Identification of Vaccine-Reactive Campylobacter jejuni Outer Membrane Proteins Recognized by Antibodies from Immunized Layer Breeders and Their Offspring

Background/Objectives: Our recent study demonstrated that vaccination of layer breeders with Campylobacter jejuni outer membrane proteins (OMPs) and CpG ODN increased serum IgY levels and enhanced maternal antibody transfer to their offspring. However, it remained unclear which specific proteins within the OMP fraction were responsible for these effects. Methods: In this study, Western blotting (WB) and ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) were used to identify proteins associated with elevated antibody responses. Results: Among the identified proteins, seven were found in high abundance and showed strong reactivity with both hen and offspring sera. These proteins included major outer membrane protein (MOMP), fibronectin type III domain protein (FlpA), type IV secretion system protein (VirB10), capsular polysaccharide ABC transporter (KpsD), flagellin (FlaA), flagellar hook protein (FlgE), and flagellar hook-associated protein (FliD). Conclusion: Several immunoreactive candidate proteins were identified in this study; however, further validation via recombinant expression is required to evaluate their potential as vaccine candidates against C. jejuni in chickens.