Molecular characterization and protective efficacy of a new conserved hypothetical protein ofEimeria tenella

Abstract

Eimeria tenella is an obligate intracellular parasite that actively invades cecal epithelial cells of chickens. This parasite encodes a genome of more than 8000 genes. However, more than 70% of the gene models for this species are currently annotated as hypothetical proteins. In this study, a conserved hypothetical protein gene of E. tenella, designated EtCHP18905, was cloned and identified, and its immune protective effects were evaluated. The open reading frame of EtCHP18905 was 1053bp and encoded a protein of 350 amino acids with a molecular weight of 38.7kDa. The recombinant EtCHP18905 protein (rEtCHP18905) was expressed in E. coli. Using western blot, the recombinant protein was successfully recognized by anti GST-Tag monoclonal antibody and anti-sporozoites protein rabbit serum. Real-time quantitative PCR analysis revealed that the EtCHP18905 mRNA levels were higher in sporozoites than in unsporulated oocysts, sporulated oocysts and second-generation merozoites. Western blot analysis showed that EtCHP18905 protein expression levels were lower in sporozoites than in other stages. Immunofluorescence analysis indicated that the EtCHP18905 protein was located on the surface of sporozoites and second-generation merozoites. Inhibition experiments showed that the ability of sporozoites to invade host cells was significantly decreased after treatment with the anti-rEtCHP18905 polyclonal antibody. Vaccination with rEtCHP18905 protein was able to significantly decrease mean lesion scores and oocyst outputs as compared to non-vaccinated controls. The results suggest that the rEtCHP18905 protein can induce partial immune protection against infection with E. tenella and could be an effective candidate for the development of new vaccines.

Identification and Protective Efficacy of Eimeria tenella Rhoptry Kinase Family Protein 17

“…One-week-old chickens were weighed and randomly placed into 4 groups, each consisting of 12 birds [ 9 ]. The experimental design of immunizations and challenges is shown in Table 1 .…”

“…rEtROP17 was expressed in Escherichia coli BL21 (DE3) and purified using the His60 Ni Gravity Columns (Takara, Dalian, China). Hence, the development of novel control measures such as subunit vaccines has attracted widespread attention [9]. Eimeria tenella is an important species owing to its association with many coccidiosis outbreaks [10].…”

“…However, the use of live anticoccidial vaccines or anti-parasitic drugs has disadvantages, such as the occurrence of drug resistance, complex production processes, and potential pathogenicity [7,8]. Hence, the Animals 2022, 12, 556 2 of 9 development of novel control measures such as subunit vaccines has attracted widespread attention [9].…”

“…In recent years, a number of E. tenella antigens have been tested as candidate antigens for subunit or DNA vaccines, such as surface antigen 16 (SAG16), SAG22, gametocyte 22 antigen, and silent information regulator 2 [ 9 , 14 , 15 ]. Currently, the protective efficacy of several proteins has been not evaluated, such as EtROP17.…”

Evaluation of the immune protective effects of rEmMIC2 and rEmMIC3 from Eimeria magna in rabbits

“…They are secreted by microneme organelles that promote adhesion between parasites and the surface of host cells and perform the dynamics required for host cell invasion (Carruthers and Tomley 2008 ). Microneme proteins were found to effectively protect hosts from parasites in Toxoplasma gondii and chicken coccidia (Lee et al 2018 ; Sathish et al 2011 ; Zhao et al 2021a , b ); however, no studies have been reported on rabbit coccidia.…”