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Mabrook M, Abd El-Aziz AM, Youssif M A, Hassan R. Inhibition of CL-11 reduces pulmonary inflammation in a mouse model of Klebsiella pneumoniae lung infection. Microb Pathog 2022; 164:105408. [PMID: 35063609 DOI: 10.1016/j.micpath.2022.105408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 01/08/2022] [Accepted: 01/13/2022] [Indexed: 11/24/2022]
Abstract
Infection caused by K. pneumoniae is associated with severe inflammation due to stimulation of the innate immune components including the complement system, which is the main player of the innate immune response. Excessive complement-mediated inflammation may cause severe lung injury. Here we clearly show that K. pneumoniae binds to different lectin pathway carbohydrate recognition molecules and activates the complement cascade via the LP. Administration of anti-CL-11 antibodies 6 h before the infection impairs LP functional activity but it shows no effect on the survival time of mice infected with K. pneumoniae. Similarly, no significant difference in bacterial load in blood and lung tissues was observed between mice that received anti-CL-11 and control group treated with an isotype antibody. Interestingly, treatment of mice with anti-CL-11 prior to infection significantly improved histopathological changes and lung injury score induced by K. pneumoniae. Moreover, administration of anti-CL-11 reduced leukocytes infiltration into lung tissues and decreased the levels of the inflammatory mediators TNF-α, IL-6, and IL-1β in the infected mice. These findings indicate that inhibition of the LP could secure a significant level of protection against lung injury during the infection caused by K. pneumoniae.
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Affiliation(s)
- Maha Mabrook
- Department of Microbiology and Immunology, Faculty of Pharmacy, Mansoura University, Mansoura, 35516, Egypt
| | - Abeer M Abd El-Aziz
- Department of Microbiology and Immunology, Faculty of Pharmacy, Mansoura University, Mansoura, 35516, Egypt
| | - Ali Youssif M
- Department of Microbiology and Immunology, Faculty of Pharmacy, Mansoura University, Mansoura, 35516, Egypt; Department of Veterinary Medicine, School of Biological Sciences, University of Cambridge, Cambridge, United Kingdom.
| | - Ramadan Hassan
- Department of Microbiology and Immunology, Faculty of Pharmacy, Mansoura University, Mansoura, 35516, Egypt
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Hagag YA, Said HS, Kenawy HI, Hassan R. A novel pentavalent vaccine candidate completely protects against Acinetobacter baumannii in a mouse model of peritonitis. Appl Microbiol Biotechnol 2022; 106:8151-8167. [PMID: 36401642 PMCID: PMC9676856 DOI: 10.1007/s00253-022-12231-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 09/30/2022] [Accepted: 10/05/2022] [Indexed: 11/21/2022]
Abstract
Acinetobacter baumannii is considered as one of the most virulent and infectious organisms that have an increased ability to both evade host immune response and resist various classes of antibiotics, leading to life-threatening infections. Multiple virulence factors have been implicated in the high prevalence rate of A. baumannii in hospitalized and immunocompromised patients. Moreover, improper use of antibiotics has led to the emergence of extensive drug-resistant strains that urgently require alternative strategies to control this superbug. Unfortunately, the availability of a licensed vaccine against A. baumannii infections is still challenged by the vast diversity among A. baumannii strains. Here, we report the development of a novel pentavalent vaccine candidate composed of two recombinant proteins (Wza and YiaD) and a pool of capsular polysaccharides isolated from 3 clinical isolates. We tested this new vaccine in vivo in a mouse model of peritonitis against the standard strain ATCC 19606 in addition to 3 clinical isolates of A. baumannii. Immunization with this vaccine completely protected the challenged mice with 100% survival rate in the case of all the tested bacteria. Further clinical studies are urgently needed to evaluate the efficacy and safety of this proprietary vaccine to protect patients from A. baumannii lethal infections. KEY POINTS: • Recombinant proteins pool (Wza and YiaD) immunization led to a synergistic immune response. • Capsular polysaccharides pool induced up to 90% protection of tested clinical isolates. • The pentavalent pool showed superiority with 100% survival of immunized mice.
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Affiliation(s)
- Yomna A. Hagag
- Department of Microbiology and Immunology, Faculty of Pharmacy, Mansoura University, Mansoura, 35516 Egypt
| | - Heba Shehta Said
- Department of Microbiology and Immunology, Faculty of Pharmacy, Mansoura University, Mansoura, 35516 Egypt
| | - Hany I. Kenawy
- Department of Microbiology and Immunology, Faculty of Pharmacy, Mansoura University, Mansoura, 35516 Egypt
| | - Ramadan Hassan
- Department of Microbiology and Immunology, Faculty of Pharmacy, Mansoura University, Mansoura, 35516 Egypt
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Inhibition of the Classical Pathway of Complement Activation Impairs Bacterial Clearance during Enterococcus faecalis Infection. Infect Immun 2021; 89:IAI.00660-20. [PMID: 33593889 DOI: 10.1128/iai.00660-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Accepted: 01/07/2021] [Indexed: 12/18/2022] Open
Abstract
Enterococcus faecalis infections are considered a major public health concern worldwide. The complement system has a crucial role in the protection against different microbial pathogens, including E. faecalis Complement can be activated through three different pathways, including the classical, lectin, and alternative pathways. There is limited information on the role of the classical pathway (CP) in protection against infections caused by E. faecalis In the present study, we generated Fab fragments that successfully block the CP in mouse via inhibition of a key enzyme, C1s-A. Our results showed that anti-C1s-A Fab fragments block CP-mediated C3b and C4b deposition in vitro We further showed that administration of anti-C1s-A Fab fragments significantly impairs the CP functional activity in vivo Moreover, treatment of mice infected with E. faecalis using anti-C1s-A Fab fragments significantly impairs bacterial clearance as determined from the viable bacterial counts recovered from blood, kidneys, spleens, livers, and lungs of infected mice. Overall, this study highlights the essential role of the CP in host defense against E. faecalis.
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Du S, Vilhena C, King S, Sahagún-Ruiz A, Hammerschmidt S, Skerka C, Zipfel PF. Molecular analyses identifies new domains and structural differences among Streptococcus pneumoniae immune evasion proteins PspC and Hic. Sci Rep 2021; 11:1701. [PMID: 33462258 PMCID: PMC7814132 DOI: 10.1038/s41598-020-79362-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 12/07/2020] [Indexed: 12/13/2022] Open
Abstract
The PspC and Hic proteins of Streptococcuspneumoniae are some of the most variable microbial immune evasion proteins identified to date. Due to structural similarities and conserved binding profiles, it was assumed for a long time that these pneumococcal surface proteins represent a protein family comprised of eleven subgroups. Recently, however, the evaluation of more proteins revealed a greater diversity of individual proteins. In contrast to previous assumptions a pattern evaluation of six PspC and five Hic variants, each representing one of the previously defined subgroups, revealed distinct structural and likely functionally regions of the proteins, and identified nine new domains and new domain alternates. Several domains are unique to PspC and Hic variants, while other domains are also present in other virulence factors encoded by pneumococci and other bacterial pathogens. This knowledge improved pattern evaluation at the level of full-length proteins, allowed a sequence comparison at the domain level and identified domains with a modular composition. This novel strategy increased understanding of individual proteins variability and modular domain composition, enabled a structural and functional characterization at the domain level and furthermore revealed substantial structural differences between PspC and Hic proteins. Given the exceptional genomic diversity of the multifunctional PspC and Hic proteins a detailed structural and functional evaluation need to be performed at the strain level. Such knowledge will also be useful for molecular strain typing and characterizing PspC and Hic proteins from new clinical S. pneumoniae strains.
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Affiliation(s)
- Shanshan Du
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Cláudia Vilhena
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Samantha King
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, USA.,Department of Pediatrics, The Ohio State University, Columbus, OH, USA
| | - Alfredo Sahagún-Ruiz
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany.,Molecular Immunology Laboratory, Department of Microbiology and Immunology, Faculty of Veterinary Medicine and Animal Husbandry, National Autonomous University of Mexico, Mexico City, Mexico
| | - Sven Hammerschmidt
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald, Germany
| | - Christine Skerka
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Peter F Zipfel
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany. .,Institute of Microbiology, Friedrich-Schiller-University, Jena, Germany.
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