Submitted to: Avian Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/20/2005
Publication Date: 6/20/2005
Citation: Lillehoj, H.S., Ding, X., Quiroz, M.A., Berensee, E., Lillehoj, E.P. 2005. Resistance to intestinal coccidiosis following dna immunization with the cloned 3-1E Eimeria gene plus IL-2, IL-15, and IFN-gamma. Avian Diseases. 49:112-117. Interpretive Summary: Coccidiosis is an intestinal disease and causes severe damage to the gut of chickens. Coccidiosis costs US industry > $ 700 million annual economic losses and currently drugs and live parasites are used to control this infection. Ability to develop novel control strategy against avian coccidiosis will impact poultry industry worldwide. In this paper, ARS scientists in collaboration with Avitech company scientists developed a new strategy to induce protective immunity against coccidiosis using a recombinant coccidian vaccine. They show that embryo injection of recombinant protein is a safe, efficient, and automated method to deliver vaccine antigen. Furthermore, this is the first demonstration that in ovo vaccination of 18-day-old embryos with recombinant coccidian protein induced resistance to coccidiosis. Commercially, the advantages offered by in ovo vaccination include early immunity, reduced bird stress, precise and uniform dosaging, multiple-agent delivery, ease of handling, and reduced labor costs. The results of this study will benefit poultry industry to develop a safe next generation vaccine for avian coccidiosis.
Technical Abstract: A cloned Eimeria acervulina gene (3-1E) was used to vaccinate chickens in ovo against coccidiosis both alone and in combination with genes encoding IL-1, IL-2, IL-6, IL-8, IL-15, IL-16, IL-17, IL-18, or IFN-gamma. Vaccination efficacy was assessed by increased serum anti-3-1E antibody titers, reduced fecal oocyst shedding, and enhanced body weight gain following experimental infection with E. acervulina. When used alone, anti-3-1E antibody titers were transiently, but reproducibly, increased at 2 and 3 weeks post-hatching in a dose-dependent manner. Similarly, significantly reduced oocyst shedding and increased weight gain were observed at relatively high dose 3-1E vaccinations (> 25 g/egg). Combined immunization with the 3-1E and IL-1, IL-2, IL-15, or IFN-gamma genes induced higher serum antibody responses compared with 3-1E alone. Following parasite infection, chickens hatched from embryos given the 3-1 E gene plus the IL-2 or IL-15 genes displayed significantly reduced oocyst shedding compared with 3-1E alone while 3-1E plus IL-15 or IFN-gamma significantly increased weight gain compared with 3-1E alone. Taken together, these results indicate that in ovo immunization with a recombinant Eimeria gene in conjunction with cytokine adjuvants stimulates protective intestinal immunity against coccidiosis.