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Duke JA, Avci FY. Emerging vaccine strategies against the incessant pneumococcal disease. NPJ Vaccines 2023; 8:122. [PMID: 37591986 PMCID: PMC10435554 DOI: 10.1038/s41541-023-00715-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 08/01/2023] [Indexed: 08/19/2023] Open
Abstract
The incidence of invasive pneumococcal disease (IPD) caused by infection with the pathogen Streptococcus pneumoniae (Spn) has been on a downward trend for decades due to worldwide vaccination programs. Despite the clinical successes observed, the Center for Disease Control (CDC) reports that the continued global burden of S. pneumoniae will be in the millions each year, with a case-fatality rate hovering around 5%. Thus, it is a top priority to continue developing new Spn vaccination strategies to harness immunological insight and increase the magnitude of protection provided. As emphasized by the World Health Organization (WHO), it is also crucial to broaden the implementation of vaccines that are already obtainable in the clinical setting. This review focuses on the immune mechanisms triggered by existing pneumococcal vaccines and provides an overview of the current and upcoming clinical strategies being employed. We highlight the associated challenges of serotype selectivity and using pneumococcal-derived proteins as alternative vaccine antigens.
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Affiliation(s)
- Jeremy A Duke
- Sanofi, Suite 300, 2501 Discovery Drive, Orlando, FL, 32826, USA
| | - Fikri Y Avci
- Department of Biochemistry, Emory Vaccine Center, Emory University School of Medicine, Atlanta, GA, 30322, USA.
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Gaikwad WK, Jana SK, Dhere RM, Ravenscroft N, Kodam KM. Purification of capsular polysaccharides isolated from S. pneumoniae serotype 2 by hydrogen peroxide and endonuclease. Carbohydr Polym 2022; 294:119783. [DOI: 10.1016/j.carbpol.2022.119783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 06/13/2022] [Accepted: 06/22/2022] [Indexed: 11/02/2022]
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A Structural Model for the Ligand Binding of Pneumococcal Serotype 3 Capsular Polysaccharide-Specific Protective Antibodies. mBio 2021; 12:e0080021. [PMID: 34061603 PMCID: PMC8262990 DOI: 10.1128/mbio.00800-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Capsular polysaccharides (CPSs) are major virulence factors that decorate the surfaces of many human bacterial pathogens. In their pure form or as glycoconjugate vaccines, CPSs are extensively used in vaccines deployed in clinical practice worldwide. However, our understanding of the structural requirements for interactions between CPSs and antibodies is limited. A longstanding model based on comprehensive observations of antibody repertoires binding to CPSs is that antibodies expressing heavy chain variable gene family 3 (VH3) predominate in these binding interactions in humans and VH3 homologs in mice. Toward understanding this highly conserved interaction, we generated a panel of mouse monoclonal antibodies (MAb) against Streptococcus pneumoniae serotype 3 CPS, determined an X-ray crystal structure of a protective MAb in complex with a hexasaccharide derived from enzymatic hydrolysis of the polysaccharide, and elucidated the structural requirements for this binding interaction. The crystal structure revealed a binding pocket containing aromatic side chains, suggesting the importance of hydrophobicity in the interaction. Through mutational analysis, we determined the amino acids that are critical in carbohydrate binding. Through elucidating the structural and functional properties of a panel of murine MAbs, we offer an explanation for the predominant use of the human VH3 gene family in antibodies against CPSs with implications in knowledge-based vaccine design.
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Wantuch PL, Jella S, Duke JA, Mousa JJ, Henrissat B, Glushka J, Avci FY. Characterization of the β-glucuronidase Pn3Pase as the founding member of glycoside hydrolase family GH169. Glycobiology 2020; 31:266-274. [PMID: 32810871 DOI: 10.1093/glycob/cwaa070] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 07/20/2020] [Accepted: 07/21/2020] [Indexed: 12/25/2022] Open
Abstract
Paenibacillus sp. 32352 is a soil-dwelling bacterium capable of producing an enzyme, Pn3Pase that degrades the capsular polysaccharide of Streptococcus pneumoniae serotype 3 (Pn3P). Recent reports on Pn3Pase have demonstrated its initial characterization and potential for protection against highly virulent S. pneumoniae serotype 3 infections. Initial experiments revealed this enzyme functions as an exo-β1,4-glucuronidase cleaving the β(1,4) linkage between glucuronic acid and glucose. However, the catalytic mechanism of this enzyme is still unknown. Here, we report the detailed biochemical analysis of Pn3Pase. Pn3Pase shows no significant sequence similarity to known glycoside hydrolase (GH) families, thus this novel enzyme establishes a new carbohydrate-active enzyme (CAZy) GH family. Site-directed mutagenesis studies revealed two catalytic residues along with truncation mutants defining essential domains for function. Pn3Pase and its mutants were screened for activity, substrate binding and kinetics. Additionally, nuclear magnetic resonance spectroscopy analysis revealed that Pn3Pase acts through a retaining mechanism. This study exhibits Pn3Pase activity at the structural and mechanistic level to establish the new CAZy GH family GH169 belonging to the large GH-A clan. This study will also serve toward generating Pn3Pase derivatives with optimal activity and pharmacokinetics aiding in the use of Pn3Pase as a novel therapeutic approach against type 3 S. pneumoniae infections.
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Affiliation(s)
- Paeton L Wantuch
- Department of Biochemistry & Molecular Biology, University of Georgia, 325 Riverbend Rd, Athens GA 30602, USA.,Center for Molecular Medicine, University of Georgia, 325 Riverbend Rd, Athens GA 30602, USA
| | - Satya Jella
- Center for Molecular Medicine, University of Georgia, 325 Riverbend Rd, Athens GA 30602, USA
| | - Jeremy A Duke
- Department of Biochemistry & Molecular Biology, University of Georgia, 325 Riverbend Rd, Athens GA 30602, USA.,Center for Molecular Medicine, University of Georgia, 325 Riverbend Rd, Athens GA 30602, USA
| | - Jarrod J Mousa
- Center for Vaccines and Immunology, College of Veterinary Medicine, University of Georgia, 501 D.W. Brooks Dr Athens, Athens GA 30602, USA.,Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, 501 D.W. Brooks Dr Athens, Athens GA 30602, USA
| | - Bernard Henrissat
- Architecture et Fonction des Macromolécules Biologiques, CNRS, Aix-Marseille University, 163 Avenue de Luminy, Parc Scientifique et Technologique de Luminy, 13288 Marseille, France.,USC1408 Architecture et Fonction des Macromolécules Biologiques, Institut National de la Recherche Agronomique, 163 Avenue de Luminy, Parc Scientifique et Technologique de Luminy, 13288 Marseille, France.,Department of Biological Sciences, King Abdulaziz University, Al Jami`ah, Jeddah, 23218, Saudi Arabia
| | - John Glushka
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Rd, Athens GA 30602, USA
| | - Fikri Y Avci
- Department of Biochemistry & Molecular Biology, University of Georgia, 325 Riverbend Rd, Athens GA 30602, USA.,Center for Molecular Medicine, University of Georgia, 325 Riverbend Rd, Athens GA 30602, USA
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Cheng S, Wantuch PL, Kizer ME, Middleton DR, Wang R, DiBello M, Li M, Wang X, Li X, Ramachandiran V, Avci FY, Zhang F, Zhang X, Linhardt RJ. Glycoconjugate synthesis using chemoselective ligation. Org Biomol Chem 2020; 17:2646-2650. [PMID: 30778481 DOI: 10.1039/c9ob00270g] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Chemoselective ligation of carbohydrates and polypeptides was achieved using an adipic acid dihydrazide cross-linker. The reducing end of a carbohydrate is efficiently attached to peptides in two steps, constructing a glycoconjugate in high yield and with high regioselectivity, enabling the production of homogeneous glycoconjugates.
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Affiliation(s)
- Shuihong Cheng
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, Chaoyang, China
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Xu Y, Mao W, Gao W, Chi Z, Chi Z, Liu G. Efficient production of a recombinant ι-carrageenase in Brevibacillus choshinensis using a new integrative vector for the preparation of ι-carrageenan oligosaccharides. Process Biochem 2019. [DOI: 10.1016/j.procbio.2018.09.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Enzymatic Hydrolysis of Pneumococcal Capsular Polysaccharide Renders the Bacterium Vulnerable to Host Defense. Infect Immun 2018; 86:IAI.00316-18. [PMID: 29866907 DOI: 10.1128/iai.00316-18] [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] [Received: 04/26/2018] [Accepted: 05/30/2018] [Indexed: 12/15/2022] Open
Abstract
Despite a century of investigation, Streptococcus pneumoniae remains a major human pathogen, causing a number of diseases, such as pneumonia, meningitis, and otitis media. Like many encapsulated pathogens, the capsular polysaccharide (CPS) of S. pneumoniae is a critical component for colonization and virulence in mammalian hosts. This study aimed to evaluate the protective role of a glycoside hydrolase, Pn3Pase, targeting the CPS of type 3 S. pneumoniae, which is one of the most virulent serotypes. We have assessed the ability of Pn3Pase to degrade the capsule on a live type 3 strain. Through in vitro assays, we observed that Pn3Pase treatment increases the bacterium's susceptibility to phagocytosis by macrophages and complement-mediated killing by neutrophils. We have demonstrated that in vivo Pn3Pase treatment reduces nasopharyngeal colonization and protects mice from sepsis caused by type 3 S. pneumoniae Due to the increasing shifts in serotype distribution, the rise in drug-resistant strains, and poor immune responses to vaccine-included serotypes, it is necessary to investigate approaches to combat pneumococcal infections. This study evaluates the interaction of pneumococcal CPS with the host at molecular, cellular, and systemic levels and offers an alternative therapeutic approach for diseases caused by S. pneumoniae through enzymatic hydrolysis of the CPS.
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Boulos S, Nyström L. Complementary Sample Preparation Strategies for Analysis of Cereal β-Glucan Oxidation Products by UPLC-MS/MS. Front Chem 2017; 5:90. [PMID: 29164106 PMCID: PMC5673685 DOI: 10.3389/fchem.2017.00090] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 10/17/2017] [Indexed: 11/18/2022] Open
Abstract
The oxidation of cereal (1→3,1→4)-β-D-glucan can influence the health promoting and technological properties of this linear, soluble homopolysaccharide by introduction of new functional groups or chain scission. Apart from deliberate oxidative modifications, oxidation of β-glucan can already occur during processing and storage, which is mediated by hydroxyl radicals (HO•) formed by the Fenton reaction. We present four complementary sample preparation strategies to investigate oat and barley β-glucan oxidation products by hydrophilic interaction ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), employing selective enzymatic digestion, graphitized carbon solid phase extraction (SPE), and functional group labeling techniques. The combination of these methods allows for detection of both lytic (C1, C3/4, C5) and non-lytic (C2, C4/3, C6) oxidation products resulting from HO•-attack at different glucose-carbons. By treating oxidized β-glucan with lichenase and β-glucosidase, only oxidized parts of the polymer remained in oligomeric form, which could be separated by SPE from the vast majority of non-oxidized glucose units. This allowed for the detection of oligomers with mid-chain glucuronic acids (C6) and carbonyls, as well as carbonyls at the non-reducing end from lytic C3/C4 oxidation. Neutral reducing ends were detected by reductive amination with anthranilic acid/amide as labeled glucose and cross-ring cleaved units (arabinose, erythrose) after enzyme treatment and SPE. New acidic chain termini were observed by carbodiimide-mediated amidation of carboxylic acids as anilides of gluconic, arabinonic, and erythronic acids. Hence, a full characterization of all types of oxidation products was possible by combining complementary sample preparation strategies. Differences in fine structure depending on source (oat vs. barley) translates to the ratio of observed oxidized oligomers, with in-depth analysis corroborating a random HO•-attack on glucose units irrespective of glycosidic linkage and neighborhood. The method was demonstrated to be (1) sufficiently sensitive to allow for the analysis of oxidation products also from a mild ascorbate-driven Fenton reaction, and (2) to be specific for cereal β-glucan even in the presence of other co-oxidized polysaccharides. This opens doors to applications in food processing to assess potential oxidations and provides the detailed structural basis to understand the effect oxidized functional groups have on β-glucan's health promoting and technological properties.
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Affiliation(s)
| | - Laura Nyström
- Institute of Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland
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Boulos S, Nyström L. UPLC-MS/MS investigation of β-glucan oligosaccharide oxidation. Analyst 2016; 141:6533-6548. [DOI: 10.1039/c6an01125j] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Fenton-induced degradation of isomeric β-d-glucotetraoses is systematically investigated by negative mode HILIC UPLC-MS/MS with regard to the effect of the glycosidic linkage on kinetics, product profiles, and MS/MS fragmentation patterns.
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Affiliation(s)
- Samy Boulos
- ETH Zurich
- Institute of Food
- Nutrition and Health
- 8092 Zurich
- Switzerland
| | - Laura Nyström
- ETH Zurich
- Institute of Food
- Nutrition and Health
- 8092 Zurich
- Switzerland
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