Identification and Evaluation of Novel Antigen Candidates against Salmonella Pullorum Infection Using Reverse Vaccinology

Abstract

Pullorum disease, caused by the Salmonella enterica serovar Gallinarum biovar Pullorum, is a highly contagious disease in the poultry industry, leading to significant economic losses in many developing countries. Due to the emergence of multidrug-resistant (MDR) strains, immediate attention is required to prevent their endemics and global spreading. To mitigate the prevalence of MDR S. Pullorum infections in poultry farms, it is urgent to develop effective vaccines. Reverse vaccinology (RV) is a promising approach using expressed genomic sequences to find new vaccine targets. The present study used the RV approach to identify new antigen candidates against Pullorum disease. Initial epidemiological investigation and virulent assays were conducted to select strain R51 for presentative and general importance. An additional complete genome sequence (4.7 Mb) for R51 was resolved using the Pacbio RS II platform. The proteome of S. Pullorum was analyzed to predict outer membrane and extracellular proteins, and was further selected for evaluating transmembrane domains, protein prevalence, antigenicity, and solubility. Twenty-two high-scored proteins were identified among 4713 proteins, with 18 recombinant proteins successfully expressed and purified. The chick embryo model was used to assess protection efficacy, in which vaccine candidates were injected into 18-day-old chick embryos for in vivo immunogenicity and protective effects. The results showed that the PstS, SinH, LpfB, and SthB vaccine candidates were able to elicit a significant immune response. Particularly, PstS confers a significant protective effect, with a 75% survival rate compared to 31.25% for the PBS control group, confirming that identified antigens can be promising targets against S. Pullorum infection. Thus, we offer RV to discover novel effective antigens in an important veterinary infectious agent with high priority.

Conserved Domains in Variable Surface Lipoproteins A-G of Mycoplasma hyorhinis May Serve as Probable Multi-Epitope Candidate Vaccine: Computational Reverse Vaccinology Approach

“…A study conducted by Li and colleagues used the computational approach to propose the vaccine candidate and successfully evaluated its efficacy in mice models [ 37 ]. Implementing a computational reverse vaccinology approach and its success in in vivo experiments are supported by several studies [ 39 , 40 , 41 , 42 ].…”

Mobilome-driven partitions of the resistome in Salmonella

“…Additional information about Salmonella strains was also collected, including the collection time, serovar distribution, and source of isolation. A laboratory-derived Salmonella (R51) was also included in this analysis ( 33 , 34 ), which was conducted by the Pacbio RSII sequencing (Beijing Novogene Co. Ltd).…”

Identification of the gut microbiota affecting Salmonella pullorum and their relationship with reproductive performance in hens

“…Previous studies suggested that in mainland China, PD was highly prevalent in the autumn, followed by the winter. Their findings also demonstrated that PD still posed a major threat to the poultry industry and that comprehensive and stringent strategies should be used to prevent and control this disease (Lv et al, 2022 ; Jiang et al, 2023 ). There is conclusive evidence that increased stocking density and larger farms result in an increased occurrence, persistence, and spread of Salmonella in laying hen flocks (Hazards et al, 2019 ).…”