Molecular characterization and immune protection by cystathionine β‐synthase from Eimeria tenella

Abstract

Eimeria tenella is an obligate intracellular apicomplexan parasite that causes avian coccidiosis and leads to severe economic losses in the global poultry industry. Cystathionine β‐synthase (CBS) and cystathionine γ‐lyase (CGL) act together to generate H2S in the reverse transsulfuration pathway. In this study, E. tenella Cystathionine β‐synthase (EtCBS) was cloned using rapid amplification of cDNA 5′‐ends (5'RACE) and characterized, and its immunoprotective effects were evaluated. The recombinant EtCBS protein (rEtCBS) was expressed and successfully recognized by anti‐sporozoites (Spz) protein rabbit serum. EtCBS mRNA levels were highest in Spz by qPCR, and the protein expression levels were higher in unsporulated oocysts (UO) than in other stages by Western blot. Indirect immunofluorescence showed that EtCBS protein was found on the surface of Spz and second‐generation merozoites (Mrz). The invasion inhibition assays showed that rabbit anti‐rEtCBS polyclonal antibodies effectively inhibited parasite invasion host cells. Chickens immunized with rEtCBS protein showed prominently increased weight gains and decreased oocyst output compared to nonimmunized and infected control group. The results suggest that EtCBS could be a potential vaccine candidate against E. tenella.

Vaccination Against Poultry Parasites

“…There is also ample evidence that a degree of passive immunity can be transferred with antibodies, either by maternal antibodies (22,23), feeding hyperimmune egg yolk powder (24,25), or parenteral transfer of convalescent sera (26). Host cell invasion of sporozoites can be reduced in vitro by antisera against recombinant Eimeria proteins (27,28,29,30). Hormonally and chemically bursectomized chickens are more susceptible to coccidia infections, but are still able to mount an effective immune response (31,32).…”