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-beta4, or
lymphotactin significantly decreased oocyst shedding and improved
weight gains beyond those achieved by EtMIC2 alone. Finally, individual vaccination with either EtMIC2 or 3-1E stimulated protection against
infection by the heterologous parasite E. acervulina. Taken together, these results indicate that in ovo vaccination with the EtMIC2
protein plus
cytokine/
chemokine genes may be an effective method to control
coccidiosis.