1
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Kelly SD, Duong NH, Nothof JT, Lowary TL, Whitfield C. Three-component systems represent a common pathway for extracytoplasmic addition of pentofuranose sugars into bacterial glycans. Proc Natl Acad Sci U S A 2024; 121:e2402554121. [PMID: 38748580 PMCID: PMC11127046 DOI: 10.1073/pnas.2402554121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Accepted: 04/18/2024] [Indexed: 05/27/2024] Open
Abstract
Cell surface glycans are major drivers of antigenic diversity in bacteria. The biochemistry and molecular biology underpinning their synthesis are important in understanding host-pathogen interactions and for vaccine development with emerging chemoenzymatic and glycoengineering approaches. Structural diversity in glycostructures arises from the action of glycosyltransferases (GTs) that use an immense catalog of activated sugar donors to build the repeating unit and modifying enzymes that add further heterogeneity. Classical Leloir GTs incorporate α- or β-linked sugars by inverting or retaining mechanisms, depending on the nucleotide sugar donor. In contrast, the mechanism of known ribofuranosyltransferases is confined to β-linkages, so the existence of α-linked ribofuranose in some glycans dictates an alternative strategy. Here, we use Citrobacter youngae O1 and O2 lipopolysaccharide O antigens as prototypes to describe a widespread, versatile pathway for incorporating side-chain α-linked pentofuranoses by extracytoplasmic postpolymerization glycosylation. The pathway requires a polyprenyl phosphoribose synthase to generate a lipid-linked donor, a MATE-family flippase to transport the donor to the periplasm, and a GT-C type GT (founding the GT136 family) that performs the final glycosylation reaction. The characterized system shares similarities, but also fundamental differences, with both cell wall arabinan biosynthesis in mycobacteria, and periplasmic glucosylation of O antigens first discovered in Salmonella and Shigella. The participation of auxiliary epimerases allows the diversification of incorporated pentofuranoses. The results offer insight into a broad concept in microbial glycobiology and provide prototype systems and bioinformatic guides that facilitate discovery of further examples from diverse species, some in currently unknown glycans.
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Affiliation(s)
- Steven D. Kelly
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ONN1G 2W1, Canada
| | - Nam Ha Duong
- Institute of Biological Chemistry, Academia Sinica, Nangang, Taipei11529, Taiwan
- Chemical Biology and Molecular Biophysics, Taiwan International Graduate Program, Academia Sinica, Nangang, Taipei11529, Taiwan
- Department of Chemistry, National Tsing Hua University, Hsinchu300044, Taiwan
| | - Jeremy T. Nothof
- Department of Chemistry, University of Alberta, Edmonton, ABT6G 2G2, Canada
| | - Todd L. Lowary
- Institute of Biological Chemistry, Academia Sinica, Nangang, Taipei11529, Taiwan
- Department of Chemistry, University of Alberta, Edmonton, ABT6G 2G2, Canada
- Institute of Biochemical Sciences, National Taiwan University, Taipei10617, Taiwan
| | - Chris Whitfield
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ONN1G 2W1, Canada
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2
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Palčeková Z, De K, Angala SK, Gilleron M, Zuberogoitia S, Gouxette L, Soto-Ojeda M, Gonzalez-Juarrero M, Obregón-Henao A, Nigou J, Wheat WH, Jackson M. Impact of Methylthioxylose Substituents on the Biological Activities of Lipomannan and Lipoarabinomannan in Mycobacterium tuberculosis. ACS Infect Dis 2024; 10:1379-1390. [PMID: 38511206 PMCID: PMC11014759 DOI: 10.1021/acsinfecdis.4c00079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/22/2024]
Abstract
Two lipoglycans, lipomannan (LM) and lipoarabinomannan (LAM), play various, albeit incompletely defined, roles in the interactions of mycobacteria with the host. Growing evidence points to the modification of LM and LAM with discrete covalent substituents as a strategy used by these bacteria to modulate their biological activities. One such substituent, originally identified in Mycobacterium tuberculosis (Mtb), is a 5-methylthio-d-xylose (MTX) sugar, which accounts for the antioxidative properties of LAM. The widespread distribution of this motif across Mtb isolates from several epidemiologically important lineages have stimulated interest in MTX-modified LAM as a biomarker of tuberculosis infection. Yet, several lines of evidence indicate that MTX may not be restricted to Mtb and that this motif may substitute more acceptors than originally thought. Using a highly specific monoclonal antibody to the MTX capping motif of Mtb LAM, we here show that MTX motifs not only substitute the mannoside caps of LAM but also the mannan core of LM in Mtb. MTX substituents were also found on the LM and LAM of pathogenic, slow-growing nontuberculous mycobacteria. The presence of MTX substituents on the LM and LAM from Mtb enhances the pro-apoptotic properties of both lipoglycans on LPS-stimulated THP-1 macrophages. A comparison of the cytokines and chemokines produced by resting and LPS-activated THP-1 cells upon exposure to MTX-proficient versus MTX-deficient LM further indicates that MTX substituents confer anti-inflammatory properties upon LM. These findings add to our understanding of the glycan-based strategies employed by slow-growing pathogenic mycobacteria to alter the host immune response to infection.
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Affiliation(s)
- Zuzana Palčeková
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1682, USA
| | - Kavita De
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1682, USA
| | - Shiva Kumar Angala
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1682, USA
| | - Martine Gilleron
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, 31077 Toulouse, France
| | - Sophie Zuberogoitia
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, 31077 Toulouse, France
| | - Lucie Gouxette
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, 31077 Toulouse, France
| | - Maritza Soto-Ojeda
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1682, USA
| | - Mercedes Gonzalez-Juarrero
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1682, USA
| | - Andrés Obregón-Henao
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1682, USA
| | - Jérôme Nigou
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, 31077 Toulouse, France
| | - William H. Wheat
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1682, USA
| | - Mary Jackson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1682, USA
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3
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Torrelles JB, Chatterjee D. Collected Thoughts on Mycobacterial Lipoarabinomannan, a Cell Envelope Lipoglycan. Pathogens 2023; 12:1281. [PMID: 38003746 PMCID: PMC10675199 DOI: 10.3390/pathogens12111281] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 10/18/2023] [Accepted: 10/24/2023] [Indexed: 11/26/2023] Open
Abstract
The presence of lipoarabinomannan (LAM) in the Mycobacterium tuberculosis (Mtb) cell envelope was first reported close to 100 years ago. Since then, numerous studies have been dedicated to the isolation, purification, structural definition, and elucidation of the biological properties of Mtb LAM. In this review, we present a brief historical perspective on the discovery of Mtb LAM and the herculean efforts devoted to structurally characterizing the molecule because of its unique structural and biological features. The significance of LAM remains high to this date, mainly due to its distinct immunological properties in conjunction with its role as a biomarker for diagnostic tests due to its identification in urine, and thus can serve as a point-of-care diagnostic test for tuberculosis (TB). In recent decades, LAM has been thoroughly studied and massive amounts of information on this intriguing molecule are now available. In this review, we give the readers a historical perspective and an update on the current knowledge of LAM with information on the inherent carbohydrate composition, which is unique due to the often puzzling sugar residues that are specifically found on LAM. We then guide the readers through the complex and myriad immunological outcomes, which are strictly dependent on LAM's chemical structure. Furthermore, we present issues that remain unresolved and represent the immediate future of LAM research. Addressing the chemistry, functions, and roles of LAM will lead to innovative ways to manipulate the processes that involve this controversial and fascinating biomolecule.
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Affiliation(s)
- Jordi B. Torrelles
- International Center for the Advancement of Research and Education (I • Care), Texas Biomedical Research Institute, San Antonio, TX 78227, USA
- Population Health Program, Texas Biomedical Research Institute, San Antonio, TX 78227, USA
| | - Delphi Chatterjee
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA
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4
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Liu Y, Chen T, Zhu Y, Furey A, Lowary TL, Chan J, Bournazos S, Ravetch JV, Achkar JM. Features and protective efficacy of human mAbs targeting Mycobacterium tuberculosis arabinomannan. JCI Insight 2023; 8:e167960. [PMID: 37733444 PMCID: PMC10619501 DOI: 10.1172/jci.insight.167960] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 09/06/2023] [Indexed: 09/23/2023] Open
Abstract
A better understanding of the epitopes most relevant for antibody-mediated protection against tuberculosis (TB) remains a major knowledge gap. We have shown that human polyclonal IgG against the Mycobacterium tuberculosis (M. tuberculosis) surface glycan arabinomannan (AM) and related lipoarabinomannan (LAM) is protective against TB. To investigate the impact of AM epitope recognition and Fcγ receptor (FcγR) binding on antibody functions against M. tuberculosis, we isolated a high-affinity human monoclonal antibody (mAb; P1AM25) against AM and showed its binding to oligosaccharide (OS) motifs we previously found to be associated with in vitro functions of human polyclonal anti-AM IgG. Human IgG1 P1AM25, but not 2 other high-affinity human IgG1 anti-AM mAbs reactive with different AM OS motifs, enhanced M. tuberculosis phagocytosis by macrophages and reduced intracellular growth in an FcγR-dependent manner. P1AM25 in murine IgG2a, but neither murine IgG1 nor a non-FcγR-binding IgG, given intraperitoneally prior to and after aerosolized M. tuberculosis infection, was protective in C57BL/6 mice. Moreover, we demonstrated the protective efficacy of human IgG1 P1AM25 in passive transfer with M. tuberculosis-infected FcγR-humanized mice. These data enhance our knowledge of the important interplay between both antibody epitope specificity and Fc effector functions in the defense against M. tuberculosis and could inform development of vaccines against TB.
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Affiliation(s)
- Yanyan Liu
- Department of Microbiology and Immunology and
| | - Tingting Chen
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Yongqi Zhu
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Aisha Furey
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Todd L. Lowary
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
| | - John Chan
- Public Health Research Institute at the International Center for Public Health, New Jersey Medical School – Rutgers, The State University of New Jersey, Newark, New Jersey, USA
| | | | | | - Jacqueline M. Achkar
- Department of Microbiology and Immunology and
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, USA
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5
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Corrigan DT, Ishida E, Chatterjee D, Lowary TL, Achkar JM. Monoclonal antibodies to lipoarabinomannan/arabinomannan - characteristics and implications for tuberculosis research and diagnostics. Trends Microbiol 2023; 31:22-35. [PMID: 35918247 PMCID: PMC9771891 DOI: 10.1016/j.tim.2022.07.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 07/01/2022] [Accepted: 07/04/2022] [Indexed: 12/24/2022]
Abstract
Antibodies to the mycobacterial surface lipoglycan lipoarabinomannan (LAM) and its related capsular polysaccharide arabinomannan (AM) are increasingly important for investigations focused on both understanding mechanisms of protection against Mycobacterium tuberculosis (Mtb) and developing next-generation point-of-care tuberculosis (TB) diagnostics. We provide here an overview of the growing pipeline of monoclonal antibodies (mAbs) to LAM/AM. Old and new methodologies for their generation are reviewed and we outline and discuss their glycan epitope specificity and other features with implications for the TB field.
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Affiliation(s)
- Devin T Corrigan
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, USA; Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Elise Ishida
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Delphi Chatterjee
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Todd L Lowary
- Institute of Biological Chemistry, Academia Sinica, Nangang Taipei, Taiwan; Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
| | - Jacqueline M Achkar
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, USA; Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA.
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6
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Ashokcoomar S, Reedoy KS, Loots DT, Beukes D, van Reenen M, Pillay B, Pillay M. M. tuberculosis curli pili (MTP) facilitates a reduction of microbicidal activity of infected THP-1 macrophages during early stages of infection. Comp Immunol Microbiol Infect Dis 2022; 90-91:101907. [DOI: 10.1016/j.cimid.2022.101907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 10/30/2022] [Accepted: 11/01/2022] [Indexed: 11/06/2022]
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7
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Allué-Guardia A, Garcia-Vilanova A, Olmo-Fontánez AM, Peters J, Maselli DJ, Wang Y, Turner J, Schlesinger LS, Torrelles JB. Host- and Age-Dependent Transcriptional Changes in Mycobacterium tuberculosis Cell Envelope Biosynthesis Genes after Exposure to Human Alveolar Lining Fluid. Int J Mol Sci 2022; 23:ijms23020983. [PMID: 35055170 PMCID: PMC8780516 DOI: 10.3390/ijms23020983] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 01/09/2022] [Accepted: 01/10/2022] [Indexed: 12/16/2022] Open
Abstract
Tuberculosis (TB) infection, caused by the airborne pathogen Mycobacterium tuberculosis (M.tb), resulted in almost 1.4 million deaths in 2019, and the number of deaths is predicted to increase by 20% over the next 5 years due to the COVID-19 pandemic. Upon reaching the alveolar space, M.tb comes into close contact with the lung mucosa before and after its encounter with host alveolar compartment cells. Our previous studies show that homeostatic, innate soluble components of the alveolar lining fluid (ALF) can quickly alter the cell envelope surface of M.tb upon contact, defining subsequent M.tb-host cell interactions and infection outcomes in vitro and in vivo. We also demonstrated that ALF from 60+ year old elders (E-ALF) vs. healthy 18- to 45-year-old adults (A-ALF) is dysfunctional, with loss of homeostatic capacity and impaired innate soluble responses linked to high local oxidative stress. In this study, a targeted transcriptional assay shows that M.tb exposure to human ALF alters the expression of its cell envelope genes. Specifically, our results indicate that A-ALF-exposed M.tb upregulates cell envelope genes associated with lipid, carbohydrate, and amino acid metabolism, as well as genes associated with redox homeostasis and transcriptional regulators. Conversely, M.tb exposure to E-ALF shows a lesser transcriptional response, with most of the M.tb genes unchanged or downregulated. Overall, this study indicates that M.tb responds and adapts to the lung alveolar environment upon contact, and that the host ALF status, determined by factors such as age, might play an important role in determining infection outcome.
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Affiliation(s)
- Anna Allué-Guardia
- Population Health Program, Texas Biomedical Research Institute, San Antonio, TX 78227, USA; (A.G.-V.); (A.M.O.-F.)
- Correspondence: (A.A.-G.); (J.B.T.)
| | - Andreu Garcia-Vilanova
- Population Health Program, Texas Biomedical Research Institute, San Antonio, TX 78227, USA; (A.G.-V.); (A.M.O.-F.)
| | - Angélica M. Olmo-Fontánez
- Population Health Program, Texas Biomedical Research Institute, San Antonio, TX 78227, USA; (A.G.-V.); (A.M.O.-F.)
- Integrated Biomedical Sciences Program, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Jay Peters
- Division of Pulmonary and Critical Care Medicine, School of Medicine, UT Health San Antonio, San Antonio, TX 78229, USA; (J.P.); (D.J.M.)
| | - Diego J. Maselli
- Division of Pulmonary and Critical Care Medicine, School of Medicine, UT Health San Antonio, San Antonio, TX 78229, USA; (J.P.); (D.J.M.)
| | - Yufeng Wang
- Department of Molecular Microbiology and Immunology, South Texas Center for Emerging Infectious Diseases, University of Texas at San Antonio, San Antonio, TX 78249, USA;
| | - Joanne Turner
- Host-Pathogen Interactions Program, Texas Biomedical Research Institute, San Antonio, TX 78227, USA; (J.T.); (L.S.S.)
| | - Larry S. Schlesinger
- Host-Pathogen Interactions Program, Texas Biomedical Research Institute, San Antonio, TX 78227, USA; (J.T.); (L.S.S.)
| | - Jordi B. Torrelles
- Population Health Program, Texas Biomedical Research Institute, San Antonio, TX 78227, USA; (A.G.-V.); (A.M.O.-F.)
- Correspondence: (A.A.-G.); (J.B.T.)
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8
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De P, Amin AG, Flores D, Simpson A, Dobos K, Chatterjee D. Structural implications of lipoarabinomannan glycans from global clinical isolates in diagnosis of Mycobacterium tuberculosis infection. J Biol Chem 2021; 297:101265. [PMID: 34600887 PMCID: PMC8531672 DOI: 10.1016/j.jbc.2021.101265] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 09/22/2021] [Accepted: 09/28/2021] [Indexed: 12/28/2022] Open
Abstract
In Mycobacterium tuberculosis (Mtb), surface-exposed Lipoarabinomannan (LAM) is a key determinant of immunogenicity, yet its intrinsic heterogeneity confounds typical structure–function analysis. Recently, LAM gained a strong foothold as a validated marker for active tuberculosis (TB) infection and has shown great potential in new diagnostic efforts. However, no efforts have yet been made to model or evaluate the impact of mixed polyclonal Mtb infections (infection with multiple strains) on TB diagnostic procedures other than antibiotic susceptibility testing. Here, we selected three TB clinical isolates (HN878, EAI, and IO) and purified LAM from these strains to present an integrated analytical approach of one-dimensional and two-dimensional Nuclear Magnetic Resonance (NMR) spectroscopy, as well as enzymatic digestion and site-specific mass spectrometry (MS) to probe LAM structure and behavior at multiple levels. Overall, we found that the glycan was similar in all LAM preparations, albeit with subtle variations. Succinates, lactates, hydroxybutyrate, acetate, and the hallmark of Mtb LAM-methylthioxylose (MTX), adorned the nonreducing terminal arabinan of these LAM species. Newly identified acetoxy/hydroxybutyrate was present only in LAM from EAI and IO Mtb strains. Notably, detailed LC/MS-MS unambiguously showed that all acyl modifications and the lactyl ether in LAM are at the 3-OH position of the 2-linked arabinofuranose adjacent to the terminal β-arabinofuranose. Finally, after sequential enzymatic deglycosylation of LAM, the residual glycan that has ∼50% of α−arabinofuranose -(1→5) linked did not bind to monoclonal antibody CS35. These data clearly indicate the importance of the arabinan termini arrangements for the antigenicity of LAM.
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Affiliation(s)
- Prithwiraj De
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Anita G Amin
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Danara Flores
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Anne Simpson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Karen Dobos
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA.
| | - Delphi Chatterjee
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA.
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9
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Allué-Guardia A, Garcia-Vilanova A, M Olmo-Fontánez A, Peters J, Maselli DJ, Wang Y, Turner J, Schlesinger LS, Torrelles JB. Host- and age-dependent transcriptional changes in Mycobacterium tuberculosis cell envelope biosynthesis genes after exposure to human alveolar lining fluid. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2021. [PMID: 34580670 DOI: 10.1101/2021.09.08.459334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Tuberculosis (TB) infection, caused by the airborne pathogen Mycobacterium tuberculosis ( M . tb ), resulted in almost 1.4 million deaths in 2019 and the number of deaths is predicted to increase by 20% over the next 5 years due to the COVID-19 pandemic. Upon reaching the alveolar space, M . tb comes in close contact with the lung mucosa before and after its encounter with host alveolar compartment cells. Our previous studies show that homeostatic innate soluble components of the alveolar lining fluid (ALF) can quickly alter the cell envelope surface of M . tb upon contact, defining subsequent M . tb -host cell interactions and infection outcomes in vitro and in vivo . We also demonstrated that ALF from 60+ year old elders (E-ALF) vs . healthy 18- to 45-year-old adults (A-ALF) is dysfunctional with loss of homeostatic capacity and impaired innate soluble responses linked to high local oxidative stress. In this study, a targeted transcriptional assay demonstrates that M . tb exposure to human ALF alters the expression of its cell envelope genes. Specifically, our results indicate that A-ALF-exposed M . tb upregulates cell envelope genes associated with lipid, carbohydrate, and amino acid metabolism, as well as genes associated with redox homeostasis and transcriptional regulators. Conversely, M . tb exposure to E-ALF shows lesser transcriptional response, with most of the M . tb genes unchanged or downregulated. Overall, this study indicates that M . tb responds and adapts to the lung alveolar environment upon contact, and that the host ALF status determined by factors such as age might play an important role in determining infection outcome.
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10
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Flores J, Cancino JC, Chavez-Galan L. Lipoarabinomannan as a Point-of-Care Assay for Diagnosis of Tuberculosis: How Far Are We to Use It? Front Microbiol 2021; 12:638047. [PMID: 33935997 PMCID: PMC8081860 DOI: 10.3389/fmicb.2021.638047] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 03/22/2021] [Indexed: 12/13/2022] Open
Abstract
Tuberculosis (TB) is still a severe public health problem; the current diagnostic tests have limitations that delay treatment onset. Lipoarabinomannan (LAM) is a glycolipid that is a component of the cell wall of the bacillus Mycobacterium tuberculosis, the etiologic agent of TB. This glycolipid is excreted as a soluble form in urine. The World Health Organization has established that the design of new TB diagnostic methods is one of the priorities within the EndTB Strategy. LAM has been suggested as a biomarker to develop diagnostic tests based on its identification in urine, and it is one of the most prominent candidates to develop point-of-care diagnostic test because urine samples can be easily collected. Moreover, LAM can regulate the immune response in the host and can be found in the serum of TB patients, where it probably affects a wide variety of host cell populations, consequently influencing the quality of both innate and adaptive immune responses during TB infection. Here, we revised the evidence that supports that LAM could be used as a tool for the development of new point-of-care tests for TB diagnosis, and we discussed the mechanisms that could contribute to the low sensitivity of diagnostic testing.
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Affiliation(s)
- Julio Flores
- Laboratory of Integrative Immunology, Instituto Nacional de Enfermedades Respiratorias Ismael Cosio Villegas, Mexico City, Mexico.,Laboratory of Immunomicrobiology, Department of Microbiology, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Juan Carlos Cancino
- Laboratory of Immunomicrobiology, Department of Microbiology, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Leslie Chavez-Galan
- Laboratory of Integrative Immunology, Instituto Nacional de Enfermedades Respiratorias Ismael Cosio Villegas, Mexico City, Mexico
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11
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Huang BS, Lowary TL. A Siloxane-Bridged Glycosyl Donor Enables Highly Stereoselective β-Xylulofuranosylation. J Org Chem 2020; 85:15895-15907. [PMID: 32489097 DOI: 10.1021/acs.joc.0c01008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
We report a siloxane-protected donor (7) for the highly stereoselective formation of β-(2,3-cis)-xylulofuranosyl bonds. Glycosylation reactions with 7 gave >80% yields, and only β-xylulofuranosides were isolated in all cases. The utility of 7 for the synthesis of complex glycans was shown by its successful application to the preparation of the repeating unit from the lipopolysaccharide O-antigen of Yersinia enterocolitica serovars O:5/O:5,27. This structure is a pentasaccharide with two β-xylulofuranose residues; using 7, both were introduced simultaneously with excellent stereocontrol.
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Affiliation(s)
- Bo-Shun Huang
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Todd L Lowary
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
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12
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Batt SM, Burke CE, Moorey AR, Besra GS. Antibiotics and resistance: the two-sided coin of the mycobacterial cell wall. Cell Surf 2020; 6:100044. [PMID: 32995684 PMCID: PMC7502851 DOI: 10.1016/j.tcsw.2020.100044] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/26/2020] [Accepted: 08/26/2020] [Indexed: 01/07/2023] Open
Abstract
Mycobacterium tuberculosis, the bacterium responsible for tuberculosis, is the global leading cause of mortality from an infectious agent. Part of this success relies on the unique cell wall, which consists of a thick waxy coat with tightly packed layers of complexed sugars, lipids and peptides. This coat provides a protective hydrophobic barrier to antibiotics and the host's defences, while enabling the bacterium to spread efficiently through sputum to infect and survive within the macrophages of new hosts. However, part of this success comes at a cost, with many of the current first- and second-line drugs targeting the enzymes involved in cell wall biosynthesis. The flip side of this coin is that resistance to these drugs develops either in the target enzymes or the activation pathways of the drugs, paving the way for new resistant clinical strains. This review provides a synopsis of the structure and synthesis of the cell wall and the major current drugs and targets, along with any mechanisms of resistance.
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Affiliation(s)
- Sarah M. Batt
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Christopher E. Burke
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Alice R. Moorey
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Gurdyal S. Besra
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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13
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Mavzyutov AR, Bondarenko KR, Mavzyutovа GA, Glazutdinova LR. [Clinical and laboratory parallels at pathological and borderline states associated with lipopolysaccharides.]. Klin Lab Diagn 2020; 65:29-36. [PMID: 32155004 DOI: 10.18821/0869-2084-2020-65-1-29-36] [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: 11/11/2019] [Accepted: 11/20/2019] [Indexed: 11/17/2022]
Abstract
The review systematizes data on the structure of lipopolysaccharides (LPS) and their role in physiological and systemic pathological processes. The analysis of literature and our own data is of scientific and practical interest for specialists in the field of clinical laboratory diagnostics, anesthesiologists, resuscitators, therapists, immunologists and obstetrician-gynecologists, including studies on the role of LPS in unique three-component systems - «mother-placenta-fetus». The prospects of using LPS as immunomodulatory, including for the treatment of infectious diseases, are justified. It is shown that along with their use for the correction of immunodeficiency or the development of new adjuvants and vaccines, it is possible to use their high regulatory activity even at the epigenetic level. The possibility of the prophylactic and therapeutic use of LPS in the context of an alternative solution to the problem of antibiotic resistance of bacteria is discussed.
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Affiliation(s)
- A R Mavzyutov
- Bashkir State Medical University, 450008, Ufa, Russia
| | - K R Bondarenko
- FGBOU IN RNIMU them. N.I. Pirogov of the Ministry of Health of Russia, 117997, Moscow, Russia
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14
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De P, Shi L, Boot C, Ordway D, McNeil M, Chatterjee D. Comparative Structural Study of Terminal Ends of Lipoarabinomannan from Mice Infected Lung Tissues and Urine of a Tuberculosis Positive Patient. ACS Infect Dis 2020; 6:291-301. [PMID: 31762254 DOI: 10.1021/acsinfecdis.9b00355] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Mycobacterium tuberculosis lipoarabinomannan (LAM) is a biomarker for active tuberculosis (TB) disease. The presence of LAM in the urine of TB patients, whether HIV positive or negative, has been validated by a gas chromatography/mass spectral method with good specificity (84%) and sensitivity (99%). However, point-of-care (POC) methods to detect TB LAM in urine using immunoassays have poor sensitivity and are limited to only HIV coinfected TB diagnosis. We hypothesized that these disappointing results with the POC methods may be due to the antibodies used in the immunoassays as there could be structural differences between LAM in vivo and LAM in vitro. To address this issue, we infected C3HeB/FeJ mice with M.tb W. Beijing SA161 and purified LAM from the lung. Analysis of these sources of LAM using a panel of existing mAbs revealed differences in epitope patterns. Conventionally, the non-reducing termini of LAM are identified by their release with endoarabinanase. These epitopes correspond to linear tetra-(Ara4), branched hexa-(Ara6) arabinofuranosides, and their mannose-capped versions. We discovered two distinct epitopes. In the first case, it was found that the non-reducing termini of LAM from M.tb strain SA161 are highly succinylated, especially when the LAM was isolated from the mouse lungs. In the second case, it was found that Cellulomonas endoarabinanase digestion of LAM from both SA161 and LAM from a TB+ HIV- patient's urine yielded epitopes based on 5 arabinoses as major components and a profound lack of Ara6. The epitopes based on 5 arabinoses from M.tb SA161 and from the LAM in human urine must result from underlying structural and thus epitope differences. These results suggest approaches to develop specific antibodies for POC tests for LAM in the urine of suspected TB patients.
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Affiliation(s)
- Prithwiraj De
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, 1682 Campus Delivery, Fort Collins, Colorado 80523, United States
| | - Libin Shi
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, 1682 Campus Delivery, Fort Collins, Colorado 80523, United States
| | - Claudia Boot
- Central Instrument Facility, Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Diane Ordway
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, 1682 Campus Delivery, Fort Collins, Colorado 80523, United States
| | - Michael McNeil
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, 1682 Campus Delivery, Fort Collins, Colorado 80523, United States
| | - Delphi Chatterjee
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, 1682 Campus Delivery, Fort Collins, Colorado 80523, United States
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15
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Madacki J, Mas Fiol G, Brosch R. Update on the virulence factors of the obligate pathogen Mycobacterium tuberculosis and related tuberculosis-causing mycobacteria. INFECTION GENETICS AND EVOLUTION 2019; 72:67-77. [DOI: 10.1016/j.meegid.2018.12.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 12/02/2018] [Accepted: 12/07/2018] [Indexed: 12/21/2022]
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16
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Bacterial carbohydrate diversity - a Brave New World. Curr Opin Chem Biol 2019; 53:1-8. [PMID: 31176085 DOI: 10.1016/j.cbpa.2019.04.026] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 04/29/2019] [Accepted: 04/30/2019] [Indexed: 12/11/2022]
Abstract
Glycans and glycoconjugates feature on the 'front line' of bacterial cells, playing critical roles in the mechanical and chemical stability of the microorganisms, and orchestrating interactions with the environment and all other living organisms. To negotiate such central tasks, bacterial glycomes incorporate a dizzying array of carbohydrate building blocks and non-carbohydrate modifications, which create opportunities for infinite structural variation. This review highlights some of the challenges and opportunities for the chemical biology community in the field of bacterial glycobiology.
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17
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Angala SK, Palčeková Z, Belardinelli JM, Jackson M. Covalent modifications of polysaccharides in mycobacteria. Nat Chem Biol 2019; 14:193-198. [PMID: 29443974 DOI: 10.1038/nchembio.2571] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Shiva K Angala
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Zuzana Palčeková
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Juan M Belardinelli
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Mary Jackson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
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18
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Chang Y, Meng X, Li Y, Liang J, Li T, Meng D, Zhu T, Yu P. Synthesis and immunogenicity of the Mycobacterium tuberculosis arabinomannan-CRM197 conjugate. MEDCHEMCOMM 2019; 10:543-553. [PMID: 31057734 DOI: 10.1039/c8md00546j] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Accepted: 02/15/2019] [Indexed: 01/06/2023]
Abstract
Lipoarabinomannan (LAM) is a major structural surface component of Mycobacterium tuberculosis. This study describes the synthesis of the well-defined lipoarabinomannan (LAM) specific dodecasaccharide-protein conjugate and immunological studies. Arabinomannan (AM) dodecasaccharide has been efficiently synthesized and covalently conjugated to carrier proteins, including cross reactive mutant (CRM197) diphtheria toxoid and bovine serum albumin (BSA) for novel neoglycoconjugates, creating a potent T-dependent conjugate vaccine. Preliminary mice immunization studies on the neoglycoconjugate revealed that it could give rise to a strong IgG antibody titer in mice at 4.0 μg dose with an aluminum phosphate adjuvant. AM-CRM197 shows potential as an excellent candidate for a new carbohydrate-based vaccine that would be capable of eliciting a protective immune response against tuberculosis.
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Affiliation(s)
- Yunsong Chang
- Key Laboratory of Industrial Microbiology , Ministry of Education , College of Biotechnology , Tianjin University of Science and Technology , Tianjin 300457 , PR China . ; ; ; Tel: +86 22 60912562
| | - Xin Meng
- Key Laboratory of Industrial Microbiology , Ministry of Education , College of Biotechnology , Tianjin University of Science and Technology , Tianjin 300457 , PR China . ; ; ; Tel: +86 22 60912562
| | - Yaxin Li
- Key Laboratory of Industrial Microbiology , Ministry of Education , College of Biotechnology , Tianjin University of Science and Technology , Tianjin 300457 , PR China . ; ; ; Tel: +86 22 60912562
| | - Jianmei Liang
- Key Laboratory of Industrial Microbiology , Ministry of Education , College of Biotechnology , Tianjin University of Science and Technology , Tianjin 300457 , PR China . ; ; ; Tel: +86 22 60912562
| | - Tingshen Li
- Key Laboratory of Industrial Microbiology , Ministry of Education , College of Biotechnology , Tianjin University of Science and Technology , Tianjin 300457 , PR China . ; ; ; Tel: +86 22 60912562
| | - Demei Meng
- State Key Laboratory of Food Nutrition and Safety , College of Food Engineering and Biotechnology , Tianjin University of Science & Technology , Tianjin , 300457 , PR China
| | - Tao Zhu
- Key Laboratory of Industrial Microbiology , Ministry of Education , College of Biotechnology , Tianjin University of Science and Technology , Tianjin 300457 , PR China . ; ; ; Tel: +86 22 60912562.,CanSino Biologics Inc. , Tianjin 300457 , PR China
| | - Peng Yu
- Key Laboratory of Industrial Microbiology , Ministry of Education , College of Biotechnology , Tianjin University of Science and Technology , Tianjin 300457 , PR China . ; ; ; Tel: +86 22 60912562
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19
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Kawasaki M, Echiverri C, Raymond L, Cadena E, Reside E, Gler MT, Oda T, Ito R, Higashiyama R, Katsuragi K, Liu Y. Lipoarabinomannan in sputum to detect bacterial load and treatment response in patients with pulmonary tuberculosis: Analytic validation and evaluation in two cohorts. PLoS Med 2019; 16:e1002780. [PMID: 30978194 PMCID: PMC6461223 DOI: 10.1371/journal.pmed.1002780] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 03/13/2019] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Lipoarabinomannan (LAM) is a major antigen of Mycobacterium tuberculosis (MTB). In this report, we evaluated the ability of a novel immunoassay to measure concentrations of LAM in sputum as a biomarker of bacterial load prior to and during treatment in pulmonary tuberculosis (TB) patients. METHODS AND FINDINGS Phage display technology was used to isolate monoclonal antibodies binding to epitopes unique in LAM from MTB and slow-growing nontuberculous mycobacteria (NTM). Using these antibodies, a sandwich enzyme-linked immunosorbent assay (LAM-ELISA) was developed to quantitate LAM concentration. The LAM-ELISA had a lower limit of quantification of 15 pg/mL LAM, corresponding to 121 colony-forming units (CFUs)/mL of MTB strain H37Rv. It detected slow-growing NTMs but without cross-reacting to common oral bacteria. Two clinical studies were performed between the years 2013 and 2016 in Manila, Philippines, in patients without known human immunodeficiency virus (HIV) coinfection. In a case-control cohort diagnostic study, sputum specimens were collected from 308 patients (aged 17-69 years; 62% male) diagnosed as having pulmonary TB diseases or non-TB diseases, but who could expectorate sputum, and were then evaluated by smear microscopy, BACTEC MGIT 960 Mycobacterial Detection System (MGIT) and Lowenstein-Jensen (LJ) culture, and LAM-ELISA. Some sputum specimens were also examined by Xpert MTB/RIF. The LAM-ELISA detected all smear- and MTB-culture-positive samples (n = 70) and 50% (n = 29) of smear-negative but culture-positive samples (n = 58) (versus 79.3%; 46 positive cases by the Xpert MTB/RIF), but none from non-TB patients (n = 56). Among both LAM and MGIT MTB-culture-positive samples, log10-transformed LAM concentration and MGIT time to detection (TTD) showed a good inverse relationship (r = -0.803, p < 0.0001). In a prospective longitudinal cohort study, 40 drug-susceptible pulmonary TB patients (aged 18-69 years; 60% male) were enrolled during the first 56 days of the standard 4-drug therapy. Declines in sputum LAM concentrations correlated with increases of MGIT TTD in individual patients. There was a 1.29 log10 decrease of sputum LAM concentration, corresponding to an increase of 221 hours for MGIT TTD during the first 14 days of treatment, a treatment duration often used in early bactericidal activity (EBA) trials. Major limitations of this study include a relatively small number of patients, treatment duration up to only 56 days, lack of quantitative sputum culture CFU count data, and no examination of the correlation of sputum LAM to clinical cure. CONCLUSIONS These results indicate that the LAM-ELISA can determine LAM concentration in sputum, and sputum LAM measured by the assay may be used as a biomarker of bacterial load prior to and during TB treatment. Additional studies are needed to examine the predictive value of this novel biomarker on treatment outcomes.
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Affiliation(s)
| | | | - Lawrence Raymond
- Lung Center of the Philippines, Quezon City, Metro Manila, Philippines
| | - Elizabeth Cadena
- Jose R. Reyes Memorial Medical Center, Manila City, Metro Manila, Philippines
| | - Evelyn Reside
- The Medical City, Pasig City, Metro Manila, Philippines
| | - Maria Tarcela Gler
- Otsuka Manila Research Center, Otsuka (Philippines) Pharmaceutical, Makati City, Metro Manila, Philippines
| | | | - Ryuta Ito
- Otsuka Pharmaceutical Company, Tokyo, Japan
| | | | | | - Yongge Liu
- Otsuka Pharmaceutical Development & Commercialization, Rockville, Maryland, United States of America
- * E-mail:
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20
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A Novel Sensitive Immunoassay Targeting the 5-Methylthio-d-Xylofuranose-Lipoarabinomannan Epitope Meets the WHO's Performance Target for Tuberculosis Diagnosis. J Clin Microbiol 2018; 56:JCM.01338-18. [PMID: 30257899 PMCID: PMC6258851 DOI: 10.1128/jcm.01338-18] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Accepted: 09/19/2018] [Indexed: 12/30/2022] Open
Abstract
The only currently commercialized point-of-care assay for tuberculosis (TB) that measures lipoarabinomannan (LAM) in urine (Alere LF-LAM) has insufficient sensitivity. We evaluated the potential of 100 novel monoclonal antibody pairs targeting a variety of LAM epitopes on a sensitive electrochemiluminescence platform to improve the diagnostic accuracy. The only currently commercialized point-of-care assay for tuberculosis (TB) that measures lipoarabinomannan (LAM) in urine (Alere LF-LAM) has insufficient sensitivity. We evaluated the potential of 100 novel monoclonal antibody pairs targeting a variety of LAM epitopes on a sensitive electrochemiluminescence platform to improve the diagnostic accuracy. In the screening, many antibody pairs showed high reactivity to purified LAM but performed poorly at detecting urinary LAM in clinical samples, suggesting differences in antigen structure and immunoreactivity of the different LAM sources. The 12 best antibody pairs from the screening were tested in a retrospective case-control study with urine samples from 75 adults with presumptive TB. The best antibody pair reached femtomolar analytical sensitivity for LAM detection and an overall clinical sensitivity of 93% (confidence interval [CI], 80% to 97%) and specificity of 97% (CI, 85% to 100%). Importantly, in HIV-negative subjects positive for TB by sputum smear microscopy, the test achieved a sensitivity of 80% (CI, 55% to 93%). This compares to an overall sensitivity of 33% (CI, 20% to 48%) of the Alere LF-LAM and a sensitivity of 13% (CI, 4% to 38%) in HIV-negative subjects in the same sample set. The capture antibody targets a unique 5-methylthio-d-xylofuranose (MTX)-dependent epitope in LAM that is specific to the Mycobacterium tuberculosis complex and shows no cross-reactivity with fast-growing mycobacteria or other bacteria. The present study provides evidence that improved assay methods and reagents lead to increased diagnostic accuracy. The results of this work have informed the development of a sensitive and specific novel LAM point-of-care assay with the aim to meet the WHO's performance target for TB diagnosis.
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21
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Zhang L, Shen K, Taha HA, Lowary TL. Stereocontrolled Synthesis of α-Xylofuranosides Using a Conformationally Restricted Donor. J Org Chem 2018. [PMID: 29895148 DOI: 10.1021/acs.joc.8b00410.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A number of biologically relevant glycoconjugates possess 1,2- cis-furanosidic linkages, a class of glycosidic bond that remains challenging to introduce with high stereoselectivity. In this paper, we report an approach to one family of such linkages, α-xylofuranosides, via the use of thioglycoside donors possessing a conformationally restricting xylylene protecting group. The method was shown to provide the desired targets in good to excellent yield and stereoselectivity. Computational investigations support the proposal that the protecting group locks the electrophilic intermediate in these reactions into a conformation that leads to the high selectivity. The power of the methodology was demonstrated through the synthesis of a complex hexasaccharide motif from lipoarabinomannan, an immunomodulatory polysaccharide from mycobacteria.
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Affiliation(s)
- Li Zhang
- Alberta Glycomics Centre and Department of Chemistry , University of Alberta , 11227 Saskatchewan Drive , Edmonton , Alberta T6G 2G2 , Canada
| | - Ke Shen
- Alberta Glycomics Centre and Department of Chemistry , University of Alberta , 11227 Saskatchewan Drive , Edmonton , Alberta T6G 2G2 , Canada
| | - Hashem A Taha
- Alberta Glycomics Centre and Department of Chemistry , University of Alberta , 11227 Saskatchewan Drive , Edmonton , Alberta T6G 2G2 , Canada
| | - Todd L Lowary
- Alberta Glycomics Centre and Department of Chemistry , University of Alberta , 11227 Saskatchewan Drive , Edmonton , Alberta T6G 2G2 , Canada
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22
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Zhang L, Shen K, Taha HA, Lowary TL. Stereocontrolled Synthesis of α-Xylofuranosides Using a Conformationally Restricted Donor. J Org Chem 2018; 83:7659-7671. [PMID: 29895148 PMCID: PMC6079929 DOI: 10.1021/acs.joc.8b00410] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
![]()
A number of biologically relevant
glycoconjugates possess 1,2-cis-furanosidic linkages,
a class of glycosidic bond that
remains challenging to introduce with high stereoselectivity. In this
paper, we report an approach to one family of such linkages, α-xylofuranosides,
via the use of thioglycoside donors possessing a conformationally
restricting xylylene protecting group. The method was shown to provide
the desired targets in good to excellent yield and stereoselectivity.
Computational investigations support the proposal that the protecting
group locks the electrophilic intermediate in these reactions into
a conformation that leads to the high selectivity. The power of the
methodology was demonstrated through the synthesis of a complex hexasaccharide
motif from lipoarabinomannan, an immunomodulatory polysaccharide from
mycobacteria.
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Affiliation(s)
- Li Zhang
- Alberta Glycomics Centre and Department of Chemistry , University of Alberta , 11227 Saskatchewan Drive , Edmonton , Alberta T6G 2G2 , Canada
| | - Ke Shen
- Alberta Glycomics Centre and Department of Chemistry , University of Alberta , 11227 Saskatchewan Drive , Edmonton , Alberta T6G 2G2 , Canada
| | - Hashem A Taha
- Alberta Glycomics Centre and Department of Chemistry , University of Alberta , 11227 Saskatchewan Drive , Edmonton , Alberta T6G 2G2 , Canada
| | - Todd L Lowary
- Alberta Glycomics Centre and Department of Chemistry , University of Alberta , 11227 Saskatchewan Drive , Edmonton , Alberta T6G 2G2 , Canada
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23
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Choudhary A, Patel D, Honnen W, Lai Z, Prattipati RS, Zheng RB, Hsueh YC, Gennaro ML, Lardizabal A, Restrepo BI, Garcia-Viveros M, Joe M, Bai Y, Shen K, Sahloul K, Spencer JS, Chatterjee D, Broger T, Lowary TL, Pinter A. Characterization of the Antigenic Heterogeneity of Lipoarabinomannan, the Major Surface Glycolipid of Mycobacterium tuberculosis, and Complexity of Antibody Specificities toward This Antigen. THE JOURNAL OF IMMUNOLOGY 2018; 200:3053-3066. [PMID: 29610143 PMCID: PMC5911930 DOI: 10.4049/jimmunol.1701673] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 02/16/2018] [Indexed: 12/17/2022]
Abstract
Lipoarabinomannan (LAM), the major antigenic glycolipid of Mycobacterium tuberculosis, is an important immunodiagnostic target for detecting tuberculosis (TB) infection in HIV-1–coinfected patients, and is believed to mediate a number of functions that promote infection and disease development. To probe the human humoral response against LAM during TB infection, several novel LAM-specific human mAbs were molecularly cloned from memory B cells isolated from infected patients and grown in vitro. The fine epitope specificities of these Abs, along with those of a panel of previously described murine and phage-derived LAM-specific mAbs, were mapped using binding assays against LAM Ags from several mycobacterial species and a panel of synthetic glycans and glycoconjugates that represented diverse carbohydrate structures present in LAM. Multiple reactivity patterns were seen that differed in their specificity for LAM from different species, as well as in their dependence on arabinofuranoside branching and nature of capping at the nonreducing termini. Competition studies with mAbs and soluble glycans further defined these epitope specificities and guided the design of highly sensitive immunodetection assays capable of detecting LAM in urine of TB patients, even in the absence of HIV-1 coinfection. These results highlighted the complexity of the antigenic structure of LAM and the diversity of the natural Ab response against this target. The information and novel reagents described in this study will allow further optimization of diagnostic assays for LAM and may facilitate the development of potential immunotherapeutic approaches to inhibit the functional activities of specific structural motifs in LAM.
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Affiliation(s)
- Alok Choudhary
- Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103
| | - Deendayal Patel
- Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103
| | - William Honnen
- Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103
| | - Zhong Lai
- Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103
| | - Raja Sekhar Prattipati
- Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103
| | - Ruixiang Blake Zheng
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Ying-Chao Hsueh
- Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103
| | - Maria Laura Gennaro
- Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103
| | - Alfred Lardizabal
- Global Tuberculosis Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103
| | - Blanca I Restrepo
- University of Texas Health Science Center at Houston, School of Public Health at Brownsville, Brownsville, TX 78520
| | | | - Maju Joe
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Yu Bai
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Ke Shen
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Kamar Sahloul
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - John S Spencer
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO 80523; and
| | - Delphi Chatterjee
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO 80523; and
| | - Tobias Broger
- Foundation for Innovative New Diagnostics, Geneva 1202, Switzerland
| | - Todd L Lowary
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Abraham Pinter
- Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103;
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