Identification of highly cross-reactive immunogens in Eimeria tenella sporozoites.

Avian coccidiosis significantly impairs intestinal health in chickens and remains a major threat to the poultry industry worldwide. Frequent co-infections with three Eimeria species, i.e., Eimeria tenella, E. necatrix, and E. maxima, present challenges for effective vaccine development. Here, we first used two-dimensional gel electrophoresis and silver staining to identify 650 E. tenella sporozoite proteins and then detected 18 cross-reactive immunogens based on Western blotting and proteomic analysis. These immunogens were consistently recognized by hyperimmune sera raised against three Eimeria species of interest. Bioinformatics analysis revealed that these proteins encompass enzymes, motility-related proteins, nuclear factors, and translation machinery, with amino acid sequence identities ranging from 71.1%-98.8% with E. necatrix and 37.9%-87.5% with E. maxima homologues. Seven of these proteins show potential non-classical secretion, and four have transmembrane domains. Overall, these findings point to multiple cross-reactive immunogens as potential candidates for multivalent coccidiosis vaccines.