|Lee, Kyung woo|
|Park, Myeong seon|
Submitted to: Vaccine
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/10/2010
Publication Date: 6/20/2010
Citation: Jang, S.I., Lillehoj, H.S., Lee, S.H., Lee, K.W., Park, M.S., Cha, S.R., Lillehoj, E.P., Subramanian, B.M., Sriraman, R., Srinivasan, V.A. 2010. Eimeria maxima recombinant Gam82 gametocyte antigen vaccine protects against coccidiosis and augments humoral and cell-mediated immunity. Vaccine. 28(17):2980-2985. Interpretive Summary: Avian coccidiosis is caused by several different species of Eimeria which invade the intestinal epithelium causing reduced feed conversion efficiency and decreased body weight gain. Other than live parasite vaccines, there is no effective non-infectious vaccine . With increasing demands for high-protein meats and heightened consumer concerns over the use of antibiotics in poultry production, the development of alternative strategies against avian coccidiosis assumes a high priority. ARS scientists in collaboration with Indian Immunology Institute studied the effect of recombinant parasite vaccine using an antigen from the sexual stage of Eimeria life cycle. This paper reports that an 82 kilodalton protein of Eimeria gametocytes, Gam82, showed a significant protection against avian coccidiosis when used as an immunogen in young broiler chickens. Gam82, the 82 kDa tyrosine-rich sexual stage glycoprotein of E. maxima, has been implicated in oocyst wall formation and this study showed that this gametocyte protein promotes cell-mediated and transmission-blocking immunity against subsequent parasite infection. These results suggest that host immunity to Gam82 may play an important role in impeding host transmission of Eimeria infection by blocking the parasite life cycle at the fecal shedding stage. The findings from this work will provide critical information for the development of recombinant vaccine against avian coccidiosis for poultry industry.
Technical Abstract: Intestinal infection with Eimeria, the etiologic agent of avian coccidiosis, stimulates protective immunity to subsequent colonization by the homologous parasite, whilst cross-protection against heterologous species is poor. As a first step toward the development of a broad specificity Eimeria vaccine, this study was designed to assess a purified recombinant protein from E. maxima gametocytes (Gam82) in stimulating immunity against experimental infection with live parasites. Following Gam82 intramuscular immunization and oral parasite challenge, body weight gain, fecal oocyst output, lesion scores, serum antibody response, and cytokine production were assessed to evaluate vaccination efficacy. Animals vaccinated with Gam82 and challenged with E. maxima showed lower oocyst shedding and reduced intestinal pathology compared with non-vaccinated and parasite-challenged animals. Gam82 vaccination also stimulated the production of antigen-specific serum antibodies and induced greater levels of IL-2 and IL-15 mRNAs compared with non-vaccinated controls. These results demonstrate that the Gam82 recombinant protein protects against E. maxima and augments humoral and cell-mediated immunity.