Use of a synthetic foot-and-mouth disease virus peptide conjugated to gold nanoparticles for enhancing immunological response

Foot-and-mouth disease is an acute, highly contagious infection of domestic and wild cloven-hoofed animals, which can be transmitted to humans. In many cases, the existing vaccines are not quite effective. The purpose of this study was to test the possibility of using gold nanoparticles as an antigen carrier and an adjuvant. The immunogenic properties of gold nanoparticles were assessed by conjugating the particles to a synthetic peptide of the VP₁ capsid protein of the foot-and-mouth disease virus. The resulting conjugate (with or without the use of complete Freund’s adjuvant), a commercial vaccine, and the native peptide served to immunize guinea pigs. The titer and sensitivity of the raised antibodies were maximal for the combination comprising the nanoparticle–peptide conjugate and complete Freund’s adjuvant. Antibody biosynthesis was accompanied by increased production of proinflammatory cytokines (especially IFN-γ) and by stimulation of the respiratory activity of peritoneal macrophages. The use of gold nanoparticles as a hapten carrier enhanced the immune response even when complete Freund’s adjuvant was not used.