EMBRYO VACCINATION AGAINST EIMERIA TENELLA AND E. ACERVULINA INFECTIONS USING RECOMBINANT PROTEINS AND CYTOKINE ADJUVANTS

Avian coccidiosis is an intestinal disease caused by protozoa of the genus Eimeria. To investigate the potential of recombinant protein vaccines to control coccidiosis, we cloned 2 Eimeria sp. genes (EtMIC2 and 3-1E), expressed and purified their encoded proteins, and determined the efficacy of in ovo immunization to protect against Eimeria infections. Immunogen-specific serum antibody titers, parasite fecal shedding, and body weight gains were measured as parameters of disease. When administered alone, the recombinant EtMIC2 gene product induced significantly higher antibody responses, lower oocyst fecal shedding, and increased weight gains compared with nonvaccinated controls following infection with E. tenella. Combined embryo immunization with the EtMIC2 protein plus chicken cytokine or chemokine genes demonstrated that all 3 parameters of vaccination were improved compared with those of EtMIC2 alone. In particular, covaccination with EtMIC2 plus interleukin (IL)-8, IL-16, transforming growth factor-β...