Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 1, 2005
Publication Date: July 5, 2005
Citation: Lillehoj, H.S., Ding, X., Dalloul, R.A., Sato, T., Yasuda, A., Kukkegih, E.P. 2005. Embryo vaccination against Eimeria tenella and E. acervulina infections using recombinant proteins and cytokine adjuvants. Journal of Parasitology. 91:666-673.
Interpretive Summary: Eimeria is an important protozoan pathogens of poultry belonging to the phylum Apicomplexa. Seven species of Eimeria are the etiologic agents of avian coccidiosis, an intestinal disease impairing the feed utilization and growth of infected animals. Although anti-coccidial drugs in poultry feed are good preventatives and convenient for large-scale use, alternative control strategies are needed due to the emergence of drug resistant parasites in commercial production settings. In this paper, ARS scientists in collaboration with a scientist at Zeon company and University of Maryland describe novel molecular and genomics strategies to investigate host response to coccidian parasites. For example, several potential novel coccidian proteins which elicit protective immunity have been identified using a new molecular genomics technology. Furthermore, these scientists describe new ways to inject recombinant coccidia proteins into 18-day-old developing embryos using a commercial in ovo injector. They also demonstrate the effectiveness of injecting DNA vaccine to induce protection against coccidiosis. These results will enhance our ability to develop novel vaccine against avian coccidiosis.
An Eimeria tenella microneme 2 (EtMIC2) gene and the encoded protein were evaluated as a potential vaccine against avian coccidiosis. In ovo vaccination with the EtMIC2 gene increased anti-EtMIC2 antibody titers at days 11 and 17 days post-hatching. In addition, vaccinated animals developed protective immunity against infection by E. tenella as assessed by significantly increased body weight gain and decreased fecal oocyst shedding compared with non-vaccinated controls. Vaccination with the EtMIC2 gene also led to protective immunity against infection by E. acervulina, but not E. maxima. Combined in ovo DNA vaccination plus post-hatch boosting with EtMIC2 DNA or protein did not improve antibody titers or protective immunity beyond that achieved with in ovo vaccination alone. These results provide evidence that in ovo immunization with EtMIC2 gene stimulates protective intestinal immunity against coccidiosis.