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Huang J, Kang W, Yi D, Zhu S, Xiang Y, Liu C, Li H, Dai D, Su J, He J, Liang Z. Intranasal B5 promotes mucosal defence against Actinobacillus pleuropneumoniae via ameliorating early immunosuppression. Virulence 2024; 15:2316459. [PMID: 38378464 PMCID: PMC10880497 DOI: 10.1080/21505594.2024.2316459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 02/04/2024] [Indexed: 02/22/2024] Open
Abstract
Actinobacillus pleuropneumoniae (APP) is an important pathogen of the porcine respiratory disease complex, which leads to huge economic losses worldwide. We previously demonstrated that Pichia pastoris-producing bovine neutrophil β-defensin-5 (B5) could resist the infection by the bovine intracellular pathogen Mycobacterium bovis. In this study, the roles of synthetic B5 in regulating mucosal innate immune response and protecting against extracellular APP infection were further investigated using a mouse model. Results showed that B5 promoted the production of tumour necrosis factor (TNF)-α, interleukin (IL)-1β, and interferon (IFN)-β in macrophages as well as dendritic cells (DC) and enhanced DC maturation in vitro. Importantly, intranasal B5 was safe and conferred effective protection against APP via reducing the bacterial load in lungs and alleviating pulmonary inflammatory damage. Furthermore, in the early stage of APP infection, we found that intranasal B5 up-regulated the secretion of TNF-α, IL-1β, IL-17, and IL-22; enhanced the rapid recruitment of macrophages, neutrophils, and DC; and facilitated the generation of group 3 innate lymphoid cells in lungs. In addition, B5 activated signalling pathways associated with cellular response to IFN-β and activation of innate immune response in APP-challenged lungs. Collectively, B5 via the intranasal route can effectively ameliorate the immune suppression caused by early APP infection and provide protection against APP. The immunization strategy may be applied to animals or human respiratory bacterial infectious diseases. Our findings highlight the potential importance of B5, enhancing mucosal defence against intracellular bacteria like APP which causes early-phase immune suppression.
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Affiliation(s)
- Jingsheng Huang
- College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Weichao Kang
- College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Dandan Yi
- College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Shuxin Zhu
- College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Yifei Xiang
- College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Chengzhi Liu
- College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Han Li
- College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Dejia Dai
- College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Jieyu Su
- College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Jiakang He
- College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Zhengmin Liang
- College of Animal Science and Technology, Guangxi University, Nanning, China
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Guo F, Quan R, Cui Y, Cao X, Wen T, Xu F. Effects of OxyR regulator on oxidative stress, Apx toxin secretion and virulence of Actinobacillus pleuropneumoniae. Front Cell Infect Microbiol 2024; 13:1324760. [PMID: 38268788 PMCID: PMC10806198 DOI: 10.3389/fcimb.2023.1324760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 12/18/2023] [Indexed: 01/26/2024] Open
Abstract
Introduction Actinobacillus pleuropneumoniae, the causative agent of porcine pleuropneumonia, poses a significant threat to global swine populations due to its high prevalence, mortality rates, and substantial economic ramifications. Understanding the pathogen's defense mechanisms against host-produced reactive oxygen species is crucial for its survival, with OxyR, a conserved bacterial transcription factor, being pivotal in oxidative stress response. Methods This study investigated the presence and role of OxyR in A. pleuropneumoniae serovar 1-12 reference strains. Transcriptomic analysis was conducted on an oxyR disruption mutant to delineate the biological activities influenced by OxyR. Additionally, specific assays were employed to assess urease activity, catalase expression, ApxI toxin secretion, as well as adhesion and invasion abilities of the oxyR disruption mutant on porcine 3D4/21 and PT cells. A mice challenge experiment was also conducted to evaluate the impact of oxyR inactivation on A. pleuropneumoniae virulence. Results OxyR was identified as a conserved regulator present in A. pleuropneumoniae serovar 1-12 reference strains. Transcriptomic analysis revealed the involvement of OxyR in multiple biological activities. The oxyR disruption resulted in decreased urease activity, elevated catalase expression, enhanced ApxI toxin secretion-attributed to OxyR binding to the apxIBD promoter-and reduced adhesion and invasion abilities on porcine cells. Furthermore, inactivation of oxyR reduced the virulence of A. pleuropneumoniae in a mice challenge experiment. Discussion The findings highlight the pivotal role of OxyR in influencing the virulence mechanisms of A. pleuropneumoniae. The observed effects on various biological activities underscore OxyR as an essential factor contributing to the pathogenicity of this bacterium.
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Affiliation(s)
- Fangfang Guo
- Beijing Key Laboratory for Prevention and Control of Infectious Diseases in Livestock and Poultry, Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
| | - Rong Quan
- Beijing Key Laboratory for Prevention and Control of Infectious Diseases in Livestock and Poultry, Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
| | - Yifang Cui
- Beijing Key Laboratory for Prevention and Control of Infectious Diseases in Livestock and Poultry, Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
| | - Xiaoya Cao
- Beijing Key Laboratory for Prevention and Control of Infectious Diseases in Livestock and Poultry, Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
| | - Tong Wen
- Department of Biology Science and Technology, Baotou Teacher’s College, Baotou, China
| | - Fuzhou Xu
- Beijing Key Laboratory for Prevention and Control of Infectious Diseases in Livestock and Poultry, Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
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Zhang L, Zhao F, Xu H, Chen Y, Qi C, Liu J. HtrA of Actinobacillus pleuropneumoniae is a virulence factor that confers resistance to heat shock and oxidative stress. Gene 2022; 841:146771. [PMID: 35905850 DOI: 10.1016/j.gene.2022.146771] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Revised: 07/01/2022] [Accepted: 07/24/2022] [Indexed: 11/04/2022]
Abstract
Actinobacillus pleuropneumoniae is the causative agent of porcine pleuropneumonia, which is a severe and often fatal disease that results in significant economic loss. The means by which A. pleuropneumoniae survives within the host are not clear. High temperature requirement A (HtrA) proteases have been shown to affect cell viability during stressful conditions and are virulence factors in many bacterial species. In this study, we examined the biological role of HtrA during A. pleuropneumoniae infection by analyzing the impact of htrA mutation on virulence-associated phenotypes. We found that htrA mutation had a dramatic impact on stress tolerance. The htrA mutant (ΔhtrA) displayed a lethal phenotype at elevated temperature (42°C). Further, ΔhtrA exhibited increased susceptibility to H2O2-induced oxidative stress when compared to the parental strain (SLW01) and a complementation strain (ΔhtrA-Compl). Animal infection assays demonstrated that absence of HtrA led to decreased in vivo colonization ability, and ΔhtrA is less virulent in pigs relative to SLW01. Furthermore, pig competitive infection assays demonstrated fewer blood associated CFUs with ΔhtrA infection than with SLW01. These results demonstrate HtrA plays a significant role in the survival and growth of A. pleuropneumoniae during stressful conditions, and that immune escape and invasiveness are important to the process of A. pleuropneumoniae infection.
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Affiliation(s)
- Li Zhang
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, Hubei 430079, China
| | - Fan Zhao
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, Hubei 430079, China
| | - Huan Xu
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, Hubei 430079, China
| | - Yubing Chen
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, Hubei 430079, China
| | - Chao Qi
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, Hubei 430079, China.
| | - Jinlin Liu
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, Hubei 430079, China.
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Nahar N, Turni C, Tram G, Blackall PJ, Atack JM. Actinobacillus pleuropneumoniae: The molecular determinants of virulence and pathogenesis. Adv Microb Physiol 2021; 78:179-216. [PMID: 34147185 DOI: 10.1016/bs.ampbs.2020.12.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Actinobacillus pleuropneumoniae, the causative agent of porcine pleuropneumonia, is responsible for high economic losses in swine herds across the globe. Pleuropneumonia is characterized by severe respiratory distress and high mortality. The knowledge about the interaction between bacterium and host within the porcine respiratory tract has improved significantly in recent years. A. pleuropneumoniae expresses multiple virulence factors, which are required for colonization, immune clearance, and tissue damage. Although vaccines are used to protect swine herds against A. pleuropneumoniae infection, they do not offer complete coverage, and often only protect against the serovar, or serovars, used to prepare the vaccine. This review will summarize the role of individual A. pleuropneumoniae virulence factors that are required during key stages of pathogenesis and disease progression, and highlight progress made toward developing effective and broadly protective vaccines against an organism of great importance to global agriculture and food production.
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Affiliation(s)
- Nusrat Nahar
- Institute for Glycomics, Griffith University, Gold Coast, QLD, Australia
| | - Conny Turni
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, QLD, Australia
| | - Greg Tram
- Institute for Glycomics, Griffith University, Gold Coast, QLD, Australia
| | - Patrick J Blackall
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, QLD, Australia.
| | - John M Atack
- Institute for Glycomics, Griffith University, Gold Coast, QLD, Australia.
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Antenucci F, Magnowska Z, Nimtz M, Roesch C, Jänsch L, Bojesen AM. Immunoproteomic characterization of outer membrane vesicles from hyper-vesiculating Actinobacillus pleuropneumoniae. Vet Microbiol 2019; 235:188-194. [PMID: 31383301 DOI: 10.1016/j.vetmic.2019.07.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 07/02/2019] [Accepted: 07/02/2019] [Indexed: 11/16/2022]
Abstract
Outer membrane vesicles (OMVs) are produced and secreted virtually by every known Gram-negative bacterium. Despite their non-live nature, they share antigenic characteristics with the bacteria they originate from. This, together with their relative ease of purification, casts the OMVs as a very promising and flexible tool in both human and veterinary vaccinology. The aim of the current work was to get an insight into the antigenic pattern of OMVs from the pig pathogen Actinobacillus pleuropneumoniae in the context of vaccine development. Accordingly, we designed a protocol combining 2D Western Blotting and mass spectrometric identification to robustly characterize the antigenic protein pattern of the vesicles. Our analysis revealed that A. pleuropneumoniae OMVs carry several immunoreactive virulence factors. Some of these proteins, LpoA, OsmY and MIDG2331_02184, have never previously been documented as antigenic in A. pleuropneumoniae or other pathogenic bacteria. Additionally, we showed that despite their relative abundance, proteins such as FrpB and DegQ do not contribute to the antigenic profile of A. pleuropneumoniae OMVs.
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Affiliation(s)
- Fabio Antenucci
- Department of Veterinary and Animal Sciences, Stigbøjlen 4, 1870 Frb. C., 1-20, Building: 301, University of Copenhagen, Copenhagen, Denmark.
| | - Zofia Magnowska
- Department of Veterinary and Animal Sciences, Stigbøjlen 4, 1870 Frb. C., 1-20, Building: 301, University of Copenhagen, Copenhagen, Denmark.
| | - Manfred Nimtz
- Helmholtz Centre for Infection Research, Inhoffenstraße 7, 38124, Braunschweig, Germany.
| | - Camille Roesch
- Izon Science Ltd, Batiment Laennec, 60 Avenue Rockefeller, 69008, Lyon, France.
| | - Lothar Jänsch
- Helmholtz Centre for Infection Research, Inhoffenstraße 7, 38124, Braunschweig, Germany.
| | - Anders Miki Bojesen
- Department of Veterinary and Animal Sciences, Stigbøjlen 4, 1870 Frb. C., 1-20, Building: 301, University of Copenhagen, Copenhagen, Denmark.
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Qu S, Dai C, Yang F, Huang T, Hao Z, Tang Q, Wang H, Zhang Y. Cefquinome-Loaded Microsphere Formulations in Protection against Pneumonia with Klebsiella pneumonia Infection and Inflammatory Response in Rats. Pharm Res 2019; 36:74. [PMID: 30923922 DOI: 10.1007/s11095-019-2614-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Accepted: 03/22/2019] [Indexed: 01/02/2023]
Abstract
PURPOSE This study aimed to compare in vivo activity between cefquinome (CEQ)-loaded poly lactic-co-glycolic acid (PLGA) microspheres (CEQ-PLGA-MS) and CEQ injection (CEQ-INJ) against Klebsiella pneumonia in a rat lung infection model. METHODS Forty-eight rats were divided into control group (sham operated without infection and drug treatment), Klebsiella pneumonia model group (KPD + Saline), CEQ-PLGA-MS and CEQ-INJ therapy groups (KPD + CEQ-PLGA-MS and KPD + INJ, respectively). In the KPD + Saline group, rats were infected with Klebsiella pneumonia ATCC 10031. In the KPD + CEQ-PLGA-MS and KPD + INJ groups, infected rats were intravenously injected with 12.5 mg/kg body weight CEQ-PLGA-MS and CEQ-INJ, respectively. RESULTS Compared to CEQ-INJ treatment group, CEQ-PLGA-MS treatment further decreased the number of bacteria colonies (decreased to 1.94 lg CFU/g) in lung tissues and the levels of inflammatory cytokine including tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, IL-4 (p < 0.05 or p < 0.01) in bronchoalveolar lavage fluid at 48 h. Consistently, a significant decreases of scores of inflammation severity were showed at 48 h in the KPD + CEQ-PLGA-MS treatment group, compared to the KPD + CEQ-INJ treatment group. CONCLUSION Our results reveal that CEQ-PLGA-MS has the better therapeutic effect than CEQ-INJ for Klebsiella pneumonia lung infections in rats. The vehicle of CEQ-PLGA-MS as the promising alternatives to control the lung infections with the important pathogens.
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Affiliation(s)
- Shaoqi Qu
- College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University, Qingdao, 266109, China.,National-Local Joint Engineering Laboratory of Agricultural Bio-pharmaceutical Technology, Qingdao, 266109, China
| | - Cunchun Dai
- College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University, Qingdao, 266109, China.,National-Local Joint Engineering Laboratory of Agricultural Bio-pharmaceutical Technology, Qingdao, 266109, China
| | - Fenfang Yang
- College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University, Qingdao, 266109, China.,National-Local Joint Engineering Laboratory of Agricultural Bio-pharmaceutical Technology, Qingdao, 266109, China
| | - Tingting Huang
- College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University, Qingdao, 266109, China.,National-Local Joint Engineering Laboratory of Agricultural Bio-pharmaceutical Technology, Qingdao, 266109, China
| | - Zhihui Hao
- College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University, Qingdao, 266109, China. .,National-Local Joint Engineering Laboratory of Agricultural Bio-pharmaceutical Technology, Qingdao, 266109, China.
| | - Qihe Tang
- College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University, Qingdao, 266109, China.,National-Local Joint Engineering Laboratory of Agricultural Bio-pharmaceutical Technology, Qingdao, 266109, China
| | - Haixia Wang
- College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University, Qingdao, 266109, China.,National-Local Joint Engineering Laboratory of Agricultural Bio-pharmaceutical Technology, Qingdao, 266109, China
| | - Yanping Zhang
- College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University, Qingdao, 266109, China.,National-Local Joint Engineering Laboratory of Agricultural Bio-pharmaceutical Technology, Qingdao, 266109, China
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7
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Qu S, Dai C, Zhu J, Zhao L, Li Y, Hao Z. Cefquinome-loaded microsphere formulations against Klebsiella pneumonia infection during experimental infections. Drug Deliv 2018; 25:909-915. [PMID: 29649952 PMCID: PMC6058672 DOI: 10.1080/10717544.2018.1461958] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 04/02/2018] [Accepted: 04/03/2018] [Indexed: 01/07/2023] Open
Abstract
The aim of this study was to prepare cefquinome-loaded polylactic acid microspheres and to evaluate their in vitro and in vivo characteristics and pharmacodynamics for the therapy of pneumonia in a rat model. Microspheres were prepared using a 0.7 mm two-fluid nozzle spray drier in one step resulting in spherical and smooth microspheres of uniform size (9.8 ± 3.6 μm). The encapsulation efficiency and drug loading of cefquinome were 91.6 ± 2.6% and 18.7 ± 1.2%, respectively. In vitro release of cefquinome from the microspheres was sustained for 36 h. Cefquinome-loaded polylactic acid microspheres as a drug delivery system was successful for clearing experimental Klebsiella pneumonia lung infections. A decrease in inflammatory cells and an inhibition of inflammatory cytokines TNF-α, IL-1β and IL-8 after microspheres treatment was found. Changes in cytokine levels and types are secondary manifestations of drug bactericidal effects. Rats were considered to be microbiologically cured because the bacterial load was less than 100 CFU/g. These results also indicated that the spray-drying method of loading therapeutic drug into polylactic acid microspheres is a straightforward and safe method for lung-targeting therapy in animals.
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Affiliation(s)
- Shaoqi Qu
- Agricultural Bio-pharmaceutical Laboratory, Qingdao Agricultural University, Qingdao, China
- National-Local Joint Engineering Laboratory, Agricultural Bio-pharmaceutical Technology, Qingdao, China
| | - Cunchun Dai
- Agricultural Bio-pharmaceutical Laboratory, Qingdao Agricultural University, Qingdao, China
- National-Local Joint Engineering Laboratory, Agricultural Bio-pharmaceutical Technology, Qingdao, China
| | - Jiajia Zhu
- Agricultural Bio-pharmaceutical Laboratory, Qingdao Agricultural University, Qingdao, China
- National-Local Joint Engineering Laboratory, Agricultural Bio-pharmaceutical Technology, Qingdao, China
| | - Li Zhao
- Agricultural Bio-pharmaceutical Laboratory, Qingdao Agricultural University, Qingdao, China
- National-Local Joint Engineering Laboratory, Agricultural Bio-pharmaceutical Technology, Qingdao, China
| | - Yuwen Li
- Agricultural Bio-pharmaceutical Laboratory, Qingdao Agricultural University, Qingdao, China
- National-Local Joint Engineering Laboratory, Agricultural Bio-pharmaceutical Technology, Qingdao, China
| | - Zhihui Hao
- Agricultural Bio-pharmaceutical Laboratory, Qingdao Agricultural University, Qingdao, China
- National-Local Joint Engineering Laboratory, Agricultural Bio-pharmaceutical Technology, Qingdao, China
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Yuan F, Liu J, You W, Bei W, Wang C, Zhao J, Tian Y, Liu S. Generation, safety and immunogenicity of an Actinobacillus pleuropneumoniae quintuple deletion mutant SLW07 (ΔapxICΔapxIICΔorf1ΔcpxARΔarcA). Vaccine 2018; 36:1830-1836. [PMID: 29486946 DOI: 10.1016/j.vaccine.2018.02.083] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 02/05/2018] [Accepted: 02/19/2018] [Indexed: 10/18/2022]
Abstract
We inactivated a virulence determinant, ArcA, in an Actinobacillus pleuropneumoniae quadruple deletion mutant SLW06 (ΔapxICΔapxIICΔorf1ΔcpxAR, serovar 1), and a quintuple deletion mutant SLW07 was generated. SLW07 showed decreased adherence to and invasion of host cells, compared to its parent strain SLW06. SLW07 was more sensitive in RAW264.7 macrophage-mediated phagocytosis and clearance. SLW07 was less virulent in mice. An immunization assay indicated that both SLW07 and SLW06 preferentially stimulated T helper cell type 2 response in mice. Live vaccines induced the production of interleukin-6 and tumor necrosis factor-α by splenic lymphocytes. Furthermore, the protective immunity of SLW07 was not affected after ArcA mutation. Immunization with SLW07 could provide a complete protection following virulent A. pleuropneumoniae challenge in mice. Our results suggest that SLW07 is a promising live vaccine candidate, which is further attenuated from and shares similar protective efficacy with its quadruple deletion parent SLW06.
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Affiliation(s)
- Fangyan Yuan
- Institute of Animal Husbandry and Veterinary Sciences, Hubei Academy of Agricultural Sciences, Key Laboratory of Prevention and Control Agents for Animal Bacteriosis (Ministry of Agriculture), Hubei Key Laboratory of Animal Embryo and Molecular Breeding, Wuhan, Hubei 430064, China
| | - Jinlin Liu
- College of Life Sciences, Central China Normal University, Wuhan, Hubei 430079, China
| | - Wujin You
- State Key Laboratory of Agricultural Microbiology, The Cooperative Innovation Center for Sustainable Pig Production, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Weicheng Bei
- State Key Laboratory of Agricultural Microbiology, The Cooperative Innovation Center for Sustainable Pig Production, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Chunlai Wang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China
| | - Jin Zhao
- College of Life Sciences, Central China Normal University, Wuhan, Hubei 430079, China
| | - Yiongxiang Tian
- Institute of Animal Husbandry and Veterinary Sciences, Hubei Academy of Agricultural Sciences, Key Laboratory of Prevention and Control Agents for Animal Bacteriosis (Ministry of Agriculture), Hubei Key Laboratory of Animal Embryo and Molecular Breeding, Wuhan, Hubei 430064, China.
| | - Siguo Liu
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China.
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To H, Nagai S, Iwata A, Koyama T, Oshima A, Tsutsumi N. Genetic and antigenic characteristics of ApxIIA and ApxIIIA from Actinobacillus pleuropneumoniae serovars 2, 3, 4, 6, 8 and 15. Microbiol Immunol 2017; 60:447-58. [PMID: 27211905 DOI: 10.1111/1348-0421.12388] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 04/21/2016] [Accepted: 05/16/2016] [Indexed: 11/30/2022]
Abstract
Apx toxins produced by Actinobacillus pleuropneumoniae are essential components of new generation vaccines. In this study, apxIIA and apxIIIA genes of serovars 2, 3, 4, 6, 8 and 15 were cloned and sequenced. Amino acid sequences of ApxIIA proteins of serovars 2, 3, 4, 6, 8 and 15 were almost identical to those of serovars 1, 5, 7, 9 and 11-13. Immunoblot analysis showed that rApxIIA from serovars 2 and 15 reacts strongly with sera from animals infected with various serovars. Sequence analysis revealed that ApxIIIA proteins has two variants, one in strains of serovar 2 and the other in strains of serovars 3, 4, 6, 8 and 15. A mouse cross-protection study showed that mice actively immunized with rApxIIIA/2 or rApxIIIA/15 are protected against challenge with A. pleuropneumoniae strains of serovars 3, 4, 6, 8, 15, and 2 expressing ApxIII/15 and ApxIII/2, respectively. Similarly, mice passively immunized with rabbit anti-rApxIIIA/2 or anti-rApxIIIA/15 sera were found to be protected against challenge with strains of serovars 2 and 15. Our study revealed antigenic and sequence similarities within ApxIIA and ApxIIIA proteins, which may help in the development of effective vaccines against disease caused by A. pleuropneumoniae.
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Affiliation(s)
- Ho To
- Nippon Institute for Biological Science, 9-2221-1 Shinmachi, Ome, Tokyo 198-0024, Japan
| | - Shinya Nagai
- Nippon Institute for Biological Science, 9-2221-1 Shinmachi, Ome, Tokyo 198-0024, Japan
| | - Akira Iwata
- Nippon Institute for Biological Science, 9-2221-1 Shinmachi, Ome, Tokyo 198-0024, Japan
| | - Tomohiro Koyama
- Nippon Institute for Biological Science, 9-2221-1 Shinmachi, Ome, Tokyo 198-0024, Japan
| | - Atsushi Oshima
- Nippon Institute for Biological Science, 9-2221-1 Shinmachi, Ome, Tokyo 198-0024, Japan
| | - Nobuyuki Tsutsumi
- Nippon Institute for Biological Science, 9-2221-1 Shinmachi, Ome, Tokyo 198-0024, Japan
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Liu J, Bai J, Lu Q, Zhang L, Jiang Z, Michal JJ, He Q, Jiang P. Two-dimensional liquid chromatography–tandem mass spectrometry coupled with isobaric tags for relative and absolute quantification (iTRAQ) labeling approach revealed first proteome profiles of pulmonary alveolar macrophages infected with porcine circovirus type 2. J Proteomics 2013; 79:72-86. [DOI: 10.1016/j.jprot.2012.11.024] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Revised: 11/14/2012] [Accepted: 11/28/2012] [Indexed: 01/02/2023]
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Seo KW, Kim SH, Park J, Son Y, Yoo HS, Lee KY, Jang YS. Nasal immunization with major epitope-containing ApxIIA toxin fragment induces protective immunity against challenge infection with Actinobacillus pleuropneumoniae in a murine model. Vet Immunol Immunopathol 2013. [DOI: 10.1016/j.vetimm.2012.10.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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12
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Shin MK, Kang ML, Jung MH, Cha SB, Lee WJ, Kim JM, Kim DH, Yoo HS. Induction of protective immune responses against challenge of Actinobacillus pleuropneumoniae by oral administration with Saccharomyces cerevisiae expressing Apx toxins in pigs. Vet Immunol Immunopathol 2012. [PMID: 23206402 DOI: 10.1016/j.vetimm.2012.11.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Actinobacillus pleuropneumoniae is a causative agent of porcine pleuropneumonia, a highly contagious endemic disease of pigs worldwide, inducing significant economic losses worldwide. Apx toxins, which are correlated with the virulence of A. pleuropneumoniae, were expressed in Saccharomyces cerevisiae and its possible use as an oral vaccine has been confirmed in our previous studies using a murine model. The present study was undertaken to test the hypothesis that oral immunization using S. cerevisiae expressing either ApxI or ApxII could protect pigs against A. pleuropneumoniae as an effective way of inducing both mucosal and systemic immune responses. The surface-displayed ApxIIA#5 expressing S. cerevisiae was selected as an oral vaccine candidate by finding on induction of higher immune responses in mice after oral vaccination. The surface-displayed ApxIIA#5 expressing S. cerevisiae and the ApxIA expressing S. cerevisiae were developed to serve as an oral vaccine in pigs. The vaccinated pigs showed higher specific IgG- and IgA-related antibody activities than the non-treated control and vector control pigs. Additionally, the induced immune responses were found to protect pigs infected with A. pleuropneumoniae according to the analysis of clinical signs and the gross and microscopic pulmonary lesions. These results suggested that the surface-displayed ApxIIA#5 and ApxIA in S. cerevisiae might be a potential oral vaccine to protect pigs against porcine pleuropneumonia. Thus the present study is expected to contribute to the development of a live oral vaccine against porcine pleuropneumonia as an alternative to current conventional vaccines.
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Affiliation(s)
- Min-Kyoung Shin
- Department of Infectious Disease, College of Veterinary Medicine and Brain Korea 21 Program for Veterinary Science, Seoul National University, Seoul, Republic of Korea
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13
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Cheng S, Zhang M, Li W, Wang Y, Liu Y, He Q. Proteomic analysis of porcine alveolar macrophages infected with porcine circovirus type 2. J Proteomics 2012; 75:3258-69. [DOI: 10.1016/j.jprot.2012.03.039] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Revised: 03/06/2012] [Accepted: 03/23/2012] [Indexed: 01/20/2023]
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Klitgaard K, Friis C, Jensen TK, Angen Ø, Boye M. Transcriptional portrait of Actinobacillus pleuropneumoniae during acute disease--potential strategies for survival and persistence in the host. PLoS One 2012; 7:e35549. [PMID: 22530048 PMCID: PMC3328466 DOI: 10.1371/journal.pone.0035549] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Accepted: 03/21/2012] [Indexed: 11/24/2022] Open
Abstract
Background Gene expression profiles of bacteria in their natural hosts can provide novel insight into the host-pathogen interactions and molecular determinants of bacterial infections. In the present study, the transcriptional profile of the porcine lung pathogen Actinobacillus pleuropneumoniae was monitored during the acute phase of infection in its natural host. Methodology/Principal Findings Bacterial expression profiles of A. pleuropneumoniae isolated from lung lesions of 25 infected pigs were compared in samples taken 6, 12, 24 and 48 hours post experimental challenge. Within 6 hours, focal, fibrino hemorrhagic lesions could be observed in the pig lungs, indicating that A. pleuropneumoniae had managed to establish itself successfully in the host. We identified 237 differentially regulated genes likely to encode functions required by the bacteria for colonization and survival in the host. This group was dominated by genes involved in various aspects of energy metabolism, especially anaerobic respiration and carbohydrate metabolism. Remodeling of the bacterial envelope and modifications of posttranslational processing of proteins also appeared to be of importance during early infection. The results suggested that A. pleuropneumoniae is using various strategies to increase its fitness, such as applying Na+ pumps as an alternative way of gaining energy. Furthermore, the transcriptional data provided potential clues as to how A. pleuropneumoniae is able to circumvent host immune factors and survive within the hostile environment of host macrophages. This persistence within macrophages may be related to urease activity, mobilization of various stress responses and active evasion of the host defenses by cell surface sialylation. Conclusions/Significance The data presented here highlight the importance of metabolic adjustments to host conditions as virulence factors of infecting microorganisms and help to provide insight into the mechanisms behind the efficient colonization and persistence of A. pleuropneumoniae during acute disease.
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Affiliation(s)
- Kirstine Klitgaard
- National Veterinary Institute, Technical University of Denmark, Frederiksberg C, Denmark.
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15
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Liu J, Chen Y, Yuan F, Hu L, Bei W, Chen H. Cloning, expression, and characterization of TonB2 from Actinobacillus pleuropneumoniae and potential use as an antigenic vaccine candidate and diagnostic marker. CANADIAN JOURNAL OF VETERINARY RESEARCH = REVUE CANADIENNE DE RECHERCHE VETERINAIRE 2011; 75:183-190. [PMID: 22210994 PMCID: PMC3122975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 11/09/2009] [Accepted: 08/18/2010] [Indexed: 05/31/2023]
Abstract
In this study the tonB2 gene was cloned from Actinobacillus pleuropneumoniae JL01 (serovar 1) and expressed as a glutathione-S-transferase (GST) fusion protein in Escherichia coli BL21(DE3). The GST fusion protein was recognized by antibodies in serum positive for A. pleuropneumoniae by Western blot analysis. Purified soluble GST-TonB2 was assessed for its ability to protect BALB/c mice against A. pleuropneumoniae infection. Mice were vaccinated with GST-TonB2 subcutaneously and challenged intraperitoneally with either ~4.0 × 10(5) colony-forming units (CFU) or ~1.0 × 10(6) CFU of A. pleuropneumoniae 4074. They were examined daily for 7 d after challenge. The survival rate of the TonB2-vaccinated mice was significant higher than that of the mice given recombinant GST or adjuvant alone. These results demonstrate that A. pleuropneumoniae TonB2 is immunogenic in mice and should be further assessed as a potential candidate for a vaccine against A. pleuropneumoniae infection. In addition, an indirect enzyme-linked immunosorbent assay (ELISA) based on the GST-TonB2 recombinant protein was developed. Compared with the ApxIVA ELISA, the TonB2 ELISA provided earlier detection of antibodies in pigs at various times after vaccination with A. pleuropneumoniae live attenuated vaccine. When compared with an indirect hemagglutination test, the sensitivity and specificity of the TonB2 ELISA were 95% and 88%, respectively. The TonB2 ELISA provides an alternative method for rapid serologic diagnosis of A. pleuropneumoniae infection through antibody screening, which would be especially useful when the infection status or serovar is unknown.
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Affiliation(s)
| | | | | | | | - Weicheng Bei
- Address all correspondence to Dr. Weicheng Bei; telephone/fax: +86-27-87282608; e-mail:
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16
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Chiers K, De Waele T, Pasmans F, Ducatelle R, Haesebrouck F. Virulence factors of Actinobacillus pleuropneumoniae involved in colonization, persistence and induction of lesions in its porcine host. Vet Res 2010; 41:65. [PMID: 20546697 PMCID: PMC2899255 DOI: 10.1051/vetres/2010037] [Citation(s) in RCA: 148] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2009] [Accepted: 06/10/2010] [Indexed: 12/17/2022] Open
Abstract
Actinobacillus pleuropneumoniae is the causative agent of porcine pleuropneumonia. The virulence factors of this microorganism involved in colonization and the induction of lung lesions have been thoroughly studied and some have been well characterized. A. pleuropneumoniae binds preferentially to cells of the lower respiratory tract in a process involving different adhesins and probably biofilm formation. Apx toxins and lipopolysaccharides exert pathogenic effects on several host cells, resulting in typical lung lesions. Lysis of host cells is essential for the bacterium to obtain nutrients from the environment and A. pleuropneumoniae has developed several uptake mechanisms for these nutrients. In addition to persistence in lung lesions, colonization of the upper respiratory tract – and of the tonsils in particular – may also be important for long-term persistent asymptomatic infection. Information on virulence factors involved in tonsillar and nasal cavity colonization and persistence is scarce, but it can be speculated that similar features as demonstrated for the lung may play a role.
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Affiliation(s)
- Koen Chiers
- Department of Pathology, Bacteriology and Poultry Diseases, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium.
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17
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Marois C, Gottschalk M, Morvan H, Fablet C, Madec F, Kobisch M. Experimental infection of SPF pigs with Actinobacillus pleuropneumoniae serotype 9 alone or in association with Mycoplasma hyopneumoniae. Vet Microbiol 2009; 135:283-91. [DOI: 10.1016/j.vetmic.2008.09.061] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2008] [Revised: 08/28/2008] [Accepted: 09/15/2008] [Indexed: 10/21/2022]
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18
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Actinobacillus pleuropneumoniaevaccines: from bacterins to new insights into vaccination strategies. Anim Health Res Rev 2008; 9:25-45. [DOI: 10.1017/s1466252307001338] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
AbstractWith the growing emergence of antibiotic resistance and rising consumer demands concerning food safety, vaccination to prevent bacterial infections is of increasing relevance.Actinobacillus pleuropneumoniaeis the etiological agent of porcine pleuropneumonia, a respiratory disease leading to severe economic losses in the swine industry. Despite all the research and trials that were performed withA. pleuropneumoniaevaccination in the past, a safe vaccine that offers complete protection against all serotypes has yet not reached the market. However, recent advances made in the identification of new potential vaccine candidates and in the targeting of specific immune responses, give encouraging vaccination perspectives. Here, we review past and current knowledge onA. pleuropneumoniaevaccines as well as the newly available genomic tools and vaccination strategies that could be useful in the design of an efficient vaccine againstA. pleuropneumoniaeinfection.
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Lauritzen B, Lykkesfeldt J, Friis C. Evaluation of a single dose versus a divided dose regimen of danofloxacin in treatment of Actinobacillus pleuropneumoniae infection in pigs. Res Vet Sci 2003; 74:271-7. [PMID: 12726746 DOI: 10.1016/s0034-5288(03)00029-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A single versus a divided dose regimen of danofloxacin was evaluated in treatment of porcine Actinobacillus pleuropneumoniae infection using clinical observations combined with biochemical infection markers: C-reactive protein, zinc and ascorbic acid. Twenty hours after experimental infection, the 18 pigs received danofloxacin intravenously as a single dose of 2.5mg/kg or four doses of 0.6 mg/kg administered at 24h intervals. These dosage regimens resulted in similar AUCs of the plasma danofloxacin vs time curve. The maximum concentration was 3.5-fold higher using the single dose regimen, while the time with concentrations above the MIC was 2.5-fold longer using the fractionated regimen. Using the single dose regimen, temperature was normalised 32 h post-infection. In contrast, normalisation was delayed until 44 h post-infection using four low doses and a relapse with elevated temperatures at 52 and 68 h was observed. No other significant differences between the treatments were found, neither regarding clinical, haematological nor biochemical observations. The use of the more convenient single dose regimen was appropriate, as it was at least equivalent to the fractionated regimen.
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Affiliation(s)
- Brian Lauritzen
- Department of Pharmacology and Pathobiology, The Royal Veterinary and Agricultural University, 9 Ridebanevej, 1870 Frederiksberg C, Copenhagen, Denmark.
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20
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Bossé JT, Janson H, Sheehan BJ, Beddek AJ, Rycroft AN, Kroll JS, Langford PR. Actinobacillus pleuropneumoniae: pathobiology and pathogenesis of infection. Microbes Infect 2002; 4:225-35. [PMID: 11880056 DOI: 10.1016/s1286-4579(01)01534-9] [Citation(s) in RCA: 263] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Actinobacillus pleuropneumoniae causes porcine pleuropneumonia, a highly contagious disease for which there is no effective vaccine. This review considers how adhesins, iron-acquisition factors, capsule and lipopolysaccharide, RTX cytotoxins and other potential future vaccine components contribute to colonisation, to avoidance of host clearance mechanisms and to damage of host tissues.
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Affiliation(s)
- Janine T Bossé
- Molecular Infectious Diseases Group, Department of Paediatrics, Faculty of Medicine, Imperial College, St. Mary's Campus, W2 1PG, London, UK.
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21
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Wang FI, Yang JW, Hung SY, Pan IJ. In vitro migratory responses of swine neutrophils to actinobacillus pleuropneumoniae. Exp Anim 2001; 50:139-45. [PMID: 11381617 DOI: 10.1538/expanim.50.139] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Swine neutrophils were quantitatively examined for the direct and indirect migratory responses to Actinobacillus pleuropneumoniae (APP) in vitro and the effects of pseudorabies virus (PrV), frequently co-infecting with APP, were also observed. About 30% of swine neutrophils responded to viable APP, while 3.2% of the neutrophils responded to 0.1% casein which served as the control. The migration of APP was not affected by preincubation of neutrophils with PrV, which inhibited the random migration. When the random migration was normalized to 1, the chemotactic indices for APP, opsonized-APP and casein were 64, 70 and 8.5, respectively. Heat-killed APP or E. coli lipopolysaccharide stimulated the production of interleukin-8 activity by adherent peripheral blood mononuclear cells (PBMC). Preincubation of PBMC with PrV inhibited the production of neutrophil attractant activity when stimulated with heat-killed APP. The results suggested that the direct chemotaxis of neutrophils to viable APP might contribute to early infiltration in Actinobacillus pleuropneumonia, and that PrV might inhibit indirect recruitment of neutrophils to infected lungs by compromising the functions of PBMC.
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Affiliation(s)
- F I Wang
- Department of Veterinary Medicine, National Taiwan University, 142 Chou-San Road, Taipei 106, Taiwan
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22
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Sheehan BJ, Langford PR, Rycroft AN, Kroll JS. [Cu,Zn]-Superoxide dismutase mutants of the swine pathogen Actinobacillus pleuropneumoniae are unattenuated in infections of the natural host. Infect Immun 2000; 68:4778-81. [PMID: 10899887 PMCID: PMC98436 DOI: 10.1128/iai.68.8.4778-4781.2000] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Actinobacillus pleuropneumoniae, the causative agent of porcine pleuropneumonia, contains a periplasmic Cu- and Zn-cofactored superoxide dismutase ([Cu,Zn]-SOD, or SodC) which has the potential, realized in other pathogens, to promote bacterial survival during infection by dismutating host-defense-derived superoxide. Here we describe the construction of a site-specific, [Cu,Zn]-SOD-deficient A. pleuropneumoniae serotype 1 mutant and show that although the mutant is highly sensitive to the microbicidal action of superoxide in vitro, it remains fully virulent in experimental pulmonary infection in pigs.
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Affiliation(s)
- B J Sheehan
- Molecular Infectious Diseases Group, Department of Paediatrics, Imperial College School of Medicine, St. Mary's Campus, London W2 1PG, United Kingdom
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23
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Bossé JT, MacInnes JI. Urease activity may contribute to the ability of Actinobacillus pleuropneumoniae to establish infection. CANADIAN JOURNAL OF VETERINARY RESEARCH = REVUE CANADIENNE DE RECHERCHE VETERINAIRE 2000; 64:145-50. [PMID: 10935879 PMCID: PMC1189605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
The contribution of urease activity to the pathogenesis of Actinobacillus pleuropneumoniae was investigated using 2 different urease-negative transposon mutants of the virulent serotype 1 strain, CM5 Nalr. One mutant, cbiK::Tn10, is deficient in the uptake of nickel, a cofactor required for urease activity. The other mutant, ureG::Tn10, is unable to produce active urease due to mutation of the urease accessory gene, ureG. In aerosol challenge experiments, pigs developed acute pleuropneumonia following exposure to high doses (10(6) cfu/mL) of the parental strain, CM5 Nalr, and to the cbiK::Tn10 mutant. When low dose (10(3) cfu/mL) challenges were used, neither urease-negative mutant was able to establish infection, whereas the parental strain was able to colonize and cause lesions consistent with acute pleuropneumonia in 8 of the 20 pigs challenged. These findings suggest that urease activity may be needed for A. pleuropneumoniae to establish infection in the respiratory tract of pigs.
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Affiliation(s)
- J T Bossé
- Department of Pathobiology, University of Guelph, Ontario
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24
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Hensel A, Huter V, Katinger A, Raza P, Strnistschie C, Roesler U, Brand E, Lubitz W. Intramuscular immunization with genetically inactivated (ghosts) Actinobacillus pleuropneumoniae serotype 9 protects pigs against homologous aerosol challenge and prevents carrier state. Vaccine 2000; 18:2945-55. [PMID: 10825595 DOI: 10.1016/s0264-410x(00)00107-9] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Bacterial ghosts are empty cell envelopes achieved by the expression of a cloned bacteriophage lysis gene and, unlike classical bacterins, suffer no denaturing steps during their production. These properties may lead to a superior presentation of surface antigens to the immune system. Currently available porcine Actinobacillus pleuropneumoniae vaccines afford only minimal protection by decreasing mortality but not morbidity. Pigs which survive infection can still be carriers of the pathogen, so a herd once infected remains infected. Carrier pigs harbour A. pleuropneumoniae in their nasal cavities, in their tonsils, or within lung lesions. A dose-defined nose-only aerosol infection model for pigs was used to study the immunogenic and protective potential of systemic immunization with ghosts made from A. pleuropneumoniae serotype 9 reference strain CVI 13261 against an homologous aerogenous challenge. Pigs were vaccinated twice intramuscularly with a dose of 5x10(9) CFU ghosts (GVPs) or formalin-inactivated A. pleuropneumoniae bacterins (BVPs). After 2 weeks vaccinated pigs and non-vaccinated placebo controls (PCs) were challenged with a dose of 10(9) CFU by aerosol. The protective efficacy of immunization was evaluated by clinical, bacteriological, serological and post-mortem examinations. Bronchoalveolar lavage in pigs was performed during the experiment to obtain lavage samples (BALF) for assessment of local antibodies. Isotype-specific antibody responses in serum and BALF were determined by ELISAs based on whole-cell antigen. Immunization with ghosts did not cause clinical side-effects. After aerosol challenge PCs developed fever and pleuropneumonia. GVPs or BVPs were found to be fully protected against clinical disease or lung lesions in both vaccination groups, whereas colonization of the respiratory tract with A. pleuropneumoniae was only prevented in GVPs. Specific immunoglobins against A. pleuropneumoniae were not detectable in BALF after immunization. A significant systemic increase of IgM, IgA, IgG(Fc'), or IgG(H+L) antibodies reactive with A. pleuropneumoniae was measured in GVPs and BVPs when compared to the non-exposed controls. BVPs reached higher titers of IgG(Fc') and IgG(H+L) than GVPs. However, prevention of carrier state in GVPs coincided with a significant increase of serum IgA when compared to BVPs. These results suggest that immunization with ghosts, that bias antibody populations specific to non-denaturated surface antigens, may be more efficacious in protecting pigs against colonization and infection than bacterins.
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Affiliation(s)
- A Hensel
- Institute of Animal Hygiene and Veterinary Public Health, Veterinary Faculty, University of Leipzig, D-04103 Leipzig, Germany.
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25
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Izeboud CA, Monshouwer M, Witkamp RF, van Miert AS. Suppression of the acute inflammatory response of porcine alveolar- and liver macrophages. Vet Q 2000; 22:26-30. [PMID: 10682384 DOI: 10.1080/01652176.2000.9695019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
During infection and inflammation drug disposition and hepatic metabolism are markedly affected in mammals. Pro-inflammatory mediators play an important role in the suppression of (cytochrome-P450-mediated) drug metabolism. Inflammatory mediators like cytokines, nitric oxide (NO), reactive oxygen species (ROS) and eicosanoids are released by activated macrophages from various sources, including liver and lung. It was the aim of this study to investigate ways to suppress the activation of macrophages during the onset of the inflammatory cascade. Therefore porcine lung and liver macrophages were isolated, and incubated with lipopolysaccharide (LPS) to initiate an acute inflammatory response, represented by the release of high amounts of tumour necrosis factor-alpha (TNF-alpha) into the culture medium. Additionally the primary macrophages were coincubated with phosphodiesterase-IV-(PDE-IV)-inhibitors or beta-adrenoceptor agonists that in previous studies demonstrated strong suppressive effects on TNF-alpha release. Especially the beta-adrenoceptor agonists showed to be very potent TNF-alpha suppressants, which indicates that the beta-adrenoceptor might be an interesting target for suppression of activation of macrophages. This was strengthened by the observation that the beta-adrenoceptor expression was not altered during the onset of the inflammatory cascade.
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Affiliation(s)
- C A Izeboud
- Department of Pharmacology, TNO Pharma, AJ, Zeist, The Netherlands.
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San Gil F, Turner B, Walker MJ, Djordjevic SP, Chin JC. Contribution of adjuvant to adaptive immune responses in mice against Actinobacillus pleuropneumoniae. MICROBIOLOGY (READING, ENGLAND) 1999; 145 ( Pt 9):2595-2603. [PMID: 10517613 DOI: 10.1099/00221287-145-9-2595] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The authors have previously demonstrated that adjuvant-mediated differences in early cellular responses to antigens significantly affect subsequent adaptive immune responses. To investigate further the contribution of adjuvant to adaptive immune responses, outer-membrane proteins (OMP) purified from the respiratory pathogen Actinobacillus pleuropneumoniae, given either alone (antigen group) or complexed with SAMA4 (vaccine group), were injected intradermally into groups of mice. Controls were given PBS. Inclusion of adjuvant did not significantly alter the kinetics of antibody responses against OMP in serum or respiratory tract washings (RTW) over 21 weeks. Re-exposure to OMP at 21 weeks also induced identical recall responses in both immunized groups. However, differences between the responses of the vaccine and antigen groups were apparent when sera and RTW were reacted against OMP and OMP-derived polysaccharide antigens (ODPA). Serum and RTW reactivity against protein antigens was stronger in the vaccine group than in the antigen group. Serum and RTW from the vaccine group also reacted against a greater number of proteins than did the antigen group. Although serum reactivity against ODPA was equivalent for both groups, RTW from the vaccine group reacted only faintly against ODPA compared with the antigen group. The results suggested that shifting of antibody reactivity away from polysaccharide antigens toward protein antigens was an adjuvant-mediated effect. The rapid death of controls following intranasal inoculation confirmed that protection was ultimately dependent on the presence of specific antibodies in the serum and respiratory tract. However, since both groups responded equally to intranasal infection with A. pleuropneumoniae, as seen by the rapid clearance of bacteria from the lungs, the biological significance of any differences between the groups was unclear. Knowledge of the effects of adjuvants may provide a rational basis for adjuvant selection and the ability to manipulate immunological outcomes more precisely.
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Affiliation(s)
- Fernando San Gil
- NSW Agriculture, Elizabeth Macarthur Agricultural Institute, PMB 8, Camden, NSW 2570, Australia1
| | - Bernadette Turner
- NSW Agriculture, Elizabeth Macarthur Agricultural Institute, PMB 8, Camden, NSW 2570, Australia1
| | - Mark J Walker
- Department of Biological Sciences, University of Wollongong, Wollongong, NSW 2522, Australia2
| | - Steven P Djordjevic
- NSW Agriculture, Elizabeth Macarthur Agricultural Institute, PMB 8, Camden, NSW 2570, Australia1
| | - James C Chin
- NSW Agriculture, Elizabeth Macarthur Agricultural Institute, PMB 8, Camden, NSW 2570, Australia1
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Schoevers EJ, van Leengoed LA, Verheijden JH, Niewold TA. Effects of enrofloxacin on porcine phagocytic function. Antimicrob Agents Chemother 1999; 43:2138-43. [PMID: 10471554 PMCID: PMC89436 DOI: 10.1128/aac.43.9.2138] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The interaction between enrofloxacin and porcine phagocytes was studied with clinically relevant concentrations of enrofloxacin. Enrofloxacin accumulated in phagocytes, with cellular concentration/extracellular concentration ratios of 9 for polymorphonuclear leukocytes (PMNs) and 5 for alveolar macrophages (AMs). Cells with accumulated enrofloxacin brought into enrofloxacin-free medium released approximately 80% (AMs) to 90% (PMNs) of their enrofloxacin within the first 10 min, after which no further release was seen. Enrofloxacin affected neither the viability of PMNs and AMs nor the chemotaxis of PMNs at concentrations ranging from 0 to 10 microg/ml. Enrofloxacin (0.5 microg/ml) did not alter the capability of PMNs and AMs to phagocytize fluorescent microparticles or Actinobacillus pleuropneumoniae, Pasteurella multocida, and Staphylococcus aureus. Significant differences in intracellular killing were seen with enrofloxacin at 5x the MIC compared with that for controls not treated with enrofloxacin. PMNs killed all S. aureus isolates in 3 h with or without enrofloxacin. Intracellular S. aureus isolates in AMs were less susceptible than extracellular S. aureus isolates to the bactericidal effect of enrofloxacin. P. multocida was not phagocytosed by PMNs. AMs did not kill P. multocida, and similar intra- and extracellular reductions of P. multocida isolates by enrofloxacin were found. Intraphagocytic killing of A. pleuropneumoniae was significantly enhanced by enrofloxacin at 5x the MIC in both PMNs and AMs. AMs are very susceptible to the A. pleuropneumoniae cytotoxin. This suggests that in serologically naive pigs the enhancing effect of enrofloxacin on the bactericidal action of PMNs may have clinical relevance.
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Affiliation(s)
- E J Schoevers
- Department of Herd Health and Reproduction, University of Utrecht, Utrecht, The Netherlands
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28
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Solano GI, Bautista E, Molitor TW, Segales J, Pijoan C. Effect of porcine reproductive and respiratory syndrome virus infection on the clearance of Haemophilus parasuis by porcine alveolar macrophages. CANADIAN JOURNAL OF VETERINARY RESEARCH = REVUE CANADIENNE DE RECHERCHE VETERINAIRE 1998; 62:251-6. [PMID: 9798089 PMCID: PMC1189490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Porcine reproductive and respiratory syndrome virus (PRRSV) infection in young piglets is frequently associated with secondary infection due to various pathogens, especially those of the respiratory tract. One of the most important mechanisms in respiratory diseases is related to the alteration of function of porcine alveolar macrophages (PAMs). The objective of this study was to determine how PRRS virus infection affects the capabilities of PAMs in the phagocytosis and destruction of Haemophilus parasuis. Phagocytosis percentages were determined in vitro and ex vivo, after collected PAMs were directly exposed to the virus of if PAMs were collected from piglets previously infected with PRRSV. In vitro experiments demonstrated that H. parasuis uptake by PAMs is only increased in the early stages of PRRSV infection (2 h post-infection). In contrast, in the ex vivo experiments it was shown that PAMs from PRRSV-infected piglets do not seem to change in their phagocytic rate until the later stages of infection. Together with a decrease in the phagocytic rate, a marked decrease in the functional ability of PAMs to kill bacteria was observed 7 d post-infection. It is hypothesized that when animals are exposed to PRRSV, there is a marked decrease in the functional ability of PAMs to kill bacteria through the release of superoxide anion, indicating a possible negative effect of the virus, at least at the macrophage level.
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Affiliation(s)
- G I Solano
- College of Veterinary Medicine, University of Minnesota, St. Paul 55108, USA
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Agersø H, Friis C, Nielsen JP. Penetration of amoxycillin to the respiratory tract tissues and secretions in Actinobacillus pleuropneumoniae infected pigs. Res Vet Sci 1998; 64:251-7. [PMID: 9690612 DOI: 10.1016/s0034-5288(98)90134-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The pharmokinetic properties of amoxycillin, and its penetration into respiratory tract tissue, were determined in 18 Actinobacillus pleuropneumoniae infected pigs, after a single i.v. dose of 8.6 mg amoxycillin kg(-1) bodyweight. Pleuropneumoniae was produced experimentally in pigs by an aerosol infection model. The infection created a homogeneous response, characterised by depression of breathing and increased body temperature. The clinical symptoms were accompanied by increased haptoglobin levels and circulating white blood cell counts. At necropsy the findings were characterised by a bilateral fibrinous pleuropneumonia. Twenty hours after infection, the pigs were administered amoxycillin i.v. The plasma concentration-time curve was described by a three compartment open model. The mean residence time and the elimination half-life were 1.5 and 3.4 hours, respectively. The steady-state volume of distribution was 0.67 litres kg(-1), and the clearance was 0.46 litres kg(-1) hour(-1). There were no significant differences between these values and those reported previously for healthy pigs. The concentration of amoxycillin in bronchial secretions, lung tissue and diseased lung tissue peaked two hours after intravenous drug administration, while amoxycillin concentration in pleural fluid, lymph nodes and tonsil tissue peaked at the first sampling point one hour after drug administration. The concentration of amoxycillin in secretions and tissue decreased by a slower rate than amoxycillin concentration in plasma, resulting in an increasing tissue-to-plasma concentration ratio. The distribution ratios (AUCtissue/AUCplasma) was 0.53 for bronchial secretions, 0.44 for pneumonic lung tissue, 0.42 for lung tissue, 1.04 for pleural fluid, 0.58 for lymph nodes and 0.37 for tonsil tissue. The distribution of amoxycillin to secretions was increased compared with that previously reported for healthy pigs, while only minor changes were observed in lung tissue.
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Affiliation(s)
- H Agersø
- Department of Pharmacology and Pathobiology, Royal Veterinary and Agricultural University, Frederiksberg C, Denmark
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Wattrang E, Wallgren P, Fossum C. Actinobacillus pleuropneumonia serotype 2--effects on the interferon-alpha production of porcine leukocytes in vivo and in vitro. Comp Immunol Microbiol Infect Dis 1998; 21:135-54. [PMID: 9611683 DOI: 10.1016/s0147-9571(97)00025-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Effects of a bacterial infection on the IFN-alpha production in vivo and in vitro were studied in eight specific pathogen free pigs experimentally infected with Actinobacillus pleuropneumoniae. Clinically, the experimental infection was manifested as a febrile stage which lasted approximately one week and by signs of respiratory disease. The Aujeszky's disease virus (ADV) induced IFN-alpha production, assessed in whole blood cultures, was increased for the infected pigs during the febrile stage. Potentiating effects on the IFN-alpha production could be transferred to cultures of purified peripheral blood mononuclear cells with sera collected from the infected pigs during this period of time. Although the experimental infection with A. pleuropneumoniae did not induce any detectable amounts of IFN-alpha in serum or nasal secretion, both a phenol-extract and a heat-inactivated preparation of the bacteria induced low levels of IFN-alpha in cultures of purified PBMC. The interferogenic structures of the bacteria were not identified but there were indications that the bacteria induced IFN-alpha production in the same cell type as ADV.
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Affiliation(s)
- E Wattrang
- Department of Veterinary Microbiology, Swedish University of Agricultural Sciences, Uppsala, Sweden
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Haesebrouck F, Chiers K, Van Overbeke I, Ducatelle R. Actinobacillus pleuropneumoniae infections in pigs: the role of virulence factors in pathogenesis and protection. Vet Microbiol 1997; 58:239-49. [PMID: 9453134 DOI: 10.1016/s0378-1135(97)00162-4] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
This paper discusses the possible role of virulence factors of Actinobacillus pleuropneumoniae in pathogenesis and protection. Special attention is paid to the Apx-exotoxins and to adhesins.
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Affiliation(s)
- F Haesebrouck
- Department of Pathology, Bacteriology and Poultry Diseases, Faculty of Veterinary Medicine, University of Ghent, Merelbeke, Belgium.
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Kamp EM, Stockhofe-Zurwieden N, van Leengoed LA, Smits MA. Endobronchial inoculation with Apx toxins of Actinobacillus pleuropneumoniae leads to pleuropneumonia in pigs. Infect Immun 1997; 65:4350-4. [PMID: 9317048 PMCID: PMC175624 DOI: 10.1128/iai.65.10.4350-4354.1997] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
To establish the role of the Apx toxins in the pathogenesis of porcine pleuropneumonia, specific-pathogen-free pigs were inoculated deeply endobronchially with either culture filtrates of Actinobacillus pleuropneumoniae serotype 8 or 9, culture filtrates depleted of the Apx toxins by affinity chromatography, depleted culture filtrate supplemented with purified recombinant Apx toxins (rApx), or purified rApx toxins alone. Results of these experiments indicate that ApxI, ApxIII, and, to a lesser extent, ApxII are the bacterial factors that trigger the development of clinical symptoms and lung lesions typical for porcine pleuropneumonia.
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Affiliation(s)
- E M Kamp
- Department of Bacteriology, Institute for Animal Science and Health, Lelystad, The Netherlands.
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Tascón Cabrero RI, Vázquez-Boland JA, Gutiérrez CB, Rodríguez-Barbosa JI, Rodríguez-Ferri EF. Actinobacillus pleuropneumoniae does not require urease activity to produce acute swine pleuropneumonia. FEMS Microbiol Lett 1997; 148:53-7. [PMID: 9066110 DOI: 10.1111/j.1574-6968.1997.tb10266.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The role in virulence of Actinobacillus pleuropneumoniae urease activity was investigated. A urease-negative mutant was isolated following transposon mutagenesis with a mini-Tn10 derivative. Both the parent strain and the urease-negative mutant exhibited identical LD50 values in a murine infection model. Pig challenge confirmed that the urease-negative mutant was fully virulent, since experimental inoculation with 5 x 10(7) colony forming units resulted in an acute disease indistinguishable from that produced by the wild-type strain at the same dose. Our results demonstrate that urease activity is not required for the development of acute pleuropneumonia.
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Affiliation(s)
- R I Tascón Cabrero
- Departamento de Patologia Animal-Sanidad Animal, Facultad de Veterinaria, Universidad de León, Spain.
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Furesz SE, Mallard BA, Bossé JT, Rosendal S, Wilkie BN, MacInnes JI. Antibody- and cell-mediated immune responses of Actinobacillus pleuropneumoniae-infected and bacterin-vaccinated pigs. Infect Immun 1997; 65:358-65. [PMID: 9009283 PMCID: PMC174603 DOI: 10.1128/iai.65.2.358-365.1997] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Current porcine pleuropneumonia bacterins afford only partial protection by decreasing mortality but not morbidity. In order to better understand the type(s) of immune response associated with protection, antibody- and cell-mediated immune responses (CMIR) were compared for piglets before and after administration of a commercial bacterin, which confers partial protection, or a low-dose (10(5) CFU/ml) aerosol challenge with Actinobacillus pleuropneumoniae CM5 (LD), which induces complete protection. Control groups received phosphate-buffered saline or adjuvant. Serum antibody response, antibody avidity, delayed-type hypersensitivity (DTH), and lymphocyte blastogenic responses were measured and compared among treatment groups to the lipopolysaccharide (LPS), capsular polysaccharide (CPS), hemolysin (HLY), and outer membrane proteins (OMP) of A. pleuropneumoniae. Peripheral blood lymphocytes and sera were collected prior to and following primary and secondary immunization-infection and high-dose A. pleuropneumoniae CM5 (10(7) CFU/ml) aerosol challenge. Serum antibody and DTH, particularly that to HLY, differed significantly between treatment groups, and increases were associated with protection. LD-infected piglets had higher antibody responses (P < or = 0.01) and antibody avidity (P < or = 0.10) than bacterin-vaccinated and control groups. Anti-HLY antibodies were consistently associated with protection, whereas anti-LPS and anti-CPS antibodies were not. LD-infected animals had higher DTH responses, particularly to HLY, than bacterin-vaccinated pigs (P < or = 0.03). The LD-infected group maintained consistent blastogenic responses to HLY, LPS, CPS, and OMP over the course of infection, unlike the bacterin-vaccinated and control animals. These data suggest that the immune responses induced by a commercial bacterin are very different from those induced by LD aerosol infection and that current bacterins may be modified, for instance, by addition of HLY, so as to stimulate responses which better reflect those induced by LD infection.
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Affiliation(s)
- S E Furesz
- Department of Pathobiology, Ontario Veterinary College, University of Guelph, Canada
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Hensel A, Stockhofe-Zurwieden N, Ganter M, Petzoldt K. Aerosol exposure of pigs to viable or inactivated Actinobacillus pleuropneumoniae serotype 9 induces antibodies in bronchoalveolar lining fluids and serum, and protects against homologous challenge. Vet Microbiol 1995; 47:27-41. [PMID: 8604553 DOI: 10.1016/0378-1135(95)00106-k] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A dose-defined nose-only inhalation system for pigs was used to study the immunogenic and protective potentials of a single aerosol application of viable or killed Actinobacillus pleuropneumoniae serotype 9. Respiratory volumes were measured for each pig to calculate inhaled individual doses. Eight pigs inhaled 107 CFU A. pleuropneumoniae CVI 13261 reference strain for serotype 9. Another eight pigs received an identical dose of killed actinobacilli. After three weeks the pigs and nonexposed controls were challenged with 108 CFU of the homologous strain by aerosol. Bronchoalveolar lavage (BALF) in pigs was performed during the experiment to obtain lavage samples for assessment of local antibodies. Isotype-specific antibody responses in serum and BAL fluids were measured by ELISAs based on whole-cell antigens. The protective efficacy of aerosol immunization was evaluated by clinical and post-mortem examinations. The controls developed fever and severe pleuropneumonia, whereas previously exposed pigs had less fever and less extensive gross pulmonary lesions. After the first aerosol exposure pulmonary IgM, and IgG antibodies reactive with A. pleuropneumoniae increased significantly in both aerosol exposed groups. IgA in BALF and serum concentrations of each Ig class were significantly increased in the group exposed to viable bacteria when compared to the non-exposed controls. After aerosol challenge a pronounced increase of systemic and pulmonary IgA, IgM, and IgG antibodies was detected in both exposure groups. Aerosol application of whole-cell A. pleuropneumoniae bacterins induced similar protective effects against aerosol challenge infection as administration of an identical dose of viable bacteria. Inhalation of A. pleuropneumoniae may lead to asymptomatic carriers in some pigs that could spread the disease under field conditions.
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Affiliation(s)
- A Hensel
- Institute of Microbiology and Genetics, Biocentre, University of Vienna, Austria
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Cruijsen T, van Leengoed LA, Ham-Hoffies M, Verheijden JH. Convalescent pigs are protected completely against infection with a homologous Actinobacillus pleuropneumoniae strain but incompletely against a heterologous-serotype strain. Infect Immun 1995; 63:2341-3. [PMID: 7768619 PMCID: PMC173307 DOI: 10.1128/iai.63.6.2341-2343.1995] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
To study whether Actinobacillus pleuropneumoniae induces a species-specific immunity, we infected pigs in the left lung with serotype 3 or 9 and after 3 weeks we infected their right lungs with serotype 9. Convalescent pigs were protected against homologous strain reinfection, but after heterologous strain reinfection the degree of protection varied. Neutralizing antibodies were not essential for protection.
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Affiliation(s)
- T Cruijsen
- Department of Herd Health and Reproduction, Faculty of Veterinary Medicine, Utrecht University, The Netherlands
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Tascón RI, Vázquez-Boland JA, Gutiérrez-Martín CB, Rodríguez-Barbosa I, Rodríguez-Ferri EF. The RTX haemolysins ApxI and ApxII are major virulence factors of the swine pathogen Actinobacillus pleuropneumoniae: evidence from mutational analysis. Mol Microbiol 1994; 14:207-16. [PMID: 7830567 DOI: 10.1111/j.1365-2958.1994.tb01282.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The involvement of the RTX haemolysins (ApxI and ApxII) of the swine pathogen Actinobacillus pleuropneumoniae in virulence was investigated using haemolysin-deficient mutants constructed by a mini-Tn10 mutagenesis procedure. Two types of haemolysin mutant with single insertions of the transposon were obtained from a serotype 1 strain producing both ApxI and ApxII. One presented a complete loss of haemolytic activity because of the absence of ApxI and ApxII production. The other displayed weaker haemolysis than the wild type and produced only ApxII. The chromosomal regions flanking mini-Tn10 were cloned and sequenced. In the non-haemolytic mutant, the transposon had inserted in apxIB, a gene involved in the exportation of ApxI and ApxII toxins. The weakly haemolytic mutant resulted from the disruption of the structural gene for ApxI. Both mutations in the apxI operon were associated with a significant loss of virulence for mice and pigs, demonstrating that haemolysins are involved in A. pleuropneumoniae pathogenicity. The non-haemolytic mutant was apathogenic and the weakly haemolytic mutant retained some virulence for pigs, suggesting that both ApxI and ApxII are needed for full virulence.
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Affiliation(s)
- R I Tascón
- Unidad de Microbiología e Inmunología, Facultad de Veterinaria, Universidad de León, Spain
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