Evaluation of immunoprotective effects of recombinant protein and DNA vaccine based on Eimeria tenella surface antigen 16 and 22 in vivo

Abstract

Coccidiosis triggered by Eimeria tenella is accompanied by haemorrhagic caecum and high morbidity. Vaccines are preferable choices to replace chemical drugs against coccidiosis. Surface antigens of apicomplexan parasites can adhere to host cells during the infection process. Therefore, truncated fragments coding E. tenella surface antigen 16 (EtSAG16) and 22 (EtSAG22) were cloned into pET-28a prokaryotic vector to express recombinant protein 16 (rEtSAG16) and 22 (rEtSAG22), respectively. Likewise, pEGFP-N1-EtSAG16 and pEGFP-N1-EtSAG22 plasmids were constructed using pEGFP-N1 eukaryotic vector. Further, pEGFP-N1-EtSAG4-16-22 multiple gene plasmid carrying EtSAG4, 16 and 22 were designed as cocktail vaccines to study integral immunoprotective effects. Western blot and RT-PCR (reverse transcription) assay were performed to verify expressions of EtSAG16 and 22 genes. Immunoprotective effects of recombinant protein or DNA vaccine were evaluated using different doses (50 or 100 μg) in vivo. All chickens in the vaccination group showed higher cytokine concentration (IFN-γ and IL-17), raised IgY antibody level, increased weight gain, lower caecum lesion score and reduced oocyst shedding compared with infection control groups ( p < 0.05). The highest anticoccidial index (ACI) value 173.11 was from the pEGFP-N1-EtSAG4-16-22 plasmid (50 μg) group. In conclusion, EtSAG16 and 22 might be alternative candidate genes for generating vaccines against E. tenella infection.

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

“…This was further confirmed by the subsequent assay in the present study, which showed that chickens immunized with rEtROP17 had a significant increase in IgY titers compared with those of the challenged control and the unchallenged control groups. No significant differences between the challenged and the unchallenged groups in IgY titer were observed, which was consistent with the results of a previous study [ 29 ].…”

Construction of recombinant SAG22 Bacillus subtilis and its effect on immune protection of coccidia

“…The expression of SAG is differentially regulated between oocyst/zygotes and second-generation cleavage stages, with only one being specifically expressed in the zygotes, a few in both stages, and most in the second generation cleavage ( Tabares et al, 2004 ), with the SAG B gene being specifically expressed in the second-generation cleavage peak expression in the second generation of cleistogamy. In recent years, many researchers have investigated the immunogenicity of SAG proteins, such as SAG1 ( Vo et al, 2021 ), SAG2, SAG4 ( Zhao et al, 2020b ), SAG6, SAG15 ( Geng et al, 2022 ), SAG16, SAG22, SAG23 ( Song et al, 2021 ; Zhao et al, 2021 ), among which SAG1, SAG4, SAG15, and SAG22 have candidate antigenic genes to be anticoccidial vaccines. In general, protective antigens will prefer proteins expressed in the intracellular phase or in the metabolically active phase of the worm, whereas SAG22 belongs to the SAG B gene, which is capable of efficient expression in the second generation of cleavers.…”

“…In general, protective antigens will prefer proteins expressed in the intracellular phase or in the metabolically active phase of the worm, whereas SAG22 belongs to the SAG B gene, which is capable of efficient expression in the second generation of cleavers. In a study ( Zhao et al, 2021 ), a truncated fragment encoding the surface antigen SAG22 of E. tenella was cloned into the pET-28 and expressed in the E. coli expression system, the recombinant protein SAG22 has immune protective effect on broilers. However, immune protection was only studied on d 14 chicks, and the immune protection was weak.…”

“…Therefore, screening for antigens with high expression in the lytic phase is a reasonable way to develop an anticoccidial vaccine ( Clark et al, 2016 ). SAG22 is one of SAG B gene with peak expression in both second-generation lytics, and it has been shown that SAG22 triggers moderate immune protection ( Zhao et al, 2021 ), so SAG22 could be an effective candidate vaccine antigen against Eimeria crassa .…”

Bacillus subtilis Expressing Chicken NK-2 Peptide Enhances the Efficacy of EF-1α Vaccination in Eimeria maxima-Challenged Broiler Chickens

“…However, the emergence of drug resistance to anticoccidial drugs and genetic variants of Eimeria strains, as well as the issue of residual virulence, have been consistently identified as potential risk factors [ 6 , 10 , 11 ]. Increasing scientific evidence indicates that recombinant anticoccidial vaccines are promising alternatives to antibiotics in the control of coccidiosis in poultry [ 12 ]. Over the last decades, recombinant protein technology has become efficient and relatively inexpensive through the use of microbial and other expression host systems [ 13 ].…”