Adjuvant effects of IL-1β, IL-2, IL-8, IL-15, IFN-α, IFN-γTGF-β4 and lymphotactin on DNA vaccination against Eimeria acervulina

Abstract

Eight chicken cytokine genes ( IL-1β, IL-2, IL-8, IL-15, IFN-α, IFN-γ, TGF-β4, lymphotactin) were evaluated for their adjuvant effect on a suboptimal dose of an Eimeria DNA vaccine carrying the 3-1E parasite gene (pcDNA3-1E). Chickens were given two subcutaneous injections with 50 μg of the pcDNA3-1E vaccine plus a cytokine expression plasmid 2 weeks apart and challenged with Eimeria acervulina 1 week later. IFN-α (1 μg) or 10 μg of lymphotactin expressing plasmids, when given simultaneously with the pcDNA3-1E vaccine, significantly protected against body weight loss induced by E. acervulina. Parasite replication was significantly reduced in chickens given the pcDNA3-1E vaccine along with 10 μg of the IL-8, lymphotactin, IFN-γ, IL-15, TGF-β4, or IL-1β plasmids compared with chickens given the pcDNA3-1E vaccine alone. Flow cytometric analysis of duodenum intraepithelial lymphocytes showed chickens that received the pcDNA3-1E vaccine simultaneously with the IL-8 or IL-15 genes had significantly increased CD3 + cells compared with vaccination using pcDNA3-1E alone or in combination with the other cytokine genes tested. These results indicate that the type and the dose of cytokine genes injected into chickens influence the quality of the local immune response to DNA vaccination against coccidiosis.