Influence of gold nanoparticles on the immune response to rift valley fever vaccine and related hepatophysiological toxicity, histological, and immunohistochemical alterations
Background: Vaccination is a very effective method of stimulating the immune response against infections. Adjuvants are employed to enhance the immune response, but they must be safe, inexpensive, and easy to use. Objective: This study aimed to evaluate gold nanoparticles as immune enhancers for rift valley fever vaccine. Methods: The rats were divided into four groups (10 each): the negative control group, rats immunized with nonadjuvanted rift valley fever vaccine and the last two rat groups immunized with rift valley fever vaccine combined with 40 μM of spherical gold nanoparticles and combined with 40 μM of rod-shaped gold nanoparticles, respectively. Results: Compared with rats receiving no treatment and rats treated with nonadjuvanted vaccine, rats treated with vaccines combined with gold nanoparticles exhibited toxic biochemical, histological and immunohistochemical changes, as shown by significant elevations in liver enzymatic markers and total bilirubin. The magnitude of the biochemical changes was dependent on the shape of the gold nanoparticles: the elevations in liver enzymatic markers and total bilirubin were greater in the group treated with spherical gold nanoparticles than in the group treated with rod-shaped gold nanoparticles. Conclusion: It can be concluded that gold nanoparticles are promising vaccine cellular and humoral immune enhancers/adjuvants via different cytokine pathways.