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Updated: Dec 24, 2025
Ex Vivo Infection of Murine Epidermis with Herpes Simplex Virus Type 1
Published on: August 24, 2015
Identification of Haemophilus parasuis genes uniquely expressed during infection using in vivo-induced antigen
Weiting Mao1, Shu Zhang1, Ju Sun1
1State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, China; Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, 430070, China.
Abstract:
Haemophilus parasuis is the etiological agent of Glässer's disease which is characterized by fibrinous polyserositis, arthritis and meningitis. The pathogenesis of this bacterium remains largely unknown. Genes expressed in vivo may play an important role in the pathogenicity of H. parasuis. The development of in vivo-induced antigen technology (IVIAT) has provided a valuable tool for the identification of in vivo-induced genes during bacterial infection. In this study, IVIAT was applied to identify in vivo-induced antigens of H. parasuis. Pooled swine H. parasuis-positive sera, adsorbed against in vitro-grown cultures of H. parasuis SH0165 and Escherichia coli BL21 (DE3), were used to screen the inducible expression library of genomic proteins from whole genome sequenced H. parsuis SH0165. Finally, 24 unique genes expressed in vivo were successfully identified after secondary and tertiary screening with IVIAT. These genes were implicated in cell surface proteins, metabolism, stress response, regulation, transportation and other processes. Quantitative real-time PCR showed that the mRNA levels of 24 genes were all upregulated in vivo relative to in vitro, with 13 genes were detected significantly upregulated in H. parasuis infected pigs. Several potential virulence-associated genes were found to be uniquely expressed in vivo, including espP, lnt, hutZ, mreC, vtaA, pilB, tex, sunT and aidA. The results indicated that the proteins identified using IVIAT may play important roles in the pathogenesis of H. parasuis infection in vivo.
Insights
Haemophilus parasuis causes Glässer's disease. Researchers used in vivo-induced antigen technology (IVIAT) to identify 24 genes expressed during infection, revealing potential virulence factors crucial for H. parasuis pathogenesis.
Area of Science:
- Veterinary Microbiology
- Bacterial Pathogenesis
- Molecular Biology
Background:
- Haemophilus parasuis is the primary cause of Glässer's disease in swine, a condition marked by polyserositis, arthritis, and meningitis.
- The precise mechanisms underlying H. parasuis pathogenesis remain poorly understood, highlighting the need to investigate bacterial adaptation during infection.
- Genes expressed by bacteria within the host environment (in vivo) are critical for understanding virulence and developing effective control strategies.
Purpose of the Study:
- To identify genes and antigens of H. parasuis that are specifically expressed during infection in vivo.
- To utilize the in vivo-induced antigen technology (IVIAT) as a tool for discovering novel virulence-associated factors of H. parasuis.
- To characterize the functional roles of identified in vivo-expressed genes in the context of H. parasuis pathogenicity.
Main Methods:
- Application of in vivo-induced antigen technology (IVIAT) using pooled swine sera from H. parasuis-infected pigs.
- Screening of a genomic expression library of H. parasuis SH0165 against adsorbed swine sera to identify in vivo-induced antigens.
- Validation of identified gene expression levels using quantitative real-time PCR (qRT-PCR) in infected pigs versus in vitro cultures.
Main Results:
- Successfully identified 24 unique genes expressed in vivo by H. parasuis, involved in various cellular processes including metabolism, stress response, and transport.
- Quantitative real-time PCR confirmed upregulation of all 24 identified genes in vivo, with 13 showing significant upregulation in infected pigs.
- Several potential virulence-associated genes, such as espP, lnt, hutZ, mreC, vtaA, pilB, tex, sunT, and aidA, were found to be uniquely expressed in vivo.
Conclusions:
- The proteins encoded by the identified 24 genes are likely crucial for H. parasuis survival and virulence within the host.
- IVIAT is an effective method for discovering novel virulence factors of H. parasuis expressed during active infection.
- Further investigation into these in vivo-expressed proteins will enhance our understanding of Glässer's disease pathogenesis and inform the development of targeted interventions.
