Evaluation of Aluminium Hydroxide Nanoparticles as an Efficient Adjuvant to Potentiate the Immune Response against Clostridium botulinum Serotypes C and D Toxoid Vaccines

Clostridium botulinum serotypes C and D cause botulism in livestock, a neuroparalytic disease that results in substantial economic losses. Vaccination with aluminium-based toxoid vaccines is widely used to control the spread of botulism. Aluminium-based adjuvants are preferred owing to their apparent stimulation of the immune responses to toxoid vaccines when compared to other adjuvants. The aim of our study was to evaluate aluminium hydroxide nanoparticles as a potential substitute for alhydrogel in the botulism bivalent vaccine. Botulism vaccines were formulated with either alhydrogel or nanoalum and comparative efficacy between the two formulations was conducted by evaluating the immune response in vaccinated guinea pigs. A significant increase in immunological parameters was observed, with the antibody titres higher in the serum of guinea pigs (20 IU/mL of anti-BoNT C/D) injected with nanoalum-containing vaccine than guinea pigs inoculated with the standard alhydrogel-containing vaccine (8.7 IU/mL and 10 IU/mL of anti-BoNT C and anti-BoNT D, respectively). Additionally, the nanoalum-containing vaccine demonstrated potency in a multivalent vaccine (20 IU/mL of anti-BoNT C/D), while the standard alhydrogel-containing vaccine showed a decline in anti-BoNT C (5 IU/mL) antibody titres.