Characterization of the antibody response in birds following infection with wild-type and attenuated strains of Eimeria tenella and Eimeria necatrix

Abstract

Live vaccines containing attenuated parasite strains are increasingly used to control chicken coccidiosis. In this paper antibody responses elicited by infections with wild-type and attenuated strains of Eimeria tenella and Eimeria necatrix were characterized by immunoblotting and ELISA with homologous and heterologous antisera. Few differences between antisera from birds infected with wild and attenuated strains of E. tenella were evident in immunoblots conducted with merozoite antigen preparations from both E. tenella strains, however the reactivity of sera raised in birds infected with the wild-type strain was noticeably more intense. In ELISAs conducted with merozoite antigen preparations, antisera from birds infected with the wild-type strains of E. tenella and E. necatrix consistently produced a significantly higher (P<0.05) antibody response than antisera from birds infected with the attenuated strains. Likewise, avidity ELISAs conducted with the E. tenella strains demonstrated that antibodies in birds infected with the wild-type strain were of significantly higher avidity (P<0.05) than antibodies in birds infected with the attenuated strain. The differences in the antibody responses are probably due to changes in the attenuated strain as a result of selection for precocious development and the less severe tissue damage and inflammation of the intestine resulting from infection with the attenuated strain.

Protective Immunity Induced by an Eimeria tenella Whole Sporozoite Vaccine Elicits Specific B-Cell Antigens

“…In order to design an effective genetically engineered vaccine, the most promising antigens were derived from the early endogenous stages of the Eimeria life cycle (sporozoites and merozoites). This correlates with the findings observed in naturally infected chickens, where these stages induce the strongest anti- Eimeria immunity [ 8 , 45 , 47 , 48 , 49 ]. Many of these antigens have critical roles in host–parasite interactions [ 3 , 5 , 14 , 16 ].…”

“…Western blot analysis allowed us to identify some antigenic differences between the sporozoites and merozoites, although the majority of the antigens seemed to be common between them. The sharing of antigens between sporozoites and merozoites has been demonstrated previously in studies with chicken and rabbit antisera [ 45 , 47 , 48 , 49 ]. As a matter of fact, most antigens with a molecular weight higher than 50 kDa seemed to be shared by these two life cycle stages [ 45 , 49 ].…”

“…In order to investigate a possible relationship between immunogenicity and the specific mass of proteins in the sporozoite and merozoite stages, immunoblots were performed with hyperimmune rabbit and chicken sera. Constantinoiu et al [ 45 , 49 ], during their studies on the kinetics and avidity of antibodies against Eimeria , observed that antibodies against E. tenella were detected from the second week and peaked at 21 days PI; however, only after the third immunization did the antisera consistently identify more polypeptides in both Eimeria asexual stages.…”

Recombinant GMA56 and ROP17 of Eimeria magna conferred protection against infection by homologous species

“…Immunized with r Em GAM56 and r Em ROP17 could induce humoral immunity in the rabbits, and the specific IgG was significantly increased. Recent research has proven that antibodies are involved in the occurrence of Eimeria infection ( 60 , 61 ), where antigen-specific antibodies inhibited adhesion to host cells ( 62 ). Moreover, it was shown that there was an excellent correlation between antibody titer and protection ( 63 ).…”

Prokaryotic expression and identification of 3-1E gene of merozoite surface antigen of Eimeria acervulina

“…Live attenuated parasite vaccines induce pronounced immune responses (Constantinoiu et al 2011) and are used to control outbreaks of infection in the field (Chapman et al 2002). Furthermore, live oocyst vaccines proved to be useful to restore ionophore sensitivity in poultry operations that contain an ionophore-resistant population of Eimeria oocysts (Jenkins et al 2010).…”