Oral immunization of Birds Against Recombinant Eimera Antigens: An Approach for Vaccinating Poultry Birds Against Coccidiosis

Coccidiosis is an economically important disease worldwide and is caused by the protozoan of genus Eimeria. In the present study we report transient expression of two coccidial antigens EtMIC1 and EtMIC2 as His₆-tagged fusion proteins in plants. Fourteen day old chickens were immunized orally with formulation containing purified recombinant antigens in combination with mucosal adjuvants like Cholera toxin-B and mineral oil adjuvant. Immunogenicity of the two formulations were evaluated in birds by estimating humoral as well as cell mediate immune response. Birds immunized with both antigens in combination with CTB as adjuvant has shown a maximum of 920 (±500) serum antibody titer against EtMIC2. The combination of oil adjuvant with antigens has shown a maximum of 720 (±580) serum antibody titer against EtMIC2. There was an average increase of about 250 pg/ml and 200 pg/ml of IFN-γ levels was measured from splenocytes induced with EtMIC2 protein. Our results indicate that the combination of plant expressed antigens adjuvanted with CTB had enhanced humoral and as well as CMI immune response in the immunized birds. Also, our results suggest that EtMIC2 protein is better immunogen compared with EtMIC1.