Mapping B-cell responses to Salmonella enterica serovars Typhimurium and Enteritidis in chickens for the discrimination of infected from vaccinated animals

Abstract

Serological surveillance and vaccination are important strategies for controlling infectious diseases of food production animals. However, the compatibility of these strategies is limited by a lack of assays capable of differentiating infected from vaccinated animals (DIVA tests) for established killed or attenuated vaccines. Here, we used next generation phage-display (NGPD) and a 2-proportion Z score analysis to identify peptides that were preferentially bound by IgY from chickens infected with Salmonella Typhimurium or S. Enteritidis compared to IgY from vaccinates, for both an attenuated and an inactivated commercial vaccine. Peptides that were highly enriched against IgY from at least 4 out of 10 infected chickens were selected: 18 and 12 peptides for the killed and attenuated vaccines, respectively. The ten most discriminatory peptides for each vaccine were identified in an ELISA using a training set of IgY samples. These peptides were then used in multi-peptide assays that, when analysing a wider set of samples from infected and vaccinated animals, diagnosed infection with 100% sensitivity and specificity. The data describes a method for the development of DIVA assays for conventional attenuated and killed vaccines.

Discovery of peptide ligands targeting a specific ubiquitin-like domain–binding site in the deubiquitinase USP11

“…After three biopanning rounds, phage ssDNA was extracted and purified, and peptide sequences were amplified and deep-sequenced. To rank the identified sequences, a two-proportion Z test–based method (31, 32) was applied to round 3 output phage, and analysis of the 50 sequences with the highest Z scores after three rounds of panning (Fig. S1) revealed the presence of two sequence motifs: (YNHC)-(±)-L-(±)-φ-R (motif 1, based on 18 peptides) and a L- X -L-φ- X-X -S-(RP) (motif 2, based on 29 peptides), where X stands for any residue, (±) for charged residues, and φ for nonpolar residues.…”

“…Subsequently, phage ssDNA was precipitated with ethanol and stored as a dry pellet to be used as a PCR template. For the amplification of the unknown peptide sequences, a two-step PCR strategy was followed, as described previously (32). The strategy produced an amplicon of ∼330 bp, and each sample contained a unique barcoded sequence.…”

IgYs: on her majesty’s secret service

“…The determination of the IgY antibodies level and their specificity is also used for monitoring serological response of infected chickens ( 269 ), differentiation between infected and vaccinated animals (DIVA strategy) ( 270 ), and description potential of cross-protective immunity against challenge with S. typhimurium and S. enteritidis ( 271 ). Senevirathne et al.…”

Obtaining, purification and characterization of specific immunoglobulin Y with diagnostic and prophylactic aims

“…Empleando la técnica de ELISA se están logrando cada vez más aplicaciones, como el diagnós-tico de la Diarrea Viral Bovina (Zhang et al 2016). Un ensayo realizado por Naqid et al (2016) permitió diferenciar entre los anticuerpos producidos en aves infectadas por Salmonella typhimurium y Salmonella enteritidis de aquellos producidos en aves vacunadas. Esto abre un interesante campo de aplicación en las estrategias que deben aplicarse en la vigilancia serológica y la vacunación para el control de enfermedades infecciosas de los animales de producción de alimentos.…”