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Bonhomme D, Werts C. Host and Species-Specificities of Pattern Recognition Receptors Upon Infection With Leptospira interrogans. Front Cell Infect Microbiol 2022; 12:932137. [PMID: 35937697 PMCID: PMC9353586 DOI: 10.3389/fcimb.2022.932137] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 06/24/2022] [Indexed: 12/12/2022] Open
Abstract
Leptospirosis is a zoonotic infectious disease affecting all vertebrates. It is caused by species of the genus Leptospira, among which are the highly pathogenic L. interrogans. Different mammals can be either resistant or susceptible to the disease which can present a large variety of symptoms. Humans are mostly asymptomatic after infection but can have in some cases symptoms varying from a flu-like syndrome to more severe forms such as Weil’s disease, potentially leading to multiorgan failure and death. Similarly, cattle, pigs, and horses can suffer from acute forms of the disease, including morbidity, abortion, and uveitis. On the other hand, mice and rats are resistant to leptospirosis despite chronical colonization of the kidneys, excreting leptospires in urine and contributing to the transmission of the bacteria. To this date, the immune mechanisms that determine the severity of the infection and that confer susceptibility to leptospirosis remain enigmatic. To our interest, differential immune sensing of leptospires through the activation of or escape from pattern recognition receptors (PRRs) by microbe-associated molecular patterns (MAMPs) has recently been described. In this review, we will summarize these findings that suggest that in various hosts, leptospires differentially escape recognition by some Toll-like and NOD-like receptors, including TLR4, TLR5, and NOD1, although TLR2 and NLRP3 responses are conserved independently of the host. Overall, we hypothesize that these innate immune mechanisms could play a role in determining host susceptibility to leptospirosis and suggest a central, yet complex, role for TLR4.
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2
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Ghosh M, Basak S, Dutta S. Natural selection shaped the evolution of amino acid usage in mammalian toll like receptor genes. Comput Biol Chem 2022; 97:107637. [DOI: 10.1016/j.compbiolchem.2022.107637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 11/09/2021] [Accepted: 01/30/2022] [Indexed: 11/03/2022]
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Amemiya K, Dankmeyer JL, Bernhards RC, Fetterer DP, Waag DM, Worsham PL, DeShazer D. Activation of Toll-Like Receptors by Live Gram-Negative Bacterial Pathogens Reveals Mitigation of TLR4 Responses and Activation of TLR5 by Flagella. Front Cell Infect Microbiol 2021; 11:745325. [PMID: 34888257 PMCID: PMC8650638 DOI: 10.3389/fcimb.2021.745325] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 10/18/2021] [Indexed: 12/27/2022] Open
Abstract
Successful bacterial pathogens have evolved to avoid activating an innate immune system in the host that responds to the pathogen through distinct Toll-like receptors (TLRs). The general class of biochemical components that activate TLRs has been studied extensively, but less is known about how TLRs interact with the class of compounds that are still associated with the live pathogen. Accordingly, we examined the activation of surface assembled TLR 2, 4, and 5 with live Tier 1 Gram-negative pathogens that included Yersinia pestis (plague), Burkholderia mallei (glanders), Burkholderia pseudomallei (melioidosis), and Francisella tularensis (tularemia). We found that Y. pestis CO92 grown at 28°C activated TLR2 and TLR4, but at 37°C the pathogen activated primarily TLR2. Although B. mallei and B. pseudomallei are genetically related, the former microorganism activated predominately TLR4, while the latter activated predominately TLR2. The capsule of wild-type B. pseudomallei 1026b was found to mitigate the activation of TLR2 and TLR4 when compared to a capsule mutant. Live F. tularensis (Ft) Schu S4 did not activate TLR2 or 4, although the less virulent Ft LVS and F. novicida activated only TLR2. B. pseudomallei purified flagellin or flagella attached to the microorganism activated TLR5. Activation of TLR5 was abolished by an antibody to TLR5, or a mutation of fliC, or elimination of the pathogen by filtration. In conclusion, we have uncovered new properties of the Gram-negative pathogens, and their interaction with TLRs of the host. Further studies are needed to include other microorganism to extend our observations with their interaction with TLRs, and to the possibility of leading to new efforts in therapeutics against these pathogens.
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Affiliation(s)
- Kei Amemiya
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD, United States
| | - Jennifer L Dankmeyer
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD, United States
| | - Robert C Bernhards
- Edgewood Chemical Biological Centre, Aberdeen Proving Ground, Edgewood, MD, United States
| | - David P Fetterer
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD, United States
| | - David M Waag
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD, United States
| | - Patricia L Worsham
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD, United States
| | - David DeShazer
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD, United States
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4
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Gao Q, Yi S, Luo J, Xing Q, Lv J, Wang P, Wang C, Li Y. Construction of a Vibrio anguillarum flagellin B mutant and analysis of its immuno-stimulation effects on Macrobrachium rosenbergii. Int J Biol Macromol 2021; 174:457-465. [PMID: 33493561 DOI: 10.1016/j.ijbiomac.2021.01.146] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 01/20/2021] [Accepted: 01/20/2021] [Indexed: 01/16/2023]
Abstract
Vibrio anguillarum is a globally distributed aquatic pathogen, and its flagellin B (FlaB) protein can evoke innate immune responses in hosts. In order to explore the role of FlaB in V. anguillarum infection, we constructed a FlaB-deficient mutant using overlapping PCR and two-step homologous recombination, and gene sequencing confirmed successful knockout of the FlaB gene. Scanning electron microscopy showed no significant differences in the morphological structure of the flagellum between wild-type and FlaB-deficient strains. The mutant was subsequently injected into the freshwater prawn (Macrobrachium rosenbergii) to explore its pathogenicity in the host, and expression of myeloid differentiation factor 88, prophenoloxidase, catalase, superoxide dismutase and glutathione peroxidase was investigated by real-time PCR. The results showed that deletion of FlaB had little effect on V. anguillarum-induced expression of these immune-related genes (p > 0.05). In general, the FlaB mutant displayed similar flagella morphology and immune characteristics to the wild-type strain, hence we speculated that knockout of FlaB might promote the expression and function of other flagellin proteins. Furthermore, this study provides a rapid and simple method for obtaining stable mutants of V. anguillarum free from foreign plasmid DNA.
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Affiliation(s)
- Quanxin Gao
- Zhejiang Provincial Key Laboratory of Aquatic Resources Conservation and Development, Key Laboratory of Aquatic Animal Genetic Breeding and Nutrition, Chinese Academy of Fishery Sciences, Huzhou Cent Hosp, Huzhou University, College of Life Science, Huzhou University, Huzhou 313000, PR China
| | - Shaokui Yi
- Zhejiang Provincial Key Laboratory of Aquatic Resources Conservation and Development, Key Laboratory of Aquatic Animal Genetic Breeding and Nutrition, Chinese Academy of Fishery Sciences, Huzhou Cent Hosp, Huzhou University, College of Life Science, Huzhou University, Huzhou 313000, PR China
| | - Jinping Luo
- Zhejiang Provincial Key Laboratory of Aquatic Resources Conservation and Development, Key Laboratory of Aquatic Animal Genetic Breeding and Nutrition, Chinese Academy of Fishery Sciences, Huzhou Cent Hosp, Huzhou University, College of Life Science, Huzhou University, Huzhou 313000, PR China
| | - Qianqian Xing
- Zhejiang Provincial Key Laboratory of Aquatic Resources Conservation and Development, Key Laboratory of Aquatic Animal Genetic Breeding and Nutrition, Chinese Academy of Fishery Sciences, Huzhou Cent Hosp, Huzhou University, College of Life Science, Huzhou University, Huzhou 313000, PR China
| | - Jiali Lv
- Zhejiang Provincial Key Laboratory of Aquatic Resources Conservation and Development, Key Laboratory of Aquatic Animal Genetic Breeding and Nutrition, Chinese Academy of Fishery Sciences, Huzhou Cent Hosp, Huzhou University, College of Life Science, Huzhou University, Huzhou 313000, PR China
| | - Panhuang Wang
- Zhejiang Provincial Key Laboratory of Aquatic Resources Conservation and Development, Key Laboratory of Aquatic Animal Genetic Breeding and Nutrition, Chinese Academy of Fishery Sciences, Huzhou Cent Hosp, Huzhou University, College of Life Science, Huzhou University, Huzhou 313000, PR China
| | - Cuihua Wang
- Key Laboratory of Marine and Estuarine Fisheries, Ministry of Agriculture, East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai 200090, People's Republic of China.
| | - Yang Li
- Zhejiang Provincial Key Laboratory of Aquatic Resources Conservation and Development, Key Laboratory of Aquatic Animal Genetic Breeding and Nutrition, Chinese Academy of Fishery Sciences, Huzhou Cent Hosp, Huzhou University, College of Life Science, Huzhou University, Huzhou 313000, PR China.
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5
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Holzapfel M, Bonhomme D, Cagliero J, Vernel-Pauillac F, Fanton d'Andon M, Bortolussi S, Fiette L, Goarant C, Wunder EA, Picardeau M, Ko AI, Werling D, Matsui M, Boneca IG, Werts C. Escape of TLR5 Recognition by Leptospira spp.: A Rationale for Atypical Endoflagella. Front Immunol 2020; 11:2007. [PMID: 32849665 PMCID: PMC7431986 DOI: 10.3389/fimmu.2020.02007] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 07/24/2020] [Indexed: 12/26/2022] Open
Abstract
Leptospira (L.) interrogans are invasive bacteria responsible for leptospirosis, a worldwide zoonosis. They possess two periplasmic endoflagellae that allow their motility. L. interrogans are stealth pathogens that escape the innate immune recognition of the NOD-like receptors NOD1/2, and the human Toll-like receptor (TLR)4, which senses peptidoglycan and lipopolysaccharide (LPS), respectively. TLR5 is another receptor of bacterial cell wall components, recognizing flagellin subunits. To study the contribution of TLR5 in the host defense against leptospires, we infected WT and TLR5 deficient mice with pathogenic L. interrogans and tracked the infection by in vivo live imaging of bioluminescent bacteria or by qPCR. We did not identify any protective or inflammatory role of murine TLR5 for controlling pathogenic Leptospira. Likewise, subsequent in vitro experiments showed that infections with different live strains of L. interrogans and L. biflexa did not trigger TLR5 signaling. However, unexpectedly, heat-killed bacteria stimulated human and bovine TLR5, but did not, or barely induced stimulation via murine TLR5. Abolition of TLR5 recognition required extensive boiling time of the bacteria or proteinase K treatment, showing an unusual high stability of the leptospiral flagellins. Interestingly, after using antimicrobial peptides to destabilize live leptospires, we detected TLR5 activity, suggesting that TLR5 could participate in the fight against leptospires in humans or cattle. Using different Leptospira strains with mutations in the flagellin proteins, we further showed that neither FlaA nor Fcp participated in the recognition by TLR5, suggesting a role for the FlaB. FlaB have structural homology to Salmonella FliC, and possess conserved residues important for TLR5 activation, as shown by in silico analyses. Accordingly, we found that leptospires regulate the expression of FlaB mRNA according to the growth phase in vitro, and that infection with L. interrogans in hamsters and in mice downregulated the expression of the FlaB, but not the FlaA subunits. Altogether, in contrast to different bacteria that modify their flagellin sequences to escape TLR5 recognition, our study suggests that the peculiar central localization and stability of the FlaB monomers in the periplasmic endoflagellae, associated with the downregulation of FlaB subunits in hosts, constitute an efficient strategy of leptospires to escape the TLR5 recognition and the induced immune response.
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Affiliation(s)
- Marion Holzapfel
- Institut Pasteur, Unité Biologie et Génétique de la Paroi Bactérienne, Paris, France.,CNRS, UMR 2001 Microbiologie Intégrative et Moléculaire, Paris, France.,Institut National de la Santé et de la Recherche Médicale, Equipe Avenir, Paris, France
| | - Delphine Bonhomme
- Institut Pasteur, Unité Biologie et Génétique de la Paroi Bactérienne, Paris, France.,CNRS, UMR 2001 Microbiologie Intégrative et Moléculaire, Paris, France.,Institut National de la Santé et de la Recherche Médicale, Equipe Avenir, Paris, France.,Sorbonne Paris Cité, Université de Paris, Paris, France
| | - Julie Cagliero
- Institut Pasteur de Nouvelle Calédonie, Immunity and Inflammation Group, Institut Pasteur International Network, Noumea, France
| | - Frédérique Vernel-Pauillac
- Institut Pasteur, Unité Biologie et Génétique de la Paroi Bactérienne, Paris, France.,CNRS, UMR 2001 Microbiologie Intégrative et Moléculaire, Paris, France.,Institut National de la Santé et de la Recherche Médicale, Equipe Avenir, Paris, France
| | - Martine Fanton d'Andon
- Institut Pasteur, Unité Biologie et Génétique de la Paroi Bactérienne, Paris, France.,CNRS, UMR 2001 Microbiologie Intégrative et Moléculaire, Paris, France.,Institut National de la Santé et de la Recherche Médicale, Equipe Avenir, Paris, France
| | - Sophia Bortolussi
- Institut Pasteur, Unité Biologie et Génétique de la Paroi Bactérienne, Paris, France.,CNRS, UMR 2001 Microbiologie Intégrative et Moléculaire, Paris, France.,Institut National de la Santé et de la Recherche Médicale, Equipe Avenir, Paris, France
| | - Laurence Fiette
- Unité Histopathologie Humaine et Modèles Animaux, Institut Pasteur, Paris, France
| | - Cyrille Goarant
- Leptospirosis Research and Expertise Unit, Institut Pasteur International Network, Institut Pasteur de Nouvelle Calédonie, Noumea, France
| | - Elsio A Wunder
- Gonçalo Moniz Institute, Oswaldo Cruz Foundation, Brazilian Ministry of Health, Salvador, Brazil.,Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, United States
| | | | - Albert I Ko
- Gonçalo Moniz Institute, Oswaldo Cruz Foundation, Brazilian Ministry of Health, Salvador, Brazil.,Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, United States
| | - Dirk Werling
- Department of Pathobiology and Population Sciences, Royal Veterinary College, Hatfield, United Kingdom
| | - Mariko Matsui
- Institut Pasteur de Nouvelle Calédonie, Immunity and Inflammation Group, Institut Pasteur International Network, Noumea, France
| | - Ivo G Boneca
- Institut Pasteur, Unité Biologie et Génétique de la Paroi Bactérienne, Paris, France.,CNRS, UMR 2001 Microbiologie Intégrative et Moléculaire, Paris, France.,Institut National de la Santé et de la Recherche Médicale, Equipe Avenir, Paris, France
| | - Catherine Werts
- Institut Pasteur, Unité Biologie et Génétique de la Paroi Bactérienne, Paris, France.,CNRS, UMR 2001 Microbiologie Intégrative et Moléculaire, Paris, France.,Institut National de la Santé et de la Recherche Médicale, Equipe Avenir, Paris, France
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6
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Recombinant flagellins with deletions in domains D1, D2, and D3: Characterization as novel immunoadjuvants. Vaccine 2018; 37:652-663. [PMID: 30583910 DOI: 10.1016/j.vaccine.2018.12.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 11/29/2018] [Accepted: 12/02/2018] [Indexed: 12/17/2022]
Abstract
Bacterial flagellin activates the innate immune system and ultimately the adaptive immune system through a Toll-like receptor 5 (TLR5)-dependent signaling mechanism. Given that TLR5 is widely distributed in epithelia, flagellin is currently being developed as a mucosal adjuvant. Flagellin FliC from Salmonella enterica has four domains: the conserved D0 and D1 domains and the hypervariable D2 and D3 domains. The deletion of D3 and partial deletion of D2 in the recombinant FliCΔ174-400 strongly impairs flagellin's intrinsic antigenicity but does not affect the TLR5-dependent immunostimulation activity, i.e., the capacity to promote innate responses and adaptive responses to co-administered antigens. Here, we describe the development of novel recombinant flagellins with various deletions encompassing all of D2 and D3, and part of D1. Most of the recombinant molecules conserved an α-helical secondary structure that was as resistant to heat denaturation as the native protein. Whereas the recombinant flagellins' ability to trigger TLR5 varied markedly in vitro, most gave equivalent in vivo TLR5-dependent innate immune responses following intranasal administration of 2 μg of flagellin to mice. Concordantly, the recombinant flagellins were also valuable respiratory adjuvants for eliciting antibody responses to the foreign antigen ovalbumin, although their intrinsic antigenicity was decreased compared to the native flagellin and not increased compared to FliCΔ174-400. Our results show that the additional deletions of D2 and the distal part of D1 of FliCΔ174-400 does not impact on antigenicity and does not significantly modify the immunostimulatory adjuvant activity. Altogether, this study generated a novel set of recombinant flagellin that constitutes a portfolio of TLR5-dependent candidate adjuvants for vaccination.
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7
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Faber E, Tedin K, Speidel Y, Brinkmann MM, Josenhans C. Functional expression of TLR5 of different vertebrate species and diversification in intestinal pathogen recognition. Sci Rep 2018; 8:11287. [PMID: 30050158 PMCID: PMC6062626 DOI: 10.1038/s41598-018-29371-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 07/10/2018] [Indexed: 12/12/2022] Open
Abstract
Toll-like receptor 5 (TLR5) is activated by bacterial flagellins and plays a crucial role in the first-line defence against pathogenic bacteria and in immune homeostasis, and is highly conserved in vertebrate species. However, little comparative information is available on TLR5 functionality. In this study, we compared TLR5 activation using full-length and chimeric TLR5 of various vertebrate species (human, chicken, mouse, pig, cattle). Chimeric TLR5 receptors, consisting of human transmembrane and intracellular domains, linked to extracellular domains of animal origin, were generated and expressed. The comparison of chimeric TLR5s and their full-length counterparts revealed significant functional disparities. While porcine and chicken full-length TLR5s showed a strongly reduced functionality in human cells, all chimeric receptors were functional when challenged with TLR5 ligand Salmonella FliC. Using chimeric receptors as a tool allowed for the identification of ectodomain-dependent activation potential and partially host species-specific differences in response to various enteric bacterial strains and their purified flagellins. We conclude that both the extra- and intracellular determinants of TLR5 receptors are crucial for compatibility with the species expression background and hence for proper receptor functionality. TLR5 receptors with a common intracellular domain provide a useful system to investigate bacteria- and host-specific differences in receptor activation.
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Affiliation(s)
- Eugenia Faber
- Medizinische Hochschule Hannover, Institute for Medical Microbiology, Carl-Neuberg-Strasse 1, 30625, Hannover, Germany.,DZIF-German Center for Infection Research, Partner site Hannover-Braunschweig, Hannover, Germany
| | - Karsten Tedin
- Institute of Microbiology and Epizootics, Free University Berlin, Robert-von-Ostertag-Strasse 7-13, 14163, Berlin, Germany
| | - Yvonne Speidel
- Medizinische Hochschule Hannover, Institute for Medical Microbiology, Carl-Neuberg-Strasse 1, 30625, Hannover, Germany.,DZIF-German Center for Infection Research, Partner site Hannover-Braunschweig, Hannover, Germany
| | - Melanie M Brinkmann
- Helmholtz Center for Infection Research, Inhoffenstrasse 7, 38124, Braunschweig, Germany
| | - Christine Josenhans
- Medizinische Hochschule Hannover, Institute for Medical Microbiology, Carl-Neuberg-Strasse 1, 30625, Hannover, Germany. .,DZIF-German Center for Infection Research, Partner site Hannover-Braunschweig, Hannover, Germany. .,Max von Pettenkofer Institute, Ludwig Maximilians University Munich, Pettenkoferstrasse 9a, 80336, Munich, Germany.
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8
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Harris VC. The Significance of the Intestinal Microbiome for Vaccinology: From Correlations to Therapeutic Applications. Drugs 2018; 78:1063-1072. [PMID: 29943376 PMCID: PMC6061423 DOI: 10.1007/s40265-018-0941-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Despite unprecedented advances in understanding the intestinal microbiome, its potential to improve fields such as vaccinology has yet to be realized. This review briefly outlines the immunologic potential of the intestinal microbiome for vaccinology and highlights areas where the microbiome holds specific promise in vaccinology. Oral rotavirus vaccine effectiveness in low-income countries is used as a case study to describe how the intestinal microbiome may be employed to improve a vaccine's immunogenicity. A top-down, evidence-based approach is proposed to identify effective microbiota-based applications for vaccine improvement. Applying evidence from field studies in pertinent populations that correlate microbiome composition with vaccine effectiveness to appropriate experimental platforms will lead to the identification of safe, vaccine-supporting microbiota targets that are relevant to populations in need of improvement in vaccine-induced immunity.
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Affiliation(s)
- Vanessa C Harris
- Amsterdam Institute for Global Health and Development (AIGHD), Amsterdam, The Netherlands.
- Department of Medicine, Division of Infectious Diseases and Center for Experimental and Molecular Medicine (CEMM), Academic Medical Center, Amsterdam, The Netherlands.
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9
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Ivičak-Kocjan K, Forstnerič V, Panter G, Jerala R, Benčina M. Extension and refinement of the recognition motif for Toll-like receptor 5 activation by flagellin. J Leukoc Biol 2018; 104:767-776. [PMID: 29920759 DOI: 10.1002/jlb.3vma0118-035r] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 04/24/2018] [Accepted: 05/16/2018] [Indexed: 11/07/2022] Open
Abstract
TLRs sense conserved and essential molecular components of microbes that invade multicellular organisms. The wide range of TLR agonists, differing in size and shape, is recognized either through a single or a pair of binding sites on the ectodomains of TLRs. TLR5 recognizes bacterial flagellin through two distinct binding sites on the ectodomain, the first facilitating primary binding of flagellin and the second guiding receptor dimerization necessary for signaling. The regions of flagellin recognized by TLR5 encompass key functional regions within the D1 domain of flagellin, which is also required for the assembly of functional flagella. In addition to previously identified binding sites at the N-terminal and central segment of the TLR5 ectodomain, we extended the TLR5'-D1 interaction interface on TLR5 and showed a species-specific recognition relevance of this extended region. In addition, we showed that the loop and following β-hairpin region of flagellin, previously proposed to participate in the TLR5-flagellin dimerization interface, is not accountable for these species-specific differences. We further identified residues that contribute to the interaction between two TLR5 ectodomains in an active signaling complex. Our work demonstrates that flagellin is recognized by TLR5 through a more extensive interaction surface than previously characterized.
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Affiliation(s)
- Karolina Ivičak-Kocjan
- Department of Synthetic Biology and Immunology, National Institute of Chemistry, Ljubljana, Slovenia
| | - Vida Forstnerič
- Department of Synthetic Biology and Immunology, National Institute of Chemistry, Ljubljana, Slovenia
| | - Gabriela Panter
- Department of Synthetic Biology and Immunology, National Institute of Chemistry, Ljubljana, Slovenia
| | - Roman Jerala
- Department of Synthetic Biology and Immunology, National Institute of Chemistry, Ljubljana, Slovenia
- Centre of Excellence EN-FIST, Ljubljana, Slovenia
| | - Mojca Benčina
- Department of Synthetic Biology and Immunology, National Institute of Chemistry, Ljubljana, Slovenia
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10
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Koosakulnirand S, Phokrai P, Jenjaroen K, Roberts RA, Utaisincharoen P, Dunachie SJ, Brett PJ, Burtnick MN, Chantratita N. Immune response to recombinant Burkholderia pseudomallei FliC. PLoS One 2018; 13:e0198906. [PMID: 29902230 PMCID: PMC6002054 DOI: 10.1371/journal.pone.0198906] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Accepted: 05/29/2018] [Indexed: 11/22/2022] Open
Abstract
Burkholderia pseudomallei is a flagellated Gram-negative bacterium which is the causative agent of melioidosis. The disease poses a major public health problem in tropical regions and diabetes is a major risk factor. The high mortality rate of melioidosis is associated with severe sepsis which involves the overwhelming production of pro-inflammatory cytokines. Bacterial flagellar protein (flagellin) activates Toll-like receptor 5 (TLR5)-mediated innate immune signaling pathways and induces adaptive immune response. However, previous studies of TLR5 signaling in melioidosis have been performed using recombinant flagellin from Salmonella Typhimurium instead of B. pseudomallei. This study aimed to investigate human innate immune response and antibody response against a recombinant B. pseudomallei flagellin (rFliC). We prepared B. pseudomallei rFliC and used it to stimulate HEK-BlueTM-hTLR5 and THP1-DualTM cells to assess TLR5 activation. Subsequently, whole blood stimulation assays with rFliC were performed ex vivo. TLR5-flagellin interactions trigger activation of transcription factor NF-κB in HEK-BlueTM-hTLR5 cells. Pro-inflammatory cytokine (IL-1β, IL-6, and TNF-α) productions from whole blood in response to rFliC differed between fourteen healthy individuals. The levels of these cytokines changed in a dose and time-dependent manner. ELISA was used to determine rFliC-specific antibodies in serum samples from different groups of melioidosis patients and healthy subjects. IgG antibody to rFliC in melioidosis patients with diabetes were higher compared with non-diabetic patients. Our results show that B. pseudomallei flagellin is a potent immune stimulator and that the immune responses to rFliC are different among individuals. This may provide valuable insights toward the potential use of rFliC in vaccine development.
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Affiliation(s)
- Sirikamon Koosakulnirand
- Department of Microbiology, Faculty of Science, Mahidol University, Bangkok, Thailand
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Phornpun Phokrai
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Kemajittra Jenjaroen
- Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
| | - Rosemary A. Roberts
- Department of Microbiology and Immunology, University of South Alabama, Mobile, AL, United States of America
| | | | - Susanna J. Dunachie
- Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
- Center for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
| | - Paul J. Brett
- Department of Microbiology and Immunology, University of South Alabama, Mobile, AL, United States of America
| | - Mary N. Burtnick
- Department of Microbiology and Immunology, University of South Alabama, Mobile, AL, United States of America
| | - Narisara Chantratita
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
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11
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Vijayan A, Rumbo M, Carnoy C, Sirard JC. Compartmentalized Antimicrobial Defenses in Response to Flagellin. Trends Microbiol 2018; 26:423-435. [PMID: 29173868 DOI: 10.1016/j.tim.2017.10.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2017] [Revised: 10/20/2017] [Accepted: 10/27/2017] [Indexed: 11/19/2022]
Abstract
Motility is often a pathogenicity determinant of bacteria targeting mucosal tissues. Flagella constitute the machinery that propels bacteria into appropriate niches. Besides motility, the structural component, flagellin, which forms the flagella, targets Toll-like receptor 5 (TLR5) to activate innate immunity. The compartmentalization of flagellin-mediated immunity and the contribution of epithelial cells and dendritic cells in detecting flagellin within luminal and basal sides are highlighted here, respectively. While a direct stimulation of the epithelium mainly results in recruitment of immune cells and production of antimicrobial molecules, TLR5 engagement on parenchymal dendritic cells can contribute to the stimulation of innate lymphocytes such as type 3 innate lymphoid cells, as well as T helper cells. This review, therefore, illustrates how the innate and adaptive immunity to flagellin are differentially regulated by the epithelium and the dendritic cells in response to pathogens that either colonize or invade mucosa.
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Affiliation(s)
- Aneesh Vijayan
- Université Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR8204 - CIIL - Center for Infection and Immunity of Lille, F-59000 Lille, France
| | - Martin Rumbo
- Instituto de Estudios Inmunológicos y Fisiopatológicos - CONICET - National Universtity of La Plata, 1900 La Plata, Argentina
| | - Christophe Carnoy
- Université Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR8204 - CIIL - Center for Infection and Immunity of Lille, F-59000 Lille, France.
| | - Jean-Claude Sirard
- Université Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR8204 - CIIL - Center for Infection and Immunity of Lille, F-59000 Lille, France.
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12
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Abstract
Toll-like receptor 5 (TLR5) of mammals, birds, and reptiles detects bacterial flagellin and signals as a homodimeric complex. Structural studies using truncated TLR5b of zebrafish confirm the homodimeric TLR5-flagellin interaction. Here we provide evidence that zebrafish (Danio rerio) TLR5 unexpectedly signals as a heterodimer composed of the duplicated gene products drTLR5b and drTLR5a. Flagellin-induced signaling by the zebrafish TLR5 heterodimer increased in the presence of the TLR trafficking chaperone UNC93B1. Targeted exchange of drTLR5b and drTLR5a regions revealed that TLR5 activation needs a heterodimeric configuration of the receptor ectodomain and cytoplasmic domain, consistent with ligand-induced changes in receptor conformation. Structure-guided substitution of the presumed principal flagellin-binding site in human TLR5 with corresponding zebrafish TLR5 residues abrogated human TLR5 activation, indicating a species-specific TLR5-flagellin interaction. Our findings indicate that the duplicated TLR5 of zebrafish underwent subfunctionalization through concerted coevolution to form a unique heterodimeric flagellin receptor that operates fundamentally differently from TLR5 of other species.
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13
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Ajamian L, Melnychuk L, Jean-Pierre P, Zaharatos GJ. DNA Vaccine-Encoded Flagellin Can Be Used as an Adjuvant Scaffold to Augment HIV-1 gp41 Membrane Proximal External Region Immunogenicity. Viruses 2018; 10:E100. [PMID: 29495537 PMCID: PMC5869493 DOI: 10.3390/v10030100] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Revised: 02/22/2018] [Accepted: 02/23/2018] [Indexed: 02/07/2023] Open
Abstract
Flagellin's potential as a vaccine adjuvant has been increasingly explored over the last three decades. Monomeric flagellin proteins are the only known agonists of Toll-like receptor 5 (TLR5). This interaction evokes a pro-inflammatory state that impacts upon both innate and adaptive immunity. While pathogen associated molecular patterns (PAMPs) like flagellin have been used as stand-alone adjuvants that are co-delivered with antigen, some investigators have demonstrated a distinct advantage to incorporating antigen epitopes within the structure of flagellin itself. This approach has been particularly effective in enhancing humoral immune responses. We sought to use flagellin as both scaffold and adjuvant for HIV gp41 with the aim of eliciting antibodies to the membrane proximal external region (MPER). Accordingly, we devised a straightforward step-wise approach to select flagellin-antigen fusion proteins for gene-based vaccine development. Using plasmid DNA vector-based expression in mammalian cells, we demonstrate robust expression of codon-optimized full length and hypervariable region-deleted constructs of Salmonella enterica subsp. enterica serovar Typhi flagellin (FliC). An HIV gp41 derived sequence including the MPER (gp41607-683) was incorporated into various positions of these constructs and the expressed fusion proteins were screened for effective secretion, TLR5 agonist activity and adequate MPER antigenicity. We show that incorporation of gp41607-683 into a FliC-based scaffold significantly augments gp41607-683 immunogenicity in a TLR5 dependent manner and elicits modest MPER-specific humoral responses in a mouse model.
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Affiliation(s)
- Lara Ajamian
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, QC H3T 1E2, Canada.
- Division of Experimental Medicine, Department of Medicine, McGill University, Montréal, QC H4A 3J1, Canada.
| | - Luca Melnychuk
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, QC H3T 1E2, Canada.
- Division of Experimental Medicine, Department of Medicine, McGill University, Montréal, QC H4A 3J1, Canada.
| | - Patrick Jean-Pierre
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, QC H3T 1E2, Canada.
| | - Gerasimos J Zaharatos
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, QC H3T 1E2, Canada.
- Division of Infectious Disease, Department of Medicine & Division of Medical Microbiology, Department of Clinical Laboratory Medicine, Jewish General Hospital, Montréal, QC H3T 1E2, Canada.
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14
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Tahoun A, Jensen K, Corripio-Miyar Y, McAteer S, Smith DGE, McNeilly TN, Gally DL, Glass EJ. Host species adaptation of TLR5 signalling and flagellin recognition. Sci Rep 2017; 7:17677. [PMID: 29247203 PMCID: PMC5732158 DOI: 10.1038/s41598-017-17935-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 11/30/2017] [Indexed: 12/23/2022] Open
Abstract
Toll-like receptor 5 (TLR5) recognition of flagellin instigates inflammatory signalling. Significant sequence variation in TLR5 exists between animal species but its impact on activity is less well understood. Building on our previous research that bovine TLR5 (bTLR5) is functional, we compared human and bovine TLR5 activity and signalling in cognate cell lines. bTLR5 induced higher levels of CXCL8 when expressed in bovine cells and reciprocal results were found for human TLR5 (hTLR5) in human cells, indicative of host cell specificity in this response. Analysis of Toll/interleukin-1 receptor (TIR) sequences indicated that these differential responses involve cognate MyD88 recognition. siRNA knockdowns and inhibitor experiments demonstrated that there are some host differences in signalling. Although, PI3K activation is required for bTLR5 signalling, mutating bTLR5 F798 to hTLR5 Y798 within a putative PI3K motif resulted in a significantly reduced response. All ruminants have F798 in contrast to most other species, suggesting that TLR5 signalling has evolved differently in ruminants. Evolutionary divergence between bovine and human TLR5 was also apparent in relation to responses measured to diverse bacterial flagellins. Our results underscore the importance of species specific studies and how differences may alter efficacy of TLR-based vaccine adjuvants.
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Affiliation(s)
- Amin Tahoun
- Division of Immunity and Infection, The Roslin Institute and R(D)SVS, The University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK.,Faculty of Veterinary Medicine, Kafrelsheikh University, 33516, Kafr el-Sheikh, Egypt
| | - Kirsty Jensen
- Division of Immunity and Infection, The Roslin Institute and R(D)SVS, The University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
| | - Yolanda Corripio-Miyar
- Division of Immunity and Infection, The Roslin Institute and R(D)SVS, The University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK.,Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, EH26 OPZ, UK
| | - Sean McAteer
- Division of Immunity and Infection, The Roslin Institute and R(D)SVS, The University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
| | - David G E Smith
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, EH26 OPZ, UK.,University of Glasgow, Glasgow, G12 8TA, UK.,Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot Watt University, Edinburgh, EH14 4AS, UK
| | - Tom N McNeilly
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, EH26 OPZ, UK
| | - David L Gally
- Division of Immunity and Infection, The Roslin Institute and R(D)SVS, The University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
| | - Elizabeth J Glass
- Division of Immunity and Infection, The Roslin Institute and R(D)SVS, The University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK.
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15
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Forstnerič V, Ivičak-Kocjan K, Plaper T, Jerala R, Benčina M. The role of the C-terminal D0 domain of flagellin in activation of Toll like receptor 5. PLoS Pathog 2017; 13:e1006574. [PMID: 28827825 PMCID: PMC5578693 DOI: 10.1371/journal.ppat.1006574] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 08/31/2017] [Accepted: 08/09/2017] [Indexed: 11/19/2022] Open
Abstract
Flagellin is a wide-spread bacterial virulence factor sensed by the membrane-bound Toll-like receptor 5 (TLR5) and by the intracellular NAIP5/NLRC4 inflammasome receptor. TLR5 recognizes a conserved region within the D1 domain of flagellin, crucial for the interaction between subunits in the flagellum and for bacterial motility. While it is known that a deletion of the D0 domain of flagellin, which lines the interior of flagella, also completely abrogates activation of TLR5, its functional role remains unknown. Using a protein fusion strategy, we propose a role for the D0 domain in the stabilization of an active dimeric signaling complex of flagellin-TLR5 at a 2:2 stoichiometric ratio. Alanine-scanning mutagenesis of flagellin revealed a previously unidentified region of flagellin, the C-terminal D0 domain, to play a crucial role in TLR5 activation. Interestingly, we show that TLR5 recognizes the same hydrophobic motif of the D0 domain of flagellin as the intracellular NAIP5/NLRC4 inflammasome receptor. Further, we show that residues within the D0 domain play a previously unrecognized role in the evasion of TLR5 recognition by Helicobacter pylori. These findings demonstrate that TLR5 is able to simultaneously sense several spatially separated sites of flagellin that are essential for its functionality, hindering bacterial evasion of immune recognition. Our findings significantly contribute to the understanding of the mechanism of TLR5 activation, which plays an important role in host defense against several pathogens, but also in several diseases, such as Crohn’s disease, cystic fibrosis and rheumatoid arthritis. Receptors of the innate immune system typically recognize conserved microbial patterns, crucial for pathogen fitness and survival. Flagellin, the main structural protein of bacterial flagella, is recognized by two receptors of the innate immune system, the intracellular inflammasome receptor NAIP5/NLRC4 and the membrane-bound Toll-like receptor 5. Ligand-induced dimerization is a crucial step in Toll-like receptor 5 activation. A crystal structure of segments of the ligand-bound receptor revealed binding interfaces on the ligand and receptor, but failed to fully clarify the activation mechanism, since the D0 domain of flagellin, which is crucial for receptor activation, is missing in the structure. We propose a role for the D0 domain in receptor dimerization and pinpoint specific amino-acid residues within the D0 domain, which contribute to Toll-like receptor 5 activation. We show that Toll-like receptor 5 recognizes the same protein motif detected by the intracellular NAIP5/NLRC4 receptor. Our work represents an important advance in the understanding of the mechanism of activation of Toll-like receptor 5.
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Affiliation(s)
- Vida Forstnerič
- Department of Synthetic Biology and Immunology, National Institute of Chemistry, Ljubljana, Slovenia
| | - Karolina Ivičak-Kocjan
- Department of Synthetic Biology and Immunology, National Institute of Chemistry, Ljubljana, Slovenia
| | - Tjaša Plaper
- Department of Synthetic Biology and Immunology, National Institute of Chemistry, Ljubljana, Slovenia
| | - Roman Jerala
- Department of Synthetic Biology and Immunology, National Institute of Chemistry, Ljubljana, Slovenia
- Centre of Excellence EN-FIST, Ljubljana, Slovenia
- * E-mail: (RJ); (MB)
| | - Mojca Benčina
- Department of Synthetic Biology and Immunology, National Institute of Chemistry, Ljubljana, Slovenia
- * E-mail: (RJ); (MB)
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16
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Cao L, Zhang T, Zhu J, Li A, Zheng K, Zhang N, Su B, Xia W, Wu H, Li N, He Q. Polymorphism of TLR5 rs5744174 is associated with disease progression in Chinese patients with chronic HBV infection. APMIS 2017; 125:708-716. [PMID: 28543911 DOI: 10.1111/apm.12707] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 03/12/2017] [Indexed: 12/22/2022]
Abstract
Toll-like receptors (TLRs) play a crucial role in innate and adaptive immunity, protecting the host from viral pathogens. Studies have implicated that TLR5 is associated with various diseases such as autoimmune and inflammation related diseases. However, little is known about the relationship between TLR5 and hepatitis B virus (HBV) infection. We studied the effect of TLR5 gene polymorphisms on susceptibility to and disease progression of chronic hepatitis B (CHB) infection in Chinese. Blood samples were taken from 636 patients with CHB, HBV-related liver cirrhosis (LC) or hepatocellular carcinoma (HCC) and 273 controls. Polymorphisms of TLR5 (1775A>G rs2072493 and 1846T>C rs5744174) were analyzed by PCR-based sequencing. No difference in genotypic and allelic frequencies of TLR5 rs2072493 and rs5744174 was observed between patients and controls. Significant difference was found in frequency of TLR5 rs5744174 TT genotype between men with CHB and LC (p = 0.035). Frequency of TT genotype of TLR5 rs5744174 in patients positive for HBeAg was increased from 53.2% in patients with CHB to 74.1% in those with HCC (p = 0.024). Our results indicate that in Chinese genetic variation of TLR5 may be not a determinant of susceptibility to HBV-related diseases but may play a role in development of HBV-related severe liver diseases.
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Affiliation(s)
- Lina Cao
- Department of Medical Microbiology and Research Centre of Microbiome, Capital Medical University, Beijing, China
| | - Tong Zhang
- Department of Infectious Diseases, Beijing You'an Hospital, Capital Medical University, Beijing, China
| | - Junping Zhu
- Department of Medical Microbiology and Research Centre of Microbiome, Capital Medical University, Beijing, China
| | - Aixin Li
- Department of Infectious Diseases, Beijing You'an Hospital, Capital Medical University, Beijing, China
| | - Kai Zheng
- Department of Medical Microbiology and Research Centre of Microbiome, Capital Medical University, Beijing, China
| | - Nan Zhang
- Department of Medical Microbiology and Research Centre of Microbiome, Capital Medical University, Beijing, China
| | - Bin Su
- Department of Infectious Diseases, Beijing You'an Hospital, Capital Medical University, Beijing, China
| | - Wei Xia
- Department of Infectious Diseases, Beijing You'an Hospital, Capital Medical University, Beijing, China
| | - Hao Wu
- Department of Infectious Diseases, Beijing You'an Hospital, Capital Medical University, Beijing, China
| | - Ning Li
- Department of Infectious Diseases, Beijing You'an Hospital, Capital Medical University, Beijing, China
| | - Qiushui He
- Department of Medical Microbiology and Research Centre of Microbiome, Capital Medical University, Beijing, China.,Department of Medical Microbiology and Immunology, University of Turku, Turku, Finland
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17
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Xu Y, Wu D, Fan Y, Li P, Du H, Shi J, Wang D, Zhou X. Novel recombinant protein FlaA N/C increases tumor radiosensitivity via NF-κB signaling in murine breast cancer cells. Oncol Lett 2016; 12:2632-2640. [PMID: 27703525 PMCID: PMC5038907 DOI: 10.3892/ol.2016.4957] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 07/20/2016] [Indexed: 12/21/2022] Open
Abstract
The recombinant protein flagellin A (FlaA) N/C, derived from the flagellin protein of Legionella pneumophila, has been shown to increase the expression of cytoprotective cytokines, activate the nuclear factor-κB (NF-κB) signaling pathway, and increase the survival of mice following total body irradiation. Determi ning whether FlaA N/C has a sensitizing effect on tumor radiation or a direct tumoricidal effect is critical for its application as an effective radiation protection agent. The present study investigated the molecular mechanism underlying the tumor radiosensitivity of FlaA N/C. FlaA N/C was found to increase tumor apoptosis and autophagy, regulate the cell cycle and increase radiosensitivity in 4T1 tumor cells. Furthermore, FlaA N/C was found to promote radiosensitivity by activating NF-κB signaling. Finally, the present study analyzed FlaA N/C-enhanced radiosensitivity in animal models, and FlaA N/C was found to significantly prolong the survival period of mice after total body radiation. This indicates that FlaA N/C might be a novel radiation sensitizer in tumor radiation therapy.
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Affiliation(s)
- Ying Xu
- Clinical Laboratory, The First Affiliated Hospital of Chengdu Medical College, Chengdu, Sichuan 610041, P.R. China
| | - Dongming Wu
- Clinical Laboratory, The First Affiliated Hospital of Chengdu Medical College, Chengdu, Sichuan 610041, P.R. China
| | - Yuanchun Fan
- Clinical Laboratory, The First Affiliated Hospital of Chengdu Medical College, Chengdu, Sichuan 610041, P.R. China
| | - Peigeng Li
- Clinical Laboratory, The First Affiliated Hospital of Chengdu Medical College, Chengdu, Sichuan 610041, P.R. China
| | - Hongfei Du
- Clinical Laboratory, The First Affiliated Hospital of Chengdu Medical College, Chengdu, Sichuan 610041, P.R. China
| | - Jiao Shi
- Clinical Laboratory, The First Affiliated Hospital of Chengdu Medical College, Chengdu, Sichuan 610041, P.R. China
| | - Dan Wang
- Clinical Laboratory, The First Affiliated Hospital of Chengdu Medical College, Chengdu, Sichuan 610041, P.R. China
| | - Xiaoping Zhou
- Clinical Laboratory, The First Affiliated Hospital of Chengdu Medical College, Chengdu, Sichuan 610041, P.R. China
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