Aluminum phosphate (AlPO4)

Aluminum phosphate is an inorganic salt widely utilized as a vaccine adjuvant to enhance the immunogenicity of vaccines (PubChem CID 24651). It is not a traditional therapeutic target like a receptor or enzyme; rather, it is a pharmaceutical agent that modulates the immune system to improve vaccine efficacy. The surface of aluminum phosphate is critical because it adsorbs protein antigens via electrostatic forces and ligand exchange, facilitating a depot effect that allows for the slow release of antigens at the injection site (PMID: 12144774). Biologically, it promotes the recruitment of antigen-presenting cells and activates the NLRP3 inflammasome, which is essential for the secretion of pro-inflammatory cytokines like IL-1β (PMID: 18463634). This mechanism typically induces a Th2-biased immune response, characterized by the production of IgG1 antibodies (PMID: 19002170). It is a standard component in many pediatric and adult vaccines, including those for Hepatitis B, Diphtheria, Tetanus, and Pertussis (CDC, Adjuvants in Vaccines).

Other names

Aluminum phosphate adjuvantAdju-PhosColloidal aluminum phosphatePhosphoric acid, aluminum salt

Adsorption of antigens to the adjuvant surface to create a depot for slow release, enhancement of antigen uptake by dendritic cells, and activation of the NLRP3 inflammasome to stimulate an immune response (PMID: 18463634).