Figure 1.Vector construct for expression of ORF1 and ORF2 using pTrc99A.(Munar M P,et al.2019)
Figure 2.Spot-plating was used to observe the tellurite-reducing activity of a E.coli strain A1 and b the ORF-expression clones on LB agar plates with 20μg/mL chloramphenicol(CHL)or 100μg/mL ampicillin(AMP)containing 1 mM Na2TeO3.WT:wild-type E.coli cells,WT/P1:wild-type E.coli carrying empty vector pHSG398,WT/P2:wild-type E.coli carrying empty vector pTrc99A,A1:E.coli strain A1;A1-ORF1 and A1-ORF2:recombinant E.coli clones containing pTrc99AORF1 and pTrc99A-ORF2 respectively.(Munar M P,et al.2019)
Comparison of C. hepaticus loads in liver and cecal samples across the experimental groups by quantitative real-time PCR.
Identification and Expression of Immunogenic Mimotopes of C. hepaticus Using an E. coli-Based Surface Display System
Paper
2026
Vaccines |
DOI
Background
This study addresses spotty liver disease (SLD) in layer hens caused by Campylobacter hepaticus by identifying and expressing immunogenic mimotopes on the surface of an attenuated avian pathogenic Escherichia coli (APEC) vector. Phage display selection using hyperimmune sera revealed 14 mimotopes, which were inserted into an OmpC scaffold for surface expression. Chicken vaccination-challenge trials showed that mimotopes derived from flagellar proteins (FliK, FlaA) and MOMP induced significant IgG and IgA responses, conferred complete protection against C. hepaticus colonization in liver and bile, and reduced hepatic bacterial loads. This work provides a promising live-attenuated vaccine platform for SLD control.
Key Findings
Fourteen immunogenic mimotopes corresponding to 13 C. hepaticus proteins were identified using phage display. An OmpC-based surface display system successfully expressed 12-amino-acid mimotopes with a 6xHis tag on E. coli DH5α ΔompC and on the live-attenuated APEC PSUO78 ΔaroA Δasd vaccine vector, confirmed by Western blot at 48 kDa. Among the mimotopes tested, two flagellar-related mimotopes (mimotope-2 from FliK and mimotope-4 from FlaA) and one MOMP-derived mimotope (mimotope-5) elicited significant serum IgG and intestinal IgA responses in vaccinated chickens. These three mimotope vaccines provided 100% protection against C. hepaticus challenge, with no bacterial recovery from liver and bile in vaccinated groups, whereas all unvaccinated challenged controls were positive. Quantitative PCR showed a significant reduction (up to 9.83-fold) in hepatic C. hepaticus loads in vaccinated groups compared to controls, although cecal colonization was not markedly affected. This platform enables multivalent mimotope vaccine development against SLD and potentially APEC.
Contribution
Creative Biogene provided the lyophilized pTrc99a expression vector used for OmpC-mimotope surface display construction, as cited in the methods.
This study addresses spotty liver disease (SLD) in layer hens caused by Campylobacter hepaticus by identifying and expressing immunogenic mimotopes on the surface of an attenuated avian pathogenic Escherichia coli (APEC) vector. Phage display selection using hyperimmune sera revealed 14 mimotopes, which were inserted into an OmpC scaffold for surface expression. Chicken vaccination-challenge trials showed that mimotopes derived from flagellar proteins (FliK, FlaA) and MOMP induced significant IgG and IgA responses, conferred complete protection against C. hepaticus colonization in liver and bile, and reduced hepatic bacterial loads. This work provides a promising live-attenuated vaccine platform for SLD control.
Key Findings
Fourteen immunogenic mimotopes corresponding to 13 C. hepaticus proteins were identified using phage display. An OmpC-based surface display system successfully expressed 12-amino-acid mimotopes with a 6xHis tag on E. coli DH5α ΔompC and on the live-attenuated APEC PSUO78 ΔaroA Δasd vaccine vector, confirmed by Western blot at 48 kDa. Among the mimotopes tested, two flagellar-related mimotopes (mimotope-2 from FliK and mimotope-4 from FlaA) and one MOMP-derived mimotope (mimotope-5) elicited significant serum IgG and intestinal IgA responses in vaccinated chickens. These three mimotope vaccines provided 100% protection against C. hepaticus challenge, with no bacterial recovery from liver and bile in vaccinated groups, whereas all unvaccinated challenged controls were positive. Quantitative PCR showed a significant reduction (up to 9.83-fold) in hepatic C. hepaticus loads in vaccinated groups compared to controls, although cecal colonization was not markedly affected. This platform enables multivalent mimotope vaccine development against SLD and potentially APEC.
Contribution
Creative Biogene provided the lyophilized pTrc99a expression vector used for OmpC-mimotope surface display construction, as cited in the methods.