoparticles, biocompatibility, biodegradability and ability to induce humoral immunity and cellular immunity simultaneously, calcium phosphate nanoparticles (CaP) have the potentials to be developed as an immune potentiator to be used as vaccine adjuvants. Here, we reviewed the basic properties of CaP and their applications as vaccine adjuvants with antigens of different modalities such as inactivated virus, protein and naked DNAs. The mechanism of the adjuvanting effects is briefly described. Further the development of CaP as vaccine adjuvants with some designed surface modification could lead to next generation vaccine adjuvants with improved immune potentiating properties and safety profiles.

Calcium phosphate; Nanoparticles; Adjuvanticity; Vaccine adjuvant; Immune potentiation