Comparative Serum Immune Responses to Bacterial Ghost and Liposomal APEC Vaccine Formulations in Broiler Chickens

Abstract

This study compared the preliminary serum immune-marker responses induced by two vaccine preparations against avian pathogenic Escherichia coli (APEC) in broiler chickens: a bacterial ghost preparation (BGs) and a liposome-based preparation (LIPO). Serum IL-4, IL-10, IL-12, IL-1β, IFN-γ, and total IgY were measured by ELISA to evaluate humoral, cellular, and inflammatory responses relative to a negative control group. Overall differences among the three groups were statistically significant for all measured markers (p < 0.0001). Direct comparison of the vaccinated groups showed significantly higher IL-10, IL-1β, and total IgY concentrations in the BGs group, whereas IL-4 was significantly higher in the LIPO group. IL-12 and IFN-γ did not differ significantly between the two vaccinated groups. These findings indicate that the two preparations generated distinct preliminary serum immune-marker profiles. Because protective efficacy was not evaluated in an APEC challenge model, further studies are required before either preparation can be considered an effective vaccine against colibacillosis.