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Avian coccidiosis,caused by the infection of seven Eimeria spp,can cause huge economic loss in poultry industry.Eimeria maxima and Eimeria tenella are major pathogenic species as well as extreme immunogenicity which could control by vaccination of live oocysts.However,vaccination could only protects chickens from the same Eimeria species infection as there was no cross-protective immunity stimulated by vaccinated Eimeria species against other species of eimerian parasites.immune mapped protein 1(IMP 1)is a protective protein and have been used as subunit vaccine against E.maxima infection in chickens.In this study,we constructed a transgenic E.tenella line(Et/EmIMP1)expressing E.maxima IMP1(EmIMP1)for investigating the cross-immunity stimulated by the transgenic parasites in chickens.We obtained stabled transfected Et/EmIMP1 after five continues generation selections based on fluoresce activated cell sorting together with pyrimethamine,and found that EmIMP1 was surface expressed in Et/EmIMP1 sporozoites as possessing the C-terminal GPI anchoring signal of Toxoplasma gondii surface antigen 1.Furthermore,we immunized chickens with Et/EmIMP1 twice with two weeks interval and detected E.tenella and E.maxima specific IgY antibody in serum and IFN-γ secretion lymphocytes in peripheral blood mononuclear cells two weeks after each immunization.We found Et/EmIMP1 elicited E.tenella and E.maxima specific humoral immune response as well as cell-mediate immune response after booster immunization.Two weeks after second immunization,we challenged the immunized birds with E.tenella and E.maxima oocysts and analyzed the oocyst production after challenge infection.We found that the oocyst output of Et/EmIMP1 immunized birds was significantly lower than those of the wild-type E.tenella immunized birds after challenge with E.maxima whereas there was no significant difference after challenge with E.tenella.Our results indicated the transgenic E.tenella expressing EmIMP1 elicits cross-protective immunity against E.tenella and E.maxima infection in chickens and encouraging the transgenic parasites utilized as anticoccidiosis vaccine strains.