Aluminium Nanoparticles as Efficient Adjuvants Compared to Their Microparticle Counterparts: Current Progress and Perspectives

Aluminium (Al) compounds are used as adjuvants in human and veterinary prophylactic vaccines due to their improved tolerability compared to other adjuvants. These Al-based adjuvants form microparticles (MPs) of heterogeneous sizes ranging from similar to 0.5 to 10 mu m and generally induce type 2 (Th2)-biased immune responses. However, recent literature indicates that moving from micron dimension particles toward the nanoscale can modify the adjuvanticity of Al towards type 1 (Th1) responses, which can potentially be exploited for the development of vaccines for which Th1 immunity is crucial. Specifically, in the context of cancer treatments, Al nanoparticles (Al-NPs) can induce a more balanced (Th1/Th2), robust, and durable immune response associated with an increased number of cytotoxic T cells compared to Al-MPs, which are more favourable for stimulating an oncolytic response. In this review, we compare the adjuvant properties of Al-NPs to those of Al-MPs in the context of infectious disease vaccines and cancer immunotherapy and provide perspectives for future research.

Automated summary

Aluminium compounds are commonly used as adjuvants in vaccines due to their improved tolerability. Recent studies have shown that moving from microparticles to nanoparticles can modify the immune responses induced by aluminium-based adjuvants. This review compares the adjuvant properties of aluminium nanoparticles and microparticles in the context of infectious disease vaccines and cancer immunotherapy.