Selection of specific peptides recognised by polyclonal antibody from Salmonella enteritidis infected chicken using next generation phage display technology

Salmonella Enteritidis is an important cause of human salmonellosis and food-poisoning associated with consumption of contaminated chicken eggs and poultry products. Objective of the study was to develop a serological diagnostic testfor the recognition of different Salmonella serovars in chickens. Here, phage peptide libraries were screened against 9 IgY samples from chickens infected with S. Enteritidis and 9 IgY samples with S. Hadar and the individual peptide binders were then identified using NGS. Twenty-nine peptides were identifiedin silico assessmentas being enriched specifically against IgY from multiple chickens infected with S. Enteritidis compared to those infected with S. Hadar. Twenty Nine peptides identifiedin silico assessmentwere thentested by both training and test cohorts of chicken IgY samples in ELISAs. The training set of samples was made upof IgY from 9 chickens infected with S. Enteritidis and 9 infected with S. Hadar. Seventeen peptides were selected as the most recognized specific peptides against S. Enteritidis infection and were then used against IgY samples from10 birds infected with S. Enteritids and20 birds with S. Typhimurium as a test cohort. Overall, for both training and test cohorts the peptide ELISA assay sensitivity and specificity were 90 % for detecting infections. The most discriminatory peptides by ELISA test were AEGEFEPQSARPS and AEGEFFVNRALINQ. The data demonstrated that the NGPD method could identify peptides that represented serovar-specific epitopes/mimotopes, these peptide have potentially important applications for the development of peptide based immuno-diagnostic assays for the recognition of Salmonella Enteritidis in chickens.