Cloning of Etp28 gene of Eimeria tenella (Guangdong Strain) sporozoites and its expression in Baculovirus expression system

A refractile body antigen Etp28 gene of Eimeria tenella (Guangdong Strain) sporozoites was cloned by PCR from the synthesized first strand cDNA. It has a high homology with the previously reported Etp28 gene of Merck Strain LS18. The gene was expressed through standard procedures in the modified Autographa californica nuclear polyhedrosis virus (AcMNPV-OCC-) expression system and large amount of heterologous fusion protein (GST-6 X His-Etp28) was obtained. The expression product was about 21. 3% of the total cellular protein of an infected cell and corresponding to approximately 0.42 mg of recombinant protein per 10(6) cells. And the immunoprotective trial showed that this candidate for recombinant vaccine conferred partial protection against chicken coccidiosis.