Immune modulation and enhancement of immunity by the use of an adjuvanted solvent (Hipramune®T) in a live coccidiosis vaccine for breeders and layers(Evalon®)

Objectives: In order to study the mechanisms by which an adjuvant could modulate the immune mechanisms that are triggered in the host after coccidiosis vaccination, a study was performed in which birds were vaccinated with a live attenuated coccidiosis vaccine (EVALON®) at one day of age, with or without a selected adjuvant, to study important markers of Th۱ and Th۲ responses. Materials and methods: EVALON® is a live coccidiosis vaccine against avian coccidiosis. It is composed of five attenuated strains: Eimeria acervulina, E. brunetti, E. maxima, E. necatrix and E. tenella. Eimeria parasites have a complex life cycle that trigger a response by the host’s immune system. However, they also elude the immune system, producing chemokines that can slow orinhibit the host’s immune response. In this study, four treatment subgroups received EVALON®, EVALON® in combination with HIPRAMUNE®T or phosphate buffered solution (control group). Five birds from each subgroup were used to obtain intestinal lymphocytes from the mucosa and Peyer’s patches at different time points post-vaccination (۷, ۲۳ and ۴۳ days). The lymphocytes were then incubated in appropriate medium and stimulated overnight with Eimeria whole antigen. Later, the lymphocytes were fixed and stained using monoclonal antibodies marked with fluorescein and studied with flow cytometry to detect lymphocytes producing IL-۲, IFN-Ƴ, IL-۴ and IL-۱۰. Results and discussion: The results obtained in the first experiment indicated that HIPRAMUNE®T is able to increase the level of Th۱ cytokines, as indicated by the results obtained for IL-۲ (significantly higher levels were detected at days ۲۳ and ۴۳ for the mucosa and at day ۴۳ for the Peyer’s patches) and IFN-Ƴ (significantly higher levels were detected at days ۷ and ۲۳ for the mucosa and at days ۲۳ and ۴۳ for the Peyer’s patches). By contrast, the levels of IL-۴ and IL-۱۰ at days ۲۳ and ۴۳ were equal or lower in the EVALON® with HIPRAMUNE®T group compared tothe EVALON® alone. These results, combined with the results recorded for IL-۲ and IFN-Ƴ, confirm HIPRAMUNE®T’s ability to stimulate a cellular immune response. Therefore, it is hypothesised that EVALON® administered together with HIPRAMUNE®T is able to polarise the immune response towards a Th۱ response with more intensity, as the study indicates, than the live vaccine without the adjuvant. In vaccines designed for layers and breeders, it is of paramount importance to provide extended protection throughout the life cycle.

کلیدواژه ها:

coccidiosis ، immune modulation ، adjuvant ، vaccine ، attenuation