Immunoprophylactic evaluation of recombinant gametocyte 22 antigen of Eimeria tenella in broiler chickens

Gametocyte proteins are being explored as potential vaccine candidates against Eimeria sp. in chicken since they are the components of the resilient oocyst wall. The aim of this study was to investigate the immunoprophylactic efficacy of recombinant Eimeria tenella gametocyte antigen 22 (EtGam22) in chickens against homologous oocyst challenge. Broiler chicks were subcutaneously immunized individually with 100 μg of recombinant EtGam22 adjuvanted with Montanide ISA 71 VG at 7 days of age and boosted 2 weeks later. The immunized chickens were challenged individually with 1 × 10 4 sporulated oocysts of E. tenella 1 week post-booster immunization. The anti-EtGam22 IgY and serum cytokine response was measured post-immunization. The results showed that the anti-EtGam22 IgY antibody, serum IFN-γ, IL-2, TGF-β, and IL-4 levels in chickens vaccinated with recombinant protein were significantly increased post-immunization as compared to unimmunized challenged controls ( P