Table 2.
The main types and functions of immune adjuvants.
| Type | Adjuvant | Function | References |
|---|---|---|---|
| Delivery systems | Calcium phosphate | Biodegradable, low toxicity, and high loading capacity | (92) |
| Aluminum salts | Enhance humoral immunity, and prolonged the intratumoral retention time of drugs | (93) | |
| Emulsions | Form a depot at the injection site, induces inflammation, and gradually release the antigen | (94) | |
| Liposomes | Similar to the structure of biofilm, deliver drugs or antigens into targeted cells, and have high bioavailability | (95–97) | |
| Metal | Enhance immunogenicity and cellular uptake | (80, 98) | |
| Non-metallic material | High cargo-carrying capacity and unique physicochemical properties can be combined with physical therapy | (99, 100) | |
| Biogenic nanomaterials | Induction of sufficient anti-tumor responses without causing significant adverse effects | (17, 101–103) | |
| Immunostimulants | TLRa | Detecting PAMPs and responding to them by activating innate and adaptive immune pathways | (83, 95, 98, 104–107) |
| Cytokines | Promote DCs maturation and subsequently enhance the generation of antigen-specific CD8+ T cell | (93, 108) | |
| Chemokines | Regulate lymphocyte development, initiate and execute effector functions, and enhance the capacity for protective immunity | (109, 110) | |
| STING agonists | Ensure the production of type I interferon to assist in regulating the immune activity | (111) | |
| Carbohydrate-based adjuvants | Transfer information and stimulate humoral and cellular immunity | (94, 95, 98, 112) |