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Xu K, Zhao Q, Jiang HZ, Mou XR, Chang YF, Cao YQ, Miao C, Wu R, Wen YP, Huang XB, Yan QG, Du SY, Cao SJ. Molecular and functional characterization of HtrA protein in Actinobacillus pleuropneumoniae. Vet Microbiol 2021; 257:109058. [PMID: 33862332 DOI: 10.1016/j.vetmic.2021.109058] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Accepted: 03/20/2021] [Indexed: 11/15/2022]
Abstract
Actinobacillus pleuropneumoniae (A.pleuropneumoniae) causes serious economic loss for the swine industry. A high-temperature requirements A (HtrA)-like protease and its homologs have been reported to be involved in protein quality control and expression of important immunoprotective antigens in many pathogens. In this study, we showed that HtrA of A.pleuropneumoniae exhibited both chaperone and proteolytic activities. Moreover, Outer membrane protein P5 (OmpP5) in A.pleuropneumoniae and Heat shock protein 90 (Hsp90) in porcine lung tissues were first discovered and identified as specific proteolytic substrates for rHtrA. The maximum cleavage activity occurs at 50 ℃ in a time-dependent manner. In addition, rHtrA mainly induced IgG 2a subtype of IgG and Th1 (IFN-γ, IL-2) response in a mice model, and promoted a significant proliferation of spleen lymphocytes compare with negative control (P < 0.05). The survival rates of 37.5 % were observed against A.pleuropneumoniae strain. Together, these data demonstrate that rHtrA plays a multi-functional role in A.pleuropneumoniae.
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Affiliation(s)
- Kui Xu
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Qin Zhao
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Hong-Ze Jiang
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Xin-Ran Mou
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Yung-Fu Chang
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, United States
| | - Yu-Qin Cao
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Chang Miao
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Rui Wu
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Yi-Ping Wen
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Xiao-Bo Huang
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Qi-Gui Yan
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Sen-Yan Du
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - San-Jie Cao
- Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.
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Discovery and Contribution of Nontypeable Haemophilus influenzae NTHI1441 to Human Respiratory Epithelial Cell Invasion. Infect Immun 2019; 87:IAI.00462-19. [PMID: 31427451 DOI: 10.1128/iai.00462-19] [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: 06/13/2019] [Accepted: 07/25/2019] [Indexed: 11/20/2022] Open
Abstract
Nontypeable Haemophilus influenzae (NTHi) is the primary cause of bacterially induced acute exacerbations of chronic obstructive pulmonary disease (COPD). NTHi adheres to and invades host respiratory epithelial cells as a means to persist in the lower airways of adults with COPD. Therefore, we mined the genomes of NTHi strains isolated from the airways of adults with COPD to identify novel proteins to investigate their role in adherence and invasion of human respiratory epithelial cells. An isogenic knockout mutant of the open reading frame NTHI1441 showed a 76.6% ± 5.5% reduction in invasion of human bronchial and alveolar epithelial cells at 1, 3, and 6 h postinfection. Decreased invasion of the NTHI1441 mutant was independent of either intracellular survival or adherence to cells. NTHI1441 is conserved among NTHi genomes. Results of whole-bacterial-cell enzyme-linked immunosorbent assay (ELISA) and flow cytometry experiments identified that NTHI1441 has epitopes expressed on the bacterial cell surface. Adults with COPD develop increased serum IgG against NTHI1441 after experiencing an exacerbation with NTHi. This study reveals NTHI1441 as a novel NTHi virulence factor expressed during infection of the COPD lower airways that contributes to invasion of host respiratory epithelial cells. The role in host cell invasion, conservation among strains, and expression of surface-exposed epitopes suggest that NTHI1441 is a potential target for preventative and therapeutic interventions for disease caused by NTHi.
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Rahman MS, Rahman MK, Saha S, Kaykobad M, Rahman MS. Antigenic: An improved prediction model of protective antigens. Artif Intell Med 2019; 94:28-41. [DOI: 10.1016/j.artmed.2018.12.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 10/31/2018] [Accepted: 12/28/2018] [Indexed: 10/27/2022]
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Recognition of conserved antigens by Th17 cells provides broad protection against pulmonary Haemophilus influenzae infection. Proc Natl Acad Sci U S A 2018; 115:E7149-E7157. [PMID: 29987031 DOI: 10.1073/pnas.1802261115] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Nontypeable Haemophilus influenzae (NTHi) is a major cause of community acquired pneumonia and exacerbation of chronic obstructive pulmonary disease. A current effort in NTHi vaccine development has focused on generating humoral responses and has been greatly impeded by antigenic variation among the numerous circulating NTHi strains. In this study, we showed that pulmonary immunization of mice with killed NTHi generated broad protection against lung infection by different strains. While passive transfer of immune antibodies protected only against the homologous strain, transfer of immune T cells conferred protection against both homologous and heterologous strains. Further characterization revealed a strong Th17 response that was cross-reactive with different NTHi strains. Responding Th17 cells recognized both cytosolic and membrane-associated antigens, while immune antibodies preferentially responded to surface antigens and were highly strain specific. We further identified several conserved proteins recognized by lung Th17 cells during NTHi infection. Two proteins yielding the strongest responses were tested as vaccine candidates by immunization of mice with purified proteins plus an adjuvant. Immunization induced antigen-specific Th17 cells that recognized different strains and, upon adoptive transfer, conferred protection. Furthermore, immunized mice were protected against challenge with not only NTHi strains but also a fully virulent, encapsulated strain. Together, these results show that the immune mechanism of cross-protection against pneumonia involves Th17 cells, which respond to a broad spectrum of antigens, including those that are highly conserved among NTHi strains. These mechanistic insights suggest that inclusion of Th17 antigens in subunit vaccines offers the advantage of inducing broad protection and complements the current antibody-based approaches.
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Giebink GS, Bakaletz LO, Barenkamp SJ, Eskola J, Green B, Gu XX, Harada T, Heikkinen T, Karma P, Klein JO, Kurono Y, Mogi G, Murphy TF, Ogra PL, Patel JA, Suzuki M, Yamanaka N. 7. Vaccine. Ann Otol Rhinol Laryngol 2016. [DOI: 10.1177/00034894021110s310] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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HtrA Is Important for Stress Resistance and Virulence in Haemophilus parasuis. Infect Immun 2016; 84:2209-2219. [PMID: 27217419 PMCID: PMC4962635 DOI: 10.1128/iai.00147-16] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 05/12/2016] [Indexed: 02/06/2023] Open
Abstract
Haemophilus parasuis is an opportunistic pathogen that causes Glässer's disease in swine, with polyserositis, meningitis, and arthritis. The high-temperature requirement A (HtrA)-like protease, which is involved in protein quality control, has been reported to be a virulence factor in many pathogens. In this study, we showed that HtrA of H. parasuis (HpHtrA) exhibited both chaperone and protease activities. Finally, nickel import ATP-binding protein (NikE), periplasmic dipeptide transport protein (DppA), and outer membrane protein A (OmpA) were identified as proteolytic substrates for HpHtrA. The protease activity reached its maximum at 40°C in a time-dependent manner. Disruption of the htrA gene from strain SC1401 affected tolerance to temperature stress and resistance to complement-mediated killing. Furthermore, increased autoagglutination and biofilm formation were detected in the htrA mutant. In addition, the htrA mutant was significantly attenuated in virulence in the murine model of infection. Together, these data demonstrate that HpHtrA plays an important role in the virulence of H. parasuis.
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Khan MN, Ren D, Kaur R, Basha S, Zagursky R, Pichichero ME. Developing a vaccine to prevent otitis media caused by nontypeable Haemophilus influenzae. Expert Rev Vaccines 2016; 15:863-78. [PMID: 26894630 DOI: 10.1586/14760584.2016.1156539] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Nontypeable Haemophilus influenzae (NTHi) is a predominant organism of the upper respiratory nasopharyngeal microbiota. Its disease spectrum includes otitis media, sinusitis, non-bacteremic pneumonia and invasive infections. Protein-based vaccines to prevent NTHi infections are needed to alleviate these infections in children and vulnerable populations such as the elderly and those with chronic obstructive pulmonary disease (COPD). One NTHi protein is included in a pneumococcal conjugate vaccine and has been shown to provide efficacy. Our lab has been interested in understanding the immunogenicity of NTHi vaccine candidates P6, protein D and OMP26 for preventing acute otitis media in young children. We expect that continued investigation and progress in the development of an efficacious protein based vaccine against NTHi infections is achievable in the near future.
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Affiliation(s)
- M Nadeem Khan
- a Center for Infectious Disease and Immunology , Rochester General Hospital Research Institute , Rochester , NY , USA
| | - Dabin Ren
- a Center for Infectious Disease and Immunology , Rochester General Hospital Research Institute , Rochester , NY , USA
| | - Ravinder Kaur
- a Center for Infectious Disease and Immunology , Rochester General Hospital Research Institute , Rochester , NY , USA
| | - Saleem Basha
- a Center for Infectious Disease and Immunology , Rochester General Hospital Research Institute , Rochester , NY , USA
| | - Robert Zagursky
- a Center for Infectious Disease and Immunology , Rochester General Hospital Research Institute , Rochester , NY , USA
| | - Michael E Pichichero
- a Center for Infectious Disease and Immunology , Rochester General Hospital Research Institute , Rochester , NY , USA
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Samazan F, Rokbi B, Seguin D, Telles F, Gautier V, Richarme G, Chevret D, Varela PF, Velours C, Poquet I. Production, secretion and purification of a correctly folded staphylococcal antigen in Lactococcus lactis. Microb Cell Fact 2015; 14:104. [PMID: 26178240 PMCID: PMC4502909 DOI: 10.1186/s12934-015-0271-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 05/08/2015] [Indexed: 11/23/2022] Open
Abstract
Background Lactococcus lactis, a lactic acid bacterium traditionally used to ferment milk and manufacture cheeses, is also, in the biotechnology field, an interesting host to produce proteins of medical interest, as it is “Generally Recognized As Safe”. Furthermore, as L. lactis naturally secretes only one major endogenous protein (Usp45), the secretion of heterologous proteins in this species facilitates their purification from a protein-poor culture medium. Here, we developed and optimized protein production and secretion in L. lactis to obtain proteins of high quality, both correctly folded and pure to a high extent. As proteins to be produced, we chose the two transmembrane members of the HtrA protease family in Staphylococcus aureus, an important extra-cellular pathogen, as these putative surface-exposed antigens could constitute good targets for vaccine development. Results A recombinant ORF encoding a C-terminal, soluble, proteolytically inactive and tagged form of each staphylococcal HtrA protein was cloned into a lactococcal expression-secretion vector. After growth and induction of recombinant gene expression, L. lactis was able to produce and secrete each recombinant rHtrA protein as a stable form that accumulated in the culture medium in similar amounts as the naturally secreted endogenous protein, Usp45. L. lactis growth in fermenters, in particular in a rich optimized medium, led to higher yields for each rHtrA protein. Protein purification from the lactococcal culture medium was easily achieved in one step and allowed recovery of highly pure and stable proteins whose identity was confirmed by mass spectrometry. Although rHtrA proteins were monomeric, they displayed the same secondary structure content, thermal stability and chaperone activity as many other HtrA family members, indicating that they were correctly folded. rHtrA protein immunogenicity was established in mice. The raised polyclonal antibodies allowed studying the expression and subcellular localization of wild type proteins in S. aureus: although both proteins were expressed, only HtrA1 was found to be, as predicted, exposed at the staphylococcal cell surface suggesting that it could be a better candidate for vaccine development. Conclusions In this study, an efficient process was developed to produce and secrete putative staphylococcal surface antigens in L. lactis and to purify them to homogeneity in one step from the culture supernatant. This allowed recovering fully folded, stable and pure proteins which constitute promising vaccine candidates to be tested for protection against staphylococcal infection. L. lactis thus proved to be an efficient and competitive cell factory to produce proteins of high quality for medical applications. Electronic supplementary material The online version of this article (doi:10.1186/s12934-015-0271-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Frédéric Samazan
- INRA, UMR1319 Micalis (Microbiologie de l'Alimentation au service de la Santé), Domaine de Vilvert, 78352, Jouy-en-Josas Cedex, France. .,Institut Curie/CNRS, UMR3244, 25 rue d'Ulm, 75248, Paris Cedex 05, France.
| | - Bachra Rokbi
- Sanofi Pasteur, Campus Mérieux, 1541 avenue Marcel Mérieux, 69280, Marcy L'Etoile, France.
| | - Delphine Seguin
- Sanofi Pasteur, Campus Mérieux, 1541 avenue Marcel Mérieux, 69280, Marcy L'Etoile, France.
| | - Fabienne Telles
- Sanofi Pasteur, Campus Mérieux, 1541 avenue Marcel Mérieux, 69280, Marcy L'Etoile, France.
| | - Valérie Gautier
- Stress molecules, Institut Jacques Monod, Université Paris 7, 15 rue Hélène Brion, 75013, Paris, France.
| | - Gilbert Richarme
- Stress molecules, Institut Jacques Monod, Université Paris 7, 15 rue Hélène Brion, 75013, Paris, France.
| | - Didier Chevret
- INRA, UMR1319 Micalis (Microbiologie de l'Alimentation au service de la Santé), Domaine de Vilvert, 78352, Jouy-en-Josas Cedex, France.
| | | | | | - Isabelle Poquet
- INRA, UMR1319 Micalis (Microbiologie de l'Alimentation au service de la Santé), Domaine de Vilvert, 78352, Jouy-en-Josas Cedex, France. .,LPBA, Institut Pasteur, Bât. Calmette, 75015, Paris, France.
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Ullmann AJ, Russell TM, Dolan MC, Williams M, Hojgaard A, Weiner ZP, Johnson BJB. Evaluation of Borrelia burgdorferi BbHtrA Protease as a Vaccine Candidate for Lyme Borreliosis in Mice. PLoS One 2015; 10:e0128868. [PMID: 26076465 PMCID: PMC4468080 DOI: 10.1371/journal.pone.0128868] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 05/03/2015] [Indexed: 01/11/2023] Open
Abstract
Borrelia burgdorferi synthesizes an HtrA protease (BbHtrA) which is a surface-exposed, conserved protein within Lyme disease spirochetes with activity toward CheX and BmpD of Borrelia spp, as well as aggrecan, fibronectin and proteoglycans found in skin, joints and neural tissues of vertebrates. An antibody response against BbHtrA is observed in Lyme disease patients and in experimentally infected laboratory mice and rabbits. Given the surface location of BbHtrA on B. burgdorferi and its ability to elicit an antibody response in infected hosts, we explored recombinant BbHtrA as a potential vaccine candidate in a mouse model of tick-transmitted Lyme disease. We immunized mice with two forms of BbHtrA: the proteolytically active native form and BbHtrA ablated of activity by a serine to alanine mutation at amino acid 226 (BbHtrA(S226A)). Although inoculation with either BbHtrA or BbHtrA(S226A) produced high-titer antibody responses in C3H/HeJ mice, neither antigen was successful in protecting mice from B. burgdorferi challenge. These results indicate that the search for novel vaccine candidates against Lyme borreliosis remains a challenge.
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Affiliation(s)
- Amy J. Ullmann
- Bacterial Diseases Branch, Division of Vector Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO, United States of America
- * E-mail:
| | - Theresa M. Russell
- Bacterial Diseases Branch, Division of Vector Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO, United States of America
| | - Marc C. Dolan
- Bacterial Diseases Branch, Division of Vector Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO, United States of America
| | - Martin Williams
- Bacterial Diseases Branch, Division of Vector Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO, United States of America
| | - Andrias Hojgaard
- Bacterial Diseases Branch, Division of Vector Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO, United States of America
| | - Zachary P. Weiner
- Bacterial Diseases Branch, Division of Vector Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO, United States of America
| | - Barbara J. B. Johnson
- Bacterial Diseases Branch, Division of Vector Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO, United States of America
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Vaccines for Nontypeable Haemophilus influenzae: the Future Is Now. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2015; 22:459-66. [PMID: 25787137 DOI: 10.1128/cvi.00089-15] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Infections due to nontypeable Haemophilus influenzae result in enormous global morbidity in two clinical settings: otitis media in children and respiratory tract infections in adults with chronic obstructive pulmonary disease (COPD). Recurrent otitis media affects up to 20% of children and results in hearing loss, delays in speech and language development and, in developing countries, chronic suppurative otitis media. Infections in people with COPD result in clinic and emergency room visits, hospital admissions, and respiratory failure. An effective vaccine would prevent morbidity, help control health care costs, and reduce antibiotic use, a major contributor to the global crisis in bacterial antibiotic resistance. The widespread use of the pneumococcal conjugate vaccines is causing a relative increase in H. influenzae otitis media. The partial protection against H. influenzae otitis media induced by the pneumococcal H. influenzae protein D conjugate vaccine represents a proof of principle of the feasibility of a vaccine for nontypeable H. influenzae. An ideal vaccine antigen should be conserved among strains, have abundant epitopes on the bacterial surface, be immunogenic, and induce protective immune responses. Several surface proteins of H. influenzae have been identified as potential vaccine candidates and are in various stages of development. With continued research, progress toward a broadly effective vaccine to prevent infections caused by nontypeable H. influenzae is expected over the next several years.
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Roier S, Blume T, Klug L, Wagner GE, Elhenawy W, Zangger K, Prassl R, Reidl J, Daum G, Feldman MF, Schild S. A basis for vaccine development: Comparative characterization of Haemophilus influenzae outer membrane vesicles. Int J Med Microbiol 2014; 305:298-309. [PMID: 25592265 DOI: 10.1016/j.ijmm.2014.12.005] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2014] [Revised: 12/09/2014] [Accepted: 12/14/2014] [Indexed: 11/29/2022] Open
Abstract
Outer membrane vesicles (OMVs) are spherical and bilayered particles that are naturally released from the outer membrane (OM) of Gram-negative bacteria. They have been proposed to possess several biological roles in pathogenesis and interbacterial interactions. Additionally, OMVs have been suggested as potential vaccine candidates against infections caused by pathogenic bacteria like Haemophilus influenzae, a human pathogen of the respiratory tract. Unfortunately, there is still a lack of fundamental knowledge regarding OMV biogenesis, protein sorting into OMVs, OMV size and quantity, as well as OMV composition in H. influenzae. Thus, this study comprehensively characterized and compared OMVs and OMs derived from heterologous encapsulated as well as nonencapsulated H. influenzae strains. Semiquantitative immunoblot analysis revealed that certain OM proteins are enriched or excluded in OMVs suggesting the presence of regulated protein sorting mechanisms into OMVs as well as interconnected OMV biogenesis mechanisms in H. influenzae. Nanoparticle tracking analysis, transmission electron microscopy, as well as protein and lipooligosaccharide quantifications demonstrated that heterologous H. influenzae strains differ in their OMV size and quantity. Lipidomic analyses identified palmitic acid as the most abundant fatty acid, while phosphatidylethanolamine was found to be the most dominant phospholipid present in OMVs and the OM of all strains tested. Proteomic analysis confirmed that H. influenzae OMVs contain vaccine candidate proteins as well as important virulence factors. These findings contribute to the understanding of OMV biogenesis as well as biological roles of OMVs and, in addition, may be important for the future development of OMV based vaccines against H. influenzae infections.
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Affiliation(s)
- Sandro Roier
- Institute of Molecular Biosciences, University of Graz, NAWI Graz, BioTechMed-Graz, Humboldtstraße 50, A-8010 Graz, Austria
| | - Thomas Blume
- Institute of Molecular Biosciences, University of Graz, NAWI Graz, BioTechMed-Graz, Humboldtstraße 50, A-8010 Graz, Austria
| | - Lisa Klug
- Institute of Biochemistry, Graz University of Technology, NAWI Graz, BioTechMed-Graz, Petersgasse 12/2, A-8010 Graz, Austria
| | - Gabriel E Wagner
- Institute of Chemistry/Organic and Bioorganic Chemistry, University of Graz, NAWI Graz, BioTechMed-Graz, Heinrichstraße 28, A-8010 Graz, Austria
| | - Wael Elhenawy
- Alberta Glycomics Centre, Department of Biological Sciences, University of Alberta, CW405 Biological Sciences Building, Edmonton, AB, Canada T6G 2E9
| | - Klaus Zangger
- Institute of Chemistry/Organic and Bioorganic Chemistry, University of Graz, NAWI Graz, BioTechMed-Graz, Heinrichstraße 28, A-8010 Graz, Austria
| | - Ruth Prassl
- Institute of Biophysics, Medical University of Graz, BioTechMed-Graz, Harrachgasse 21, A-8010 Graz, Austria
| | - Joachim Reidl
- Institute of Molecular Biosciences, University of Graz, NAWI Graz, BioTechMed-Graz, Humboldtstraße 50, A-8010 Graz, Austria
| | - Günther Daum
- Institute of Biochemistry, Graz University of Technology, NAWI Graz, BioTechMed-Graz, Petersgasse 12/2, A-8010 Graz, Austria
| | - Mario F Feldman
- Alberta Glycomics Centre, Department of Biological Sciences, University of Alberta, CW405 Biological Sciences Building, Edmonton, AB, Canada T6G 2E9
| | - Stefan Schild
- Institute of Molecular Biosciences, University of Graz, NAWI Graz, BioTechMed-Graz, Humboldtstraße 50, A-8010 Graz, Austria.
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Abstract
Otitis media is a major cause of morbidity in 80% of all children less than 3 years of age and often goes undiagnosed in the general population. There is evidence to suggest that the incidence of otitis media is increasing. The major cause of otitis media is infection of the middle ear with microbes from the nasopharynx. The anatomical orientation of the eustachian tube, in association with a number of risk factors, predisposes infants and young children to the infection. Bacteria are responsible for approximately 70% of cases of acute otitis media, with Streptococcus pneumoniae, nontypeable Haemophilus influenzae and Moraxella catarrhalis predominating as the causative agents. The respiratory viruses, respiratory syncytial virus, rhinovirus, parainfluenza and influenza, account for 30% of acute otitis media cases. Over the past decade, there has been a profound increase in the reported resistance to antibiotics, which, with increased disease burden, has focussed attention on vaccine development for otitis media. A polymicrobial formulation containing antigens from all major pathogens would have the greatest potential to deliver a sustained reduction in the disease burden globally. The disappointing outcomes for otitis media seen with the polysaccharide pneumococcal conjugate vaccine have raised major challenges for the vaccination strategy. Clearly, more knowledge is required concerning immune mechanisms in the middle ear, as well as vaccine formulations containing antigens that are more representative of the polymicrobial nature of the disease. Antigens that have been extensively tested in animal models are now available for testing in human subjects.
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Affiliation(s)
- Allan W Cripps
- Griffith University, School of Medicine, Gold Coast Campus, PMB 50, Gold Coast, MC, QLD, 9726, Australia.
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Jaiswal V, Chanumolu SK, Gupta A, Chauhan RS, Rout C. Jenner-predict server: prediction of protein vaccine candidates (PVCs) in bacteria based on host-pathogen interactions. BMC Bioinformatics 2013; 14:211. [PMID: 23815072 PMCID: PMC3701604 DOI: 10.1186/1471-2105-14-211] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Accepted: 06/20/2013] [Indexed: 11/24/2022] Open
Abstract
Background Subunit vaccines based on recombinant proteins have been effective in preventing infectious diseases and are expected to meet the demands of future vaccine development. Computational approach, especially reverse vaccinology (RV) method has enormous potential for identification of protein vaccine candidates (PVCs) from a proteome. The existing protective antigen prediction software and web servers have low prediction accuracy leading to limited applications for vaccine development. Besides machine learning techniques, those software and web servers have considered only protein’s adhesin-likeliness as criterion for identification of PVCs. Several non-adhesin functional classes of proteins involved in host-pathogen interactions and pathogenesis are known to provide protection against bacterial infections. Therefore, knowledge of bacterial pathogenesis has potential to identify PVCs. Results A web server, Jenner-Predict, has been developed for prediction of PVCs from proteomes of bacterial pathogens. The web server targets host-pathogen interactions and pathogenesis by considering known functional domains from protein classes such as adhesin, virulence, invasin, porin, flagellin, colonization, toxin, choline-binding, penicillin-binding, transferring-binding, fibronectin-binding and solute-binding. It predicts non-cytosolic proteins containing above domains as PVCs. It also provides vaccine potential of PVCs in terms of their possible immunogenicity by comparing with experimentally known IEDB epitopes, absence of autoimmunity and conservation in different strains. Predicted PVCs are prioritized so that only few prospective PVCs could be validated experimentally. The performance of web server was evaluated against known protective antigens from diverse classes of bacteria reported in Protegen database and datasets used for VaxiJen server development. The web server efficiently predicted known vaccine candidates reported from Streptococcus pneumoniae and Escherichia coli proteomes. The Jenner-Predict server outperformed NERVE, Vaxign and VaxiJen methods. It has sensitivity of 0.774 and 0.711 for Protegen and VaxiJen dataset, respectively while specificity of 0.940 has been obtained for the latter dataset. Conclusions Better prediction accuracy of Jenner-Predict web server signifies that domains involved in host-pathogen interactions and pathogenesis are better criteria for prediction of PVCs. The web server has successfully predicted maximum known PVCs belonging to different functional classes. Jenner-Predict server is freely accessible at http://117.211.115.67/vaccine/home.html
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Affiliation(s)
- Varun Jaiswal
- Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology, Waknaghat, Solan, Himachal Pradesh 173234, India
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Supanji, Shimomachi M, Hasan MZ, Kawaichi M, Oka C. HtrA1 is induced by oxidative stress and enhances cell senescence through p38 MAPK pathway. Exp Eye Res 2013; 112:79-92. [PMID: 23623979 DOI: 10.1016/j.exer.2013.04.013] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 03/28/2013] [Accepted: 04/15/2013] [Indexed: 01/10/2023]
Abstract
Genetic predisposition and senescence of retinal pigment epithelium induced by oxidative stress are major contributors to age-related macular degeneration (AMD). Single-nucleotide polymorphisms in HTRA1 are strongly linked to the onset of AMD. In this study, we examine the role of HtrA1 in premature senescence and cell death induced by oxidative stress. HtrA1 mRNA and protein were up-regulated during premature senescence induced by H2O2 in both mouse embryonic fibroblasts (MEFs) and ARPE-19 cells. Expression of the senescence markers p21(CIP1/WAF1) and p16(INK4a), and SA-β-galactosidase activity, were higher in HtrA1+/- MEFs than in HtrA1-/- MEFs. HtrA1+/+ and HtrA1+/- MEFs were more resistant than HtrA1-/- MEFs to H2O2-induced cell death. Activation of p38 MAPK by oxidative stress was quicker in HtrA1+/- MEFs than in HtrA1-/- MEFs. The effects of excess HtrA1 were examined by transient transfection of cells with HtrA1 expression vectors or by addition of recombinant proteins. Excess wild type HtrA1 accelerated premature senescence of MEFs and ARPE-19 cells, while the protease-inactive HtrA1 S328A did not. HtrA1-induced senescence was abrogated by inhibition of p38 MAPK. We conclude that HtrA1 is induced by oxidative stress and promotes premature cell senescence through p38 MAPK in a protease activity-dependent manner.
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Affiliation(s)
- Supanji
- Division of Gene Function in Animals, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan
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15
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Coleman JL, Crowley JT, Toledo AM, Benach JL. The HtrA protease of Borrelia burgdorferi degrades outer membrane protein BmpD and chemotaxis phosphatase CheX. Mol Microbiol 2013; 88:619-33. [PMID: 23565798 PMCID: PMC3641820 DOI: 10.1111/mmi.12213] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/20/2013] [Indexed: 12/25/2022]
Abstract
Borrelia burgdorferi, the spirochaetal agent of Lyme disease, codes for a single HtrA protein, HtrABb (BB0104) that is homologous to DegP of Escherichia coli (41% amino acid identity). HtrABb shows physical and biochemical similarities to DegP in that it has the trimer as its fundamental unit and can degrade casein via its catalytic serine. Recombinant HtrABb exhibits proteolytic activity in vitro, while a mutant (HtrABbS198A) does not. However, HtrABb and DegP have some important differences as well. Native HtrABb occurs in both membrane-bound and soluble forms. Despite its homology to DegP, HtrABb could not complement an E. coli DegP deletion mutant. Late stage Lyme disease patients, as well as infected mice and rabbits developed a robust antibody response to HtrABb, indicating that it is a B-cell antigen. In co-immunoprecipitation studies, a number of potential binding partners for HtrABb were identified, as well as two specific proteolytic substrates, basic membrane protein D (BmpD/BB0385) and chemotaxis signal transduction phosphatase CheX (BB0671). HtrABb may function in regulating outer membrane lipoproteins and in modulating the chemotactic response of B. burgdorferi.
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Affiliation(s)
- James L Coleman
- New York State Department of Health, Stony Brook University, Stony Brook, NY 11794-5120, USA.
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16
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Kariu T, Yang X, Marks CB, Zhang X, Pal U. Proteolysis of BB0323 results in two polypeptides that impact physiologic and infectious phenotypes in Borrelia burgdorferi. Mol Microbiol 2013; 88:510-22. [PMID: 23489252 DOI: 10.1111/mmi.12202] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/04/2013] [Indexed: 01/12/2023]
Abstract
Borrelia burgdorferi gene product BB0323 is required for cell fission and pathogen persistence in vivo. Here, we show that BB0323, which is conserved among globally prevalent infectious strains, supports normal spirochaete growth and morphology even at early phases of cell division. We demonstrate that native BB0323 undergoes proteolytic processing at the C-terminus, at a site after the first 202 N-terminal amino acids. We further identified a periplasmic BB0323 binding protein in B. burgdorferi, annotated as BB0104, having serine protease activity responsible for the primary cleavage of BB0323 to produce discrete N- and C-terminal polypeptides. These two BB0323 polypeptides interact with each other, and either individually or as a complex, are associated with multiple functions in spirochaete biology and infectivity. While N-terminal BB0323 is adequate to support cell fission, the C-terminal LysM domain is dispensable for this process, despite its ability to bind B. burgdorferi peptidoglycan. However, the LysM domain or the precisely processed BB0323 product is essential for mammalian infection. As BB0323 is a membrane protein crucial for B. burgdorferi survival in vivo, exploring its function may suggest novel ways to interrupt infection while enhancing our understanding of the intricate spirochaete fission process.
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Affiliation(s)
- Toru Kariu
- Department of Veterinary Medicine and Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, MD 20742, USA
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17
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Prymula R, Schuerman L. 10-valent pneumococcal nontypeable Haemophilus influenzae PD conjugate vaccine: Synflorix. Expert Rev Vaccines 2010; 8:1479-500. [PMID: 19863240 DOI: 10.1586/erv.09.113] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The global burden of disease due to Streptococcus pneumoniae remains high. The licensed 7-valent pneumococcal conjugate vaccine (7vCRM, Prevenar/Prevnar) has successfully reduced invasive disease in the USA, but serotype coverage is incomplete and some evidence suggests that serotype replacement has occurred. Recently, a new 10-valent pneumococcal nontypeable Haemophilus influenzae (NTHi) protein D (PD) conjugate vaccine (PHiD-CV, Synflorix) has been licensed in more than 40 countries, including Europe, for the prevention of invasive disease and acute otitis media (AOM) due to pneumococcus in infants and children. PHiD-CV is immunogenic in infants when administered as a three-dose primary vaccination in a range of schedules and has a safety profile comparable to that of 7vCRM. Additional serotypes in PHiD-CV (1, 5 and 7F) increase overall serotype coverage and improve coverage in specific age groups and against specific disease syndromes. The use of the PD carrier, which provided protection against AOM caused by NTHi in a large efficacy trial testing a prototype of the final vaccine formulation, suggests that PHiD-CV will also provide some protection against AOM due to NTHi.
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Affiliation(s)
- Roman Prymula
- Department of Epidemiology, Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czech Republic.
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18
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Hong W, Peng D, Rivera M, Gu XX. Protection against nontypeable Haemophilus influenzae challenges by mucosal vaccination with a detoxified lipooligosaccharide conjugate in two chinchilla models. Microbes Infect 2009; 12:11-8. [PMID: 19782149 DOI: 10.1016/j.micinf.2009.09.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2009] [Revised: 09/09/2009] [Accepted: 09/11/2009] [Indexed: 11/17/2022]
Abstract
Otitis media (OM) can occur following outset of upper respiratory tract infections. Inhibition of bacterial colonization in nasopharynx (NP) by mucosal vaccination may prevent OM by reducing bacterial invasion of the middle ears (MEs). In this study, 80 chinchillas were intranasally (i.n.) immunized with a detoxified lipooligosaccharide (dLOS)-tetanus toxoid conjugate vaccine of nontypeable Haemophilus influenzae (NTHi) mixed with cholera toxin (CT) or CT alone. All vaccinated animals responded with elevated levels of mucosal and serum anti-LOS antibodies. Two weeks after the last immunization, 40 chinchillas were challenged i.n. with NTHi to evaluate NP colonization and ME infection while the rest of the animals were challenged transbullarly (T.B.) to examine the development of OM. Compared to the control group, the vaccination inhibited not only bacterial colonization in NP and transmission to MEs in the i.n. challenge group but also bacterial colonization in NP and transmission to unchallenged ears in the T.B. challenge group. Though no difference was found in the challenged ears of either group right after the T.B. challenge, an early clearance of NTHi from NP and unchallenged ears as well as less severity of OM in the unchallenged ears were observed in vaccinated animals. Current results along with our previous data indicate that mucosal vaccination is capable of inhibiting NTHi NP colonization and preventing OM occurrence in chinchillas; the i.n. challenge model is preferable for testing the mucosal vaccines while the T.B. challenge model is superior for testing the systemic vaccines.
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Affiliation(s)
- Wenzhou Hong
- Vaccine Research Section, National Institute on Deafness and Other Communication Disorders, Rockville, Maryland 20850, USA
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19
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Chitlaru T, Gat O, Grosfeld H, Inbar I, Gozlan Y, Shafferman A. Identification of in vivo-expressed immunogenic proteins by serological proteome analysis of the Bacillus anthracis secretome. Infect Immun 2007; 75:2841-52. [PMID: 17353282 PMCID: PMC1932864 DOI: 10.1128/iai.02029-06] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2006] [Revised: 02/15/2007] [Accepted: 03/04/2007] [Indexed: 01/24/2023] Open
Abstract
In a previous comparative proteomic study of Bacillus anthracis examining the influence of the virulence plasmids and of various growth conditions on the composition of the bacterial secretome, we identified 64 abundantly expressed proteins (T. Chitlaru, O. Gat, Y. Gozlan, N. Ariel, and A. Shafferman, J. Bacteriol. 188:3551-3571, 2006). Using a battery of sera from B. anthracis-infected animals, in the present study we demonstrated that 49 of these proteins are immunogenic. Thirty-eight B. anthracis immunogens are documented in this study for the first time. The relative immunogenicities of the 49 secreted proteins appear to span a >10,000-fold range. The proteins eliciting the highest humoral response in the course of infection include, in addition to the well-established immunogens protective antigen (PA), Sap, and EA1, GroEL (BA0267), AhpC (BA0345), MntA (BA3189), HtrA (BA3660), 2,3-cyclic nucleotide diesterase (BA4346), collagen adhesin (BAS5205), an alanine amidase (BA0898), and an endopeptidase (BA1952), as well as three proteins having unknown functions (BA0796, BA0799, and BA0307). Of these 14 highly potent secreted immunogens, 11 are known to be associated with virulence and pathogenicity in B. anthracis or in other bacterial pathogens. Combining the results reported here with the results of a similar study of the membranal proteome of B. anthracis (T. Chitlaru, N. Ariel, A. Zvi, M. Lion, B. Velan, A. Shafferman, and E. Elhanany, Proteomics 4:677-691, 2004) and the results obtained in a functional genomic search for immunogens (O. Gat, H. Grosfeld, N. Ariel, I. Inbar, G. Zaide, Y. Broder, A. Zvi, T. Chitlaru, Z. Altboum, D. Stein, S. Cohen, and A. Shafferman, Infect. Immun. 74:3987-4001, 2006), we generated a list of 84 in vivo-expressed immunogens for future evaluation for vaccine development, diagnostics, and/or therapeutic intervention. In a preliminary study, the efficacies of eight immunogens following DNA immunization of guinea pigs were compared to the efficacy of a PA DNA vaccine. All eight immunogens induced specific high antibody titers comparable to the titers elicited by PA; however, unlike PA, none of them provided protection against a lethal challenge (50 50% lethal doses) of virulent B. anthracis strain Vollum spores.
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Affiliation(s)
- Theodor Chitlaru
- Israel Institute for Biological Research, P.O. Box 19, Ness-Ziona 74100, Israel
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20
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Winter LE, Barenkamp SJ. Antibodies specific for the high-molecular-weight adhesion proteins of nontypeable Haemophilus influenzae are opsonophagocytic for both homologous and heterologous strains. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2006; 13:1333-42. [PMID: 17021246 PMCID: PMC1694446 DOI: 10.1128/cvi.00221-06] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The HMW1/HMW2-like adhesion proteins of nontypeable Haemophilus influenzae (NTHI) are expressed by 75% of NTHI strains. Antibodies directed against these proteins are opsonophagocytic in vitro and are protective in an animal model of infection. The objective of the present study was to determine the opsonophagocytic activity of high-titer anti-HMW1/HMW2 immune sera against both homologous and heterologous NTHI strains. Chinchillas were immunized with purified HMW1/HMW2-like proteins from five prototype NTHI strains. Serum opsonophagocytic activity was monitored in an assay that uses a human promyelocytic cell line, HL-60, as the source of phagocytic cells. Preimmune sera did not demonstrate opsonophagocytic killing of any strains. In contrast, the immune sera demonstrated killing of the five homologous NTHI strains at titers ranging from 1:320 to 1:640. The immune sera also demonstrated killing of eight heterologous NTHI strains that express HMW1/HMW2-like proteins at titers ranging from 0 to 1:640. Killing of heterologous strains sometimes demonstrated a prozone phenomenon. None of the immune sera killed NTHI strains that did not express HMW1/HMW2-like proteins. Adsorption of immune sera with HMW1/HMW2-like proteins purified from either homologous or heterologous NTHI strains eliminated opsonophagocytic killing of homologous strains in most cases. These data demonstrate that antibodies produced following immunization with the HMW1/HMW2-like proteins are opsonophagocytic for both homologous and heterologous NTHI and strongly suggest that common epitopes recognized by functionally active antibodies exist on the HMW1/HMW2-like proteins of unrelated NTHI strains. The results argue for the continued investigation of the HMW1/HMW2-like proteins as potential vaccine candidates for the prevention of NTHI disease.
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Affiliation(s)
- Linda E Winter
- Department of Pediatrics, St. Louis University School of Medicine, Saint Louis, MO 63104-1095, USA
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21
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Mo E, Peters SE, Willers C, Maskell DJ, Charles IG. Single, double and triple mutants of Salmonella enterica serovar Typhimurium degP (htrA), degQ (hhoA) and degS (hhoB) have diverse phenotypes on exposure to elevated temperature and their growth in vivo is attenuated to different extents. Microb Pathog 2006; 41:174-82. [PMID: 16949246 DOI: 10.1016/j.micpath.2006.07.004] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2006] [Accepted: 07/11/2006] [Indexed: 11/23/2022]
Abstract
DegP (HtrA) is a well-studied protease involved in survival of bacteria under stress conditions in vitro and in vivo. There are two paralogues of DegP in the Salmonella enterica serovar Typhimurium genome, DegQ and DegS. In order to understand more about the biological significance of this gene family, a series of deg-deletion mutants was generated in S. Typhimurium strain SL3261 by allelic replacement. At elevated temperature in vitro, the viability of degP and degS mutants was reduced when compared with the parent strain whereas the viability of a degQ mutant was not significantly affected. The viability of a double degP-degS mutant at elevated temperature was severely decreased when compared with the respective single mutants or, interestingly, with a triple degP-degQ-degS mutant. All the deg deletions were transduced into the mouse-virulent strain SL1344 and the resultant mutants were injected intravenously into BALB/c mice to test virulence. degP and degS single mutants and all combinations of double and triple mutants were attenuated to different degrees, whereas the single degQ mutant was as virulent as the wild-type strain. Thus, within this gene family, degP and degS appear important for survival at elevated temperature and are necessary for full virulence, whereas a single degQ deletion appears to have no clear role in survival and growth at elevated temperature or in mice.
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Affiliation(s)
- Elaine Mo
- Wolfson Institute for Biomedical Research, University College London, Cruciform Building, Gower Street, London WC1E 6BT, UK.
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22
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Gat O, Grosfeld H, Ariel N, Inbar I, Zaide G, Broder Y, Zvi A, Chitlaru T, Altboum Z, Stein D, Cohen S, Shafferman A. Search for Bacillus anthracis potential vaccine candidates by a functional genomic-serologic screen. Infect Immun 2006; 74:3987-4001. [PMID: 16790772 PMCID: PMC1489694 DOI: 10.1128/iai.00174-06] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2006] [Revised: 03/17/2006] [Accepted: 03/30/2006] [Indexed: 12/28/2022] Open
Abstract
Bacillus anthracis proteins that possess antigenic properties and are able to evoke an immune response were identified by a reductive genomic-serologic screen of a set of in silico-preselected open reading frames (ORFs). The screen included in vitro expression of the selected ORFs by coupled transcription and translation of linear PCR-generated DNA fragments, followed by immunoprecipitation with antisera from B. anthracis-infected animals. Of the 197 selected ORFs, 161 were chromosomal and 36 were on plasmids pXO1 and pXO2, and 138 of the 197 ORFs had putative functional annotations (known ORFs) and 59 had no assigned functions (unknown ORFs). A total of 129 of the known ORFs (93%) could be expressed, whereas only 38 (64%) of the unknown ORFs were successfully expressed. All 167 expressed polypeptides were subjected to immunoprecipitation with the anti-B. anthracis antisera, which revealed 52 seroreactive immunogens, only 1 of which was encoded by an unknown ORF. The high percentage of seroreactive ORFs among the functionally annotated ORFs (37%; 51/129) attests to the predictive value of the bioinformatic strategy used for vaccine candidate selection. Furthermore, the experimental findings suggest that surface-anchored proteins and adhesins or transporters, such as cell wall hydrolases, proteins involved in iron acquisition, and amino acid and oligopeptide transporters, have great potential to be immunogenic. Most of the seroreactive ORFs that were tested as DNA vaccines indeed appeared to induce a humoral response in mice. We list more than 30 novel B. anthracis immunoreactive virulence-related proteins which could be useful in diagnosis, pathogenesis studies, and future anthrax vaccine development.
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Affiliation(s)
- Orit Gat
- Israel Institute for Biological Research, P.O. Box 19, Ness Ziona 74100, Israel.
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23
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Rowley G, Spector M, Kormanec J, Roberts M. Pushing the envelope: extracytoplasmic stress responses in bacterial pathogens. Nat Rev Microbiol 2006; 4:383-94. [PMID: 16715050 DOI: 10.1038/nrmicro1394] [Citation(s) in RCA: 250] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Despite being nutrient rich, the tissues and fluids of vertebrates are hostile to microorganisms, and most bacteria that attempt to take advantage of this environment are rapidly eliminated by host defences. Pathogens have evolved various means to promote their survival in host tissues, including stress responses that enable bacteria to sense and adapt to adverse conditions. Many different stress responses have been described, some of which are responsive to one or a small number of cues, whereas others are activated by a broad range of insults. The surface layers of pathogenic bacteria directly interface with the host and can bear the brunt of the attack by the host armoury. Several stress systems that respond to perturbations in the microbial cell outside of the cytoplasm have been described and are known collectively as extracytoplasmic or envelope stress responses (ESRs). Here, we review the role of the ESRs in the pathogenesis of Gram-negative bacterial pathogens.
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Affiliation(s)
- Gary Rowley
- Molecular Bacteriology Group, Institute of Comparative Medicine, Faculty of Veterinary Medicine, University of Glasgow, Bearsden Road, Glasgow G61 1QH, UK
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24
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Chitlaru T, Gat O, Gozlan Y, Ariel N, Shafferman A. Differential proteomic analysis of the Bacillus anthracis secretome: distinct plasmid and chromosome CO2-dependent cross talk mechanisms modulate extracellular proteolytic activities. J Bacteriol 2006; 188:3551-71. [PMID: 16672610 PMCID: PMC1482852 DOI: 10.1128/jb.188.10.3551-3571.2006] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2006] [Accepted: 02/19/2006] [Indexed: 12/17/2022] Open
Abstract
The secretomes of a virulent Bacillus anthracis strain and of avirulent strains (cured of the virulence plasmids pXO1 and pXO2), cultured in rich and minimal media, were studied by a comparative proteomic approach. More than 400 protein spots, representing the products of 64 genes, were identified, and a unique pattern of protein relative abundance with respect to the presence of the virulence plasmids was revealed. In minimal medium under high CO(2) tension, conditions considered to simulate those encountered in the host, the presence of the plasmids leads to enhanced expression of 12 chromosome-carried genes (10 of which could not be detected in the absence of the plasmids) in addition to expression of 5 pXO1-encoded proteins. Furthermore, under these conditions, the presence of the pXO1 and pXO2 plasmids leads to the repression of 14 chromosomal genes. On the other hand, in minimal aerobic medium not supplemented with CO(2), the virulent and avirulent B. anthracis strains manifest very similar protein signatures, and most strikingly, two proteins (the metalloproteases InhA1 and NprB, orthologs of gene products attributed to the Bacillus cereus group PlcR regulon) represent over 90% of the total secretome. Interestingly, of the 64 identified gene products, at least 31 harbor features characteristic of virulence determinants (such as toxins, proteases, nucleotidases, sulfatases, transporters, and detoxification factors), 22 of which are differentially regulated in a plasmid-dependent manner. The nature and the expression patterns of proteins in the various secretomes suggest that distinct CO(2)-responsive chromosome- and plasmid-encoded regulatory factors modulate the secretion of potential novel virulence factors, most of which are associated with extracellular proteolytic activities.
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Affiliation(s)
- Theodor Chitlaru
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness-Ziona
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25
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Alonso S, Willery E, Renauld-Mongénie G, Locht C. Production of nontypeable Haemophilus influenzae HtrA by recombinant Bordetella pertussis with the use of filamentous hemagglutinin as a carrier. Infect Immun 2005; 73:4295-301. [PMID: 15972522 PMCID: PMC1168604 DOI: 10.1128/iai.73.7.4295-4301.2005] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bordetella pertussis, the etiologic agent of whooping cough, is a highly infectious human pathogen capable of inducing mucosal and systemic immune responses upon a single intranasal administration. In an attenuated, pertussis toxin (PTX)-deficient recombinant form, it may therefore constitute an efficient bacterial vector that is particularly well adapted for the delivery of heterologous antigens to the respiratory mucosa. Filamentous hemagglutinin (FHA) has been used as a carrier to present foreign antigens at the bacterial surface, thereby inducing local, systemic, and protective immune responses to these antigens in mice. Both full-length and truncated (Fha44) forms of FHA have been used for antigen presentation. To investigate the effect of the carrier (FHA or Fha44) on antibody responses to passenger antigens, we genetically fused the HtrA protein of nontypeable Haemophilus influenzae to either FHA form. The fha-htrA and Fha44 gene-htrA hybrids were expressed as single copies inserted into the chromosome of PTX-deficient B. pertussis. Both chimeras were secreted into the culture supernatants of the recombinant strains and were recognized by anti-FHA and anti-HtrA antibodies. Intranasal infection with the strain producing the FHA-HtrA hybrid led to significantly higher anti-HtrA and anti-FHA antibody titers than those obtained in mice infected with the Fha44-HtrA-producing strain. Interestingly, the B. pertussis strain producing the Fha44-HtrA chimera colonized the mouse lungs more efficiently than the parental, Fha44-producing strain and gave rise to higher anti-FHA antibody titers than those induced by the parental strain.
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Affiliation(s)
- Sylvie Alonso
- INSERM U629, Institut Pasteur de Lille, 1 rue du Prof. Calmette, F-59019 Lille, France
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26
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Finco O, Bonci A, Agnusdei M, Scarselli M, Petracca R, Norais N, Ferrari G, Garaguso I, Donati M, Sambri V, Cevenini R, Ratti G, Grandi G. Identification of new potential vaccine candidates against Chlamydia pneumoniae by multiple screenings. Vaccine 2005; 23:1178-88. [PMID: 15629361 DOI: 10.1016/j.vaccine.2004.07.045] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2004] [Accepted: 07/26/2004] [Indexed: 10/26/2022]
Abstract
Chlamydia are intracellular bacteria associated to serious human disease. A vaccine has proved difficult to obtain so far, and current opinions agree that multi-antigen combinations may be required to induce optimal protective responses. In order to identify new potential vaccine candidates, we recently screened the Chlamydia pneumoniae (Cpn) genome and described 53 recombinant proteins which elicited antibodies binding to purified Cpn cells. We now report that six proteins in this group can also induce in vitro neutralizing antibodies. Antibody specificity for the corresponding antigens was assessed by immunoblot analysis of 2DE Cpn protein maps. Furthermore, four of the six in vitro neutralizing antigens (Pmp2, Pmp10, OmpH-like and enolase) could inhibit Cpn dissemination in a hamster model. The results show that these Cpn proteins are immunoaccessible in infectious EBs, and recommend further investigation on their value as vaccine components.
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Affiliation(s)
- Oretta Finco
- IRIS Research Centre, Chiron Vaccines, Via Fiorentina, Siena 153100, Italy
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27
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Wonderling LD, Wilkinson BJ, Bayles DO. The htrA (degP) gene of Listeria monocytogenes 10403S is essential for optimal growth under stress conditions. Appl Environ Microbiol 2004; 70:1935-43. [PMID: 15066783 PMCID: PMC383068 DOI: 10.1128/aem.70.4.1935-1943.2004] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2003] [Accepted: 12/20/2003] [Indexed: 11/20/2022] Open
Abstract
This report describes a mutant of Listeria monocytogenes strain 10403S (serotype 1/2a) with a defective response to conditions of high osmolarity, an environment that L. monocytogenes encounters in some ready-to-eat foods. A library of L. monocytogenes clones mutagenized with Tn917 was generated and scored for sensitivity to 4% NaCl in order to identify genes responsible for growth or survival in elevated-NaCl environments. One of the L. monocytogenes Tn917 mutants, designated strain OSM1, was selected, and the gene interrupted by the transposon was sequenced. A BLAST search with the putative translated amino acid sequence indicated that the interrupted gene product was a homolog of htrA (degP), a gene coding for a serine protease identified as a stress response protein in several gram-positive and gram-negative bacteria. An htrA deletion strain, strain LDW1, was constructed, and the salt-sensitive phenotype of this strain was complemented by introduction of a plasmid carrying the wild-type htrA gene, demonstrating that htrA is necessary for optimal growth under conditions of osmotic stress. Additionally, strain LDW1 was tested for its response to temperature and H(2)O(2) stresses. The results of these growth assays indicated that strain LDW1 grew at a lower rate than the wild-type strain at 44 degrees C but at a rate similar to that of the wild-type strain when incubated at 4 degrees C. In addition, strain LDW1 was significantly more sensitive to a 52 degrees C heat shock than the wild-type strain. Strain LDW1 was also defective in its response to H(2)O(2) challenge at 37 degrees C, since 100 or 150 micro g of H(2)O(2) was more inhibitory for the growth of strain LDW1 than for that of the parent strain. The stress response phenotype observed for strain LDW1 is similar to that observed for other HtrA(-) organisms, which suggests that L. monocytogenes HtrA may play a role in degrading misfolded proteins that accumulate under stress conditions.
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Affiliation(s)
- Laura D Wonderling
- Microbial Food Safety Research Unit, Eastern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, Wyndmoor, Pennsylvania 19038, USA
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Winter LE, Barenkamp SJ. Human antibodies specific for the high-molecular-weight adhesion proteins of nontypeable Haemophilus influenzae mediate opsonophagocytic activity. Infect Immun 2004; 71:6884-91. [PMID: 14638776 PMCID: PMC308909 DOI: 10.1128/iai.71.12.6884-6891.2003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The HMW1- and HMW2-like adhesion proteins of nontypeable Haemophilus influenzae are expressed by 75% of these strains, and antibodies directed against these proteins are protective in animal models of infection. The purpose of the present study was to define the functional activity of human antibodies specific for these proteins in an in vitro complement-dependent opsonophagocytic assay. Human promyelocytic cell line HL-60 served as the source of phagocytic cells, and a commercial preparation of intravenous immunoglobulin (IVIG) served as the source of human antibodies. High-molecular-weight (HMW) proteins were purified from four prototype nontypeable H. influenzae strains and used to prepare solid-phase affinity columns. IVIG was adsorbed on each column to remove strain-specific anti-HMW antibodies and to allow recovery of affinity-purified anti-HMW antibody fractions. Unadsorbed IVIG killed each of the prototype strains at titers of 1:80 to 1:320. HMW-adsorbed sera demonstrated fourfold decreases in opsonophagocytic titer against the homologous strains compared to unadsorbed IVIG. Affinity-purified anti-HMW antibody preparations demonstrated opsonophagocytic titers of 1:20 to 1:80 against the respective homologous strains and opsonophagocytic titers as high as 1:80 against heterologous strains. None of the affinity-purified anti-HMW antibody preparations was opsonophagocytic for a representative nontypeable H. influenzae strain that did not express HMW1- or HMW2-like proteins. These data demonstrate that human antibodies specific for the HMW1/HMW2-like adhesion proteins of nontypeable H. influenzae are opsonophagocytic and that such antibodies recognize epitopes shared by the HMW proteins of unrelated nontypeable H. influenzae strains. These results argue for continued investigation of the HMW1/HMW2-like proteins as potential vaccine candidates for prevention of disease due to nontypeable H. influenzae.
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Affiliation(s)
- Linda E Winter
- Department of Pediatrics, St. Louis University School of Medicine, and the Pediatric Research Institute, Cardinal Glennon Children's Hospital, St. Louis, Missouri 63104-1095, USA
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Kyd JM, Cripps AW, Novotny LA, Bakaletz LO. Efficacy of the 26-kilodalton outer membrane protein and two P5 fimbrin-derived immunogens to induce clearance of nontypeable Haemophilus influenzae from the rat middle ear and lungs as well as from the chinchilla middle ear and nasopharynx. Infect Immun 2003; 71:4691-9. [PMID: 12874350 PMCID: PMC165997 DOI: 10.1128/iai.71.8.4691-4699.2003] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The rat middle ear and lung clearance model has been used to show that the nontypeable Haemophilus influenzae 26-kDa outer membrane protein OMP26 is highly efficacious as a mucosal immunogen, inducing significantly enhanced clearance in immunized rats upon direct challenge of these two anatomic sites. Similarly, the chinchilla model of middle ear and nasopharyngeal clearance has been used to show that two P5 fimbrin adhesin-derived immunogens, LB1 and lipoprotein D (LPD)-LB1(f)(2,1,3), are highly efficacious as parenteral immunogens. Both induced significantly augmented clearance of nontypeable H. influenzae upon challenge of these sites. Here, these three nontypeable H. influenzae immunogens in addition to six bovine serum albumin and keyhole limpet hemocyanin conjugates of the synthetic peptide LB1(f) were assayed for relative efficacy in the reciprocal rodent model system. OMP26 was assayed in the chinchilla host by a parenteral immunization route, with clearance of the middle ear and nasopharynx used as outcome measures. Both LB1 and LPD-LB1(f)(2,1,3) were assayed in the rat host with a mucosal immunization route and clearance of nontypeable H. influenzae from the lungs and middle ears as outcome measures. Both of the immunogens were found to induce a high-titered and specific immune responses in the heterologous host system. Moreover, each was found to be highly efficacious in the reciprocal host system, providing strong support for the continued development and inclusion of both OMP26 and P5 fimbrin-derived peptides as candidate vaccine antigens directed at otitis media caused by nontypeable H. influenzae.
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Affiliation(s)
- Jennelle M Kyd
- Division of Science and Design, Gadi Research Centre, University of Canberra, Canberra, Australia.
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Foucaud-Scheunemann C, Poquet I. HtrA is a key factor in the response to specific stress conditions in Lactococcus lactis. FEMS Microbiol Lett 2003; 224:53-9. [PMID: 12855167 DOI: 10.1016/s0378-1097(03)00419-1] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We investigated the physiological role of Lactococcus lactis housekeeping surface protease HtrA. It is involved in surface properties under regular growth conditions, as the htrA mutant strain forms longer chains in liquid medium. It participates in cellular defence against environmental stress conditions: compared to the wild-type strain, the htrA mutant strain exhibited increased sensitivity to heat, ethanol, puromycin, and NaCl, but not to pH, H2O2, bile salts or to carbon or nitrogen starvation. htrA transcription in the wild-type strain showed a transient increase under stress conditions determined as requiring htrA, but not under overexpression of a secreted heterologous protein. Our results demonstrate that in L. lactis, htrA is a key factor in the response to specific stress conditions.
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Bumann D, Aksu S, Wendland M, Janek K, Zimny-Arndt U, Sabarth N, Meyer TF, Jungblut PR. Proteome analysis of secreted proteins of the gastric pathogen Helicobacter pylori. Infect Immun 2002; 70:3396-403. [PMID: 12065478 PMCID: PMC128097 DOI: 10.1128/iai.70.7.3396-3403.2002] [Citation(s) in RCA: 160] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Secreted proteins (the secretome) of the human pathogen Helicobacter pylori may mediate important pathogen-host interactions, but such proteins are technically difficult to analyze. Here, we report on a comprehensive secretome analysis that uses protein-free culture conditions to minimize autolysis, an efficient recovery method for extracellular proteins, and two-dimensional gel electrophoresis followed by peptide mass fingerprinting for protein resolution and identification. Twenty-six of the 33 separated secreted proteins were identified. Among them were six putative oxidoreductases that may be involved in the modification of protein-disulfide bonds, three flagellar proteins, three defined fragments of the vacuolating toxin VacA, the serine protease HtrA, and eight proteins of unknown function. A cleavage site for the amino-terminal passenger domain of VacA between amino acids 991 and 992 was determined by collision-induced dissociation mass spectrometry. Several of the secreted proteins are interesting targets for antimicrobial chemotherapy and vaccine development.
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Affiliation(s)
- Dirk Bumann
- Department of Molecular Biology, Max-Planck-Institute for Infection Biology, Berlin, Germany
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Alper CM, Andalibi A, Bakaletz LO, Buchman C, Cayé-Thomasen P, Hellstrom SOM, Herman P, Hermansson A, Hussl B, Iino Y, Kawauchi H, Paparella MM, Sando I, Swarts JD, Takasaka T. Recent advances in otitis media. 4. Anatomy, cell biology, pathology, and animal models. Ann Otol Rhinol Laryngol 2002; 188:36-51. [PMID: 11968860 DOI: 10.1177/00034894021110s307] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Montigiani S, Falugi F, Scarselli M, Finco O, Petracca R, Galli G, Mariani M, Manetti R, Agnusdei M, Cevenini R, Donati M, Nogarotto R, Norais N, Garaguso I, Nuti S, Saletti G, Rosa D, Ratti G, Grandi G. Genomic approach for analysis of surface proteins in Chlamydia pneumoniae. Infect Immun 2002; 70:368-79. [PMID: 11748203 PMCID: PMC127649 DOI: 10.1128/iai.70.1.368-379.2002] [Citation(s) in RCA: 147] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Chlamydia pneumoniae, a human pathogen causing respiratory infections and probably contributing to the development of atherosclerosis and heart disease, is an obligate intracellular parasite which for replication needs to productively interact with and enter human cells. Because of the intrinsic difficulty in working with C. pneumoniae and in the absence of reliable tools for its genetic manipulation, the molecular definition of the chlamydial cell surface is still limited, thus leaving the mechanisms of chlamydial entry largely unknown. In an effort to define the surface protein organization of C. pneumoniae, we have adopted a combined genomic-proteomic approach based on (i) in silico prediction from the available genome sequences of peripherally located proteins, (ii) heterologous expression and purification of selected proteins, (iii) production of mouse immune sera against the recombinant proteins to be used in Western blotting and fluorescence-activated cell sorter (FACS) analyses for the identification of surface antigens, and (iv) mass spectrometry analysis of two-dimensional electrophoresis (2DE) maps of chlamydial protein extracts to confirm the presence of the FACS-positive antigens in the chlamydial cell. Of the 53 FACS-positive sera, 41 recognized a protein species with the expected size on Western blots, and 28 of the 53 antigens shown to be surface-exposed by FACS were identified on 2DE maps of elementary-body extracts. This work represents the first systematic attempt to define surface protein organization in C. pneumoniae.
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Affiliation(s)
- Silvia Montigiani
- Chiron SpA, 53100 Siena. Sezione di Microbiologia DMCSS, University of Bologna, 40138 Bologna, Italy
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Sethi S, Murphy TF. Bacterial infection in chronic obstructive pulmonary disease in 2000: a state-of-the-art review. Clin Microbiol Rev 2001; 14:336-63. [PMID: 11292642 PMCID: PMC88978 DOI: 10.1128/cmr.14.2.336-363.2001] [Citation(s) in RCA: 389] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death in the United States. The precise role of bacterial infection in the course and pathogenesis of COPD has been a source of controversy for decades. Chronic bacterial colonization of the lower airways contributes to airway inflammation; more research is needed to test the hypothesis that this bacterial colonization accelerates the progressive decline in lung function seen in COPD (the vicious circle hypothesis). The course of COPD is characterized by intermittent exacerbations of the disease. Studies of samples obtained by bronchoscopy with the protected specimen brush, analysis of the human immune response with appropriate immunoassays, and antibiotic trials reveal that approximately half of exacerbations are caused by bacteria. Nontypeable Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pneumoniae are the most common causes of exacerbations, while Chlamydia pneumoniae causes a small proportion. The role of Haemophilus parainfluenzae and gram-negative bacilli remains to be established. Recent progress in studies of the molecular mechanisms of pathogenesis of infection in the human respiratory tract and in vaccine development guided by such studies promises to lead to novel ways to treat and prevent bacterial infections in COPD.
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Affiliation(s)
- S Sethi
- Division of Pulmonary and Critical Medicine, State University of New York at Buffalo, Buffalo, New York, USA
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Abstract
We screened a phage library of Rickettsia typhi with a polyclonal antiserum to clone genes which encode immunogenic proteins of R. typhi. Among several clones obtained, one clone codes for a 466-amino-acid protein similar to the heat-shock protein, HtrA. The deduced rickettsial HtrA contains a putative signal peptide sequence at the N-terminus, a serine protease-like domain, and two PDZ domains. The recombinant protein of rickettsial HtrA reacted with sera from patients with murine typhus and tsutsugamushi disease. We suggest that this gene and its recombinant protein would be valuable for the immunologic diagnosis of rickettsial diseases.
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Affiliation(s)
- J H Kim
- Department of Microbiology, College of Medicine, Kon-Kuk University, Choongju, South Korea
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Stathopoulos C, Hendrixson DR, Thanassi DG, Hultgren SJ, St Geme JW, Curtiss R. Secretion of virulence determinants by the general secretory pathway in gram-negative pathogens: an evolving story. Microbes Infect 2000; 2:1061-72. [PMID: 10967286 DOI: 10.1016/s1286-4579(00)01260-0] [Citation(s) in RCA: 114] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Secretion of proteins by the general secretory pathway (GSP) is a two-step process requiring the Sec translocase in the inner membrane and a separate substrate-specific secretion apparatus for translocation across the outer membrane. Gram-negative bacteria with pathogenic potential use the GSP to deliver virulence factors into the extracellular environment for interaction with the host. Well-studied examples of virulence determinants using the GSP for secretion include extracellular toxins, pili, curli, autotransporters, and crystaline S-layers. This article reviews our current understanding of the GSP and discusses examples of terminal branches of the GSP which are utilized by factors implicated in bacterial virulence.
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Affiliation(s)
- C Stathopoulos
- Department of Biology, Washington University, One Brookings Drive, St. Louis, MO 63110, USA
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Bakaletz LO, Kennedy BJ, Novotny LA, Duquesne G, Cohen J, Lobet Y. Protection against development of otitis media induced by nontypeable Haemophilus influenzae by both active and passive immunization in a chinchilla model of virus-bacterium superinfection. Infect Immun 1999; 67:2746-62. [PMID: 10338477 PMCID: PMC96578 DOI: 10.1128/iai.67.6.2746-2762.1999] [Citation(s) in RCA: 95] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Three separate studies, two involving active-immunization regimens and one involving a passive-transfer protocol, were conducted to initially screen and ultimately more fully assess several nontypeable Haemophilus influenzae outer membrane proteins or their derivatives for their relative protective efficacy in chinchilla models of otitis media. Initial screening of these antigens (P5-fimbrin, lipoprotein D, and P6), delivered singly or in combination with either Freund's adjuvant or alum, indicated that augmented bacterial clearance from the nasopharynx, the middle ears, or both anatomical sites could be induced by parenteral immunization with P5-fimbrin combined with lipoprotein D, lipoprotein D alone, or the synthetic chimeric peptide LB1 (derived from P5-fimbrin), respectively. Data from a second study, wherein chinchillas were immunized with LB1 or lipoprotein D, each delivered with alum, again indicated that clearance of nontypeable H. influenzae could be augmented by immunization with either of these immunogens; however, when this adjuvant was used, both antibody titers in serum and efficacy were reduced. A third study was performed to investigate passive delivery of antisera directed against either LB1, lipoprotein D, nonacylated lipoprotein D, or a unique recombinant peptide designated LPD-LB1(f)2,1,3. The last three antiserum pools were generated by using the combined adjuvant of alum plus monophosphoryl lipid A. Passive transfer of sera specific for LB1 or LPD-LB1(f)2,1,3 to adenovirus-compromised chinchillas, prior to intranasal challenge with nontypeable H. influenzae, significantly reduced the severity of signs and incidence of otitis media which developed (P </= 0.001). Collectively, these data indicate the continued merit of further developing LB1 and LPD-LB1(f)2,1,3 as components of vaccines for otitis media.
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Affiliation(s)
- L O Bakaletz
- Division of Otologic Research, Department of Otolaryngology, College of Medicine, The Ohio State University, Columbus, Ohio, USA.
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