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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Animal Parasitic Diseases Laboratory » Research » Publications at this Location » Publication #394795

Research Project: Developing Improved Control Strategies for Avian Coccidosis

Location: Animal Parasitic Diseases Laboratory

Title: Cloning and expression of a cDNA coding for Eimeria acervulina 25 kDa protein associated with oocyst and sporocyst walls

item Jenkins, Mark
item TUCKER, MATTHEW - Florida Gulf Coast University
item Parker, Carolyn
item Obrien, Celia
item Miska, Kate

Submitted to: Veterinary Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/12/2022
Publication Date: 7/14/2022
Citation: Jenkins, M.C., Tucker, M., Parker, C.C., Obrien, C.N., Miska, K.B. 2022. Cloning and expression of a cDNA coding for Eimeria acervulina 25 kDa protein associated with oocyst and sporocyst walls. Veterinary Parasitology. 309.Article 109762.

Interpretive Summary: Avian coccidiosis is an intestinal disease of poultry caused by protozoan parasites in the genus Eimeria. The disease inflicts annual losses over 1 billion US dollars to poultry producers due to poor weight gain and inefficient feed utilization. Outbreaks of disease are prevented by incorporating anti-Eimeria drugs in poultry feed or by immunization of newly-hatched chicks with low doses of the parasite. Drug-resistance in Eimeria has become a problem, and the search is on for new drugs to prevent infection by the parasite. In the present study, a gene coding for a 25 kilodalton protein on the wall of the environmentally-resistant stage of Eimeria acervulina, namely oocysts, was characterized using cloning technology. The Ea25 gene appears to be turned on early in the developing oocyst and the encoded protein is associated with the oocyst wall. This protein elicits an immune response in Eimeria-infected chickens and thus may be an indicator of past infection. The Ea25 protein and its expression in Eimeria acervulina may represent a good target for drug development thus offering poultry companies and growers another tool in the arsenal of anti-coccidiosis therapies.

Technical Abstract: The purpose of this study was to characterize a gene named EAH 00033530 identified by RNAseq analysis of sporulating Eimeria acervulina oocysts and its encoded protein. Quantitative RT-PCR analysis revealed peak expression of EAH 00033530 mRNA early (3-6 hr) in sporulation followed by downregulation at 12-24 hr. The gene for EAH33530 was expressed in Escherichia coli as a 70 kDa polyHis fusion protein (rEAH 00033530). Antisera prepared against rEAH 00033530 protein identified in immunoblotting a native 25 kDa E. acervulina protein (Ea25) that was present in oocyst-sporocyst extracts after treatment with the reducing agent DTT. Immunofluorescence staining using anti-rEa25 localized the protein to both E. acervulina oocyst and sporocyst walls, but not to sporozoites. The protein may be produced during in vivo oocyst development because immunostaining of duodenal tissue from E. acervulina-infected chickens revealed oocyst wall expression. As observed by ELISA, rEa25 protein appears to elicit a humoral immune response in chickens infected with non-irradiated or radiation-attenuated E. acervulina oocysts.