Identification and molecular characterization of a novel antigen of Eimeria acervulina

► Construction of cDNA expression library of Eimeria acervulina sporozoites. ► A new gene cSZ-JN1 was selected by three rounds of screening. ► cSZ-JN1 could express in the sporozoite and merozoite stages of E. acervulina. ► Recombinant cSZ-JN1 protein and the DNA vaccine carrying cSZ-JN1 gene were able to induce partial protection against homologous challenge in chickens.