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Taylor C, Belin E, Brodbelt D, Klaasen HLBM, Catchpole B. Exploration of the potential utility of the luciferase immunoprecipitation system (LIPS) assay for the detection of anti-leptospira antibodies in dogs. Vet Immunol Immunopathol 2023; 264:110661. [PMID: 37827091 DOI: 10.1016/j.vetimm.2023.110661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 10/04/2023] [Indexed: 10/14/2023]
Abstract
Canine leptospirosis represents a diagnostic challenge to veterinarians, due to the variability in presenting clinical signs and interpretation of serology test results in dogs that have been vaccinated previously. None of the commercially available serological assays, including the microscopic agglutination test (MAT), have been verified to be capable of differentiating infected from vaccinated animals (DIVA). Recent work identified that half of primary practice attending dogs were up to date with their leptospirosis vaccination and would be expected to have circulating anti-leptospira antibodies (Taylor et al., 2022), indicating that this is a relevant issue for suspected leptospirosis cases in dogs in the UK. This study aimed to explore the utility of three leptospiral outer membrane proteins (OMPs: LipL32, LipL21 and LipL41) as potential DIVA targets in the luciferase immunoprecipitation system (LIPS) assay. N and C terminal nanoluciferase tagged recombinant proteins were generated for each OMP. Differences in reactivity between serum samples from MAT positive dogs (n = 29) and paired samples (n = 6 dogs) taken pre and 21 days post leptospirosis vaccination were assessed against these six constructs. Reactivity was greater towards the N terminal than the C terminal recombinant proteins for all three OMPs. None of the constructs appeared to demonstrate DIVA capability, although two (pNLF1-N-FLAG/LipL32 and pNLF1-N-FLAG/LipL21) were able to detect vaccine seroconversion. The findings of this work suggest that these particular OMP targets do not offer DIVA ability, however LipL32 and LipL21 may be suitable for use in immunoassays for vaccine trials or for detection of infections in humans, where there is no requirement for DIVA capability.
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Affiliation(s)
- C Taylor
- Royal Veterinary College, Hawkshead Lane, Hatfield, Hertfordshire, United Kingdom.
| | - E Belin
- Royal Veterinary College, Hawkshead Lane, Hatfield, Hertfordshire, United Kingdom
| | - D Brodbelt
- Royal Veterinary College, Hawkshead Lane, Hatfield, Hertfordshire, United Kingdom
| | - H L B M Klaasen
- Global Companion Animals Research and Development, Merck Sharp and Dohme Animal Health, Boxmeer, the Netherlands
| | - B Catchpole
- Royal Veterinary College, Hawkshead Lane, Hatfield, Hertfordshire, United Kingdom
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Behera SK, Sabarinath T, Mishra PKK, Deneke Y, Kumar A, ChandraSekar S, Senthilkumar K, Verma M, Ganesh B, Gurav A, Hota A. Immunoinformatic Study of Recombinant LigA/BCon1-5 Antigen and Evaluation of Its Diagnostic Potential in Primary and Secondary Binding Tests for Serodiagnosis of Porcine Leptospirosis. Pathogens 2021; 10:1082. [PMID: 34578116 PMCID: PMC8466556 DOI: 10.3390/pathogens10091082] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 08/05/2021] [Accepted: 08/16/2021] [Indexed: 11/20/2022] Open
Abstract
Leptospirosis is responsible for hampering the productivity of swine husbandry worldwide. The aim of this study was to assess the efficacy of bioinformatics tools in predicting the three-dimensional structure and immunogenicity of recombinant LigBCon1-5 (rLigBCon1-5) antigen. A battery of bioinformatics tools such as I-TASSER, ProSA and SAVES v6.0 were used for the prediction and assessment of the predicted structure of rLigBCon1-5 antigen. Bepipred-2.0, DiscoTope v2.0 and ElliPro servers were used to predict linear and conformational epitopes while T-cell epitopes were predicted using NetMHCpan 4.1 and IEDB recommended 2.22 method for MHC Class I and II peptides respectively. The results obtained using various in silico methods were then compared with wet lab experiments comprising of both primary (IgG Dot ELISA Dipstick test) and secondary-binding assays (Latex Agglutination Test [LAT]) to screen 1153 porcine serum samples. The three-dimensional structure of rLigA/BCon1-5 protein as predicted by I-TASSER was found to be reliable by Ramachandran Plot and ProSA. The ElliPro server suggested 10 and three potential linear and conformational B-cell-epitopes, respectively, on the peptide backbone of the rLigA/BCon1-5 protein. The DiscoTope prediction server suggested 47 amino acid residues to be part of B-cell antigen. Ten of the most efficient peptides for MHC-I and II grooves were predicted by NetMHCpan 4.1 and IEDB recommended 2.22 method, respectively. Of these, three peptides can serve dual functions as it can fit both MHC I and II grooves, thereby eliciting both humoral-and cell-mediated immune responses. The prediction of these computational approaches proved to be reliable since rLigBCon1-5 antigen-based IgG Dot ELISA Dipstick test and LAT gave results in concordance to gold standard test, the Microscopic Agglutination Test (MAT), for serodiagnosis of leptospirosis. Both the IgG Dot ELISA Dipstick test and LAT were serodiagnostic assays ideally suited for peripheral level of animal health care system as "point of care" tests for the detection of porcine leptospirosis.
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Affiliation(s)
- Sujit Kumar Behera
- Department of Epidemiology & Public Health, Central University of Tamil Nadu, Tiruvarur 610001, India;
| | - Thankappan Sabarinath
- Clinical Bacteriological Laboratory, Indian Council of Agricultural Research—Indian Veterinary Research Institute, Mukteshwar, Nainital 263138, India
| | - Prasanta Kumar K. Mishra
- Faculty of Veterinary and Animal Sciences, Rajiv Gandhi South Campus, Banaras Hindu University, Mirzapur 231001, India;
| | - Yosef Deneke
- School of Veterinary Medicine, Jimma University, Jimma 378, Ethiopia;
| | - Ashok Kumar
- Krishi Bhawan, Indian Council of Agricultural Research, New Delhi 110001, India;
| | - Shanmugam ChandraSekar
- Biochemistry Laboratory, Indian Council of Agricultural Research—Indian Veterinary Research Institute, Mukteshwar, Nainital 263138, India;
| | - Kuppusamy Senthilkumar
- Zoonoses Research Laboratory, Tamil Nadu Veterinary and Animal Sciences University, Chennai 600051, India;
| | - MedRam Verma
- Livestock Economics & Statistics Division, Indian Council of Agricultural Research—Indian Veterinary Research Institute, Bareilly 243122, India;
| | | | - Amol Gurav
- Temperate Animal Husbandry Division, ICAR—Indian Veterinary Research Institute (IVRI), Mukteshwar, Nainital 263138, India;
| | - Abhishek Hota
- Department of Animal Science, Centurion University of Technology and Management, Paralakhemundi 761211, India;
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Mathesh K, Thankappan S, Deneke Y, Vamadevan B, Siddappa CM, Sharma AK, Selvaraj I, Sha A, Kumar A. A multipronged approach for the detection of leptospirosis in captive sloth bears (Melursus ursinus) in Agra and Bannerghatta sloth bear rescue centers in India. J Vet Med Sci 2021; 83:1059-1067. [PMID: 33994428 PMCID: PMC8349803 DOI: 10.1292/jvms.21-0082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Leptospirosis is an exacerbating factor responsible for the drastic decline of sloth bear population in India. In this study, a multipronged approach based on
antigen detection using Polymerase Chain Reaction (PCR) employing G1/G2 and LigBF/LigBR primers, antibody detection using Microscopic Agglutination Test (MAT)
and recombinant LigBCon1-5 antigen based Latex Agglutination Test (rLigBCon1-5 LAT), serum biochemistry using hepatic (serum glutamate oxalo acetic transaminase
(SGOT) and serum glutamate pyruvic transaminase (SGPT) and renal biomarkers (blood urea nitrogen (BUN) and Creatinine) and gross/histopathological evidence in
liver and kidneys were employed to investigate leptospirosis in captive sloth bears. A total of 133 serum samples collected from Agra (n=113) and Bannerghatta
(n=20) sloth bear rescue centers were screened using MAT and rLigBCon1-5 LAT. A total of 87 and 78 sera tested positive by MAT and LAT respectively. Pyrogenes
was the leading serovar obtained using MAT followed by Icterohaemorrhagiae, Javanica, Grippotyphosa, Canicola and Tarassovi. The relative sensitivity,
specificity and accuracy of rLigBCon1-5 LAT in comparison to MAT were 89.66%, 100% and 93.23% respectively. PCR performed on hepatic and renal tissues showed
amplicon of 285 and 219 base pairs for G1/G2 and LigBF/LigBR primers respectively. Gross evidence (icteric liver, severely engorged hepatic sinusoids, congested
kidneys with necrotic white spots on sub capsular surface), histopathology (severe hepatic degeneration and tubulointerstitial nephritis) and elevated
hepatic/renal biomarkers were suggestive of leptospirosis. This study suggests that rLigBCon1-5 LAT can be employed as a pen-side test for detecting
leptospirosis in sloth bears.
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Affiliation(s)
- Karikalan Mathesh
- Center for Wildlife, ICAR-IVRI, Izzatnagar, Uttar Pradesh 243122, India
| | - Sabarinath Thankappan
- Clinical Bacteriological Laboratory, ICAR-IVRI, Mukteshwar, Uttarakhand 263138, India
| | - Yosef Deneke
- School of Veterinary Medicine, Jimma University, P.O. Box 378, Ethiopia
| | - Beena Vamadevan
- Veterinary Pathology Division, ICAR-IVRI, Izzatnagar, Uttar Pradesh 243122, India
| | | | - Anil Kumar Sharma
- Center for Wildlife, ICAR-IVRI, Izzatnagar, Uttar Pradesh 243122, India
| | - Ilayaraja Selvaraj
- Agra Bear Rescue Center, Wildlife SOS, Keetham, Agra, Uttar Pradesh 283101, India
| | - Arun Sha
- Bannerghatta Bear Rescue Center, Wildlife SOS, Bengaluru 560083, India
| | - Ashok Kumar
- Krishi Bhawan, ICAR, New Delhi 110001, India
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Samrot AV, Sean TC, Bhavya KS, Sahithya CS, Chan-drasekaran S, Palanisamy R, Robinson ER, Subbiah SK, Mok PL. Leptospiral Infection, Pathogenesis and Its Diagnosis-A Review. Pathogens 2021; 10:pathogens10020145. [PMID: 33535649 PMCID: PMC7912936 DOI: 10.3390/pathogens10020145] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 12/05/2020] [Accepted: 12/09/2020] [Indexed: 12/22/2022] Open
Abstract
Leptospirosis is a perplexing conundrum for many. In the existing literature, the pathophysiological mechanisms pertaining to leptospirosis is still not understood in full. Considered as a neglected tropical zoonotic disease, leptospirosis is culminating as a serious problem worldwide, seemingly existing as co-infections with various other unrelated diseases, including dengue and malaria. Misdiagnosis is also common as non-specific symptoms are documented extensively in the literature. This can easily lead to death, as the severe form of leptospirosis (Weil's disease) manifests as a complex of systemic complications, especially renal failure. The virulence of Leptospira sp. is usually attributed to the outer membrane proteins, including LipL32. With an armament of virulence factors at their disposal, their ability to easily adhere, invade and replicate within cells calls for a swift refinement in research progress to establish their exact pathophysiological framework. As an effort to reconstitute the current knowledge on leptospirosis, the basis of leptospiral infection, including its risk factors, classification, morphology, transmission, pathogenesis, co-infections and clinical manifestations are highlighted in this review. The various diagnostic techniques are also outlined with emphasis on their respective pros and cons.
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Affiliation(s)
- Antony V. Samrot
- School of Bioscience, Faculty of Medicine, Bioscience and Nursing, MAHSA University, Jenjarom, Selangor 42610, Malaysia;
- Correspondence: (A.V.S.); (P.L.M.)
| | - Tan Chuan Sean
- School of Bioscience, Faculty of Medicine, Bioscience and Nursing, MAHSA University, Jenjarom, Selangor 42610, Malaysia;
| | - Karanam Sai Bhavya
- Department of Biotechnology, School of Bio and Chemical Engineering, Sathyabama Institute of Science and Technology, Jeppiaar Nagar, Chennai, Tamil Nadu 627 011, India; (K.S.B.); (C.S.S.); (S.C.); (R.P.)
| | - Chamarthy Sai Sahithya
- Department of Biotechnology, School of Bio and Chemical Engineering, Sathyabama Institute of Science and Technology, Jeppiaar Nagar, Chennai, Tamil Nadu 627 011, India; (K.S.B.); (C.S.S.); (S.C.); (R.P.)
| | - SaiPriya Chan-drasekaran
- Department of Biotechnology, School of Bio and Chemical Engineering, Sathyabama Institute of Science and Technology, Jeppiaar Nagar, Chennai, Tamil Nadu 627 011, India; (K.S.B.); (C.S.S.); (S.C.); (R.P.)
| | - Raji Palanisamy
- Department of Biotechnology, School of Bio and Chemical Engineering, Sathyabama Institute of Science and Technology, Jeppiaar Nagar, Chennai, Tamil Nadu 627 011, India; (K.S.B.); (C.S.S.); (S.C.); (R.P.)
| | - Emilin Renitta Robinson
- Department of Food Processing Technology, Karunya Institute of Technology and Science, Coimbatore, Tamil Nadu 641 114, India;
| | - Suresh Kumar Subbiah
- Department of Medical Microbiology and Parasitology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, UPM Serdang, Selangor 43400, Malaysia;
- Department of Biotechnology, Bharath Institute of Higher Education and Research (BIHER), Selaiyur, Tamil Nadu 600 073, India
- Genetics and Regenerative Medicine Research Centre, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, UPM Serdang, Selangor 43400, Malaysia
| | - Pooi Ling Mok
- Department of Biotechnology, Bharath Institute of Higher Education and Research (BIHER), Selaiyur, Tamil Nadu 600 073, India
- Genetics and Regenerative Medicine Research Centre, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, UPM Serdang, Selangor 43400, Malaysia
- Department of Biomedical Science, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, UPM Serdang, Selangor 43400, Malaysia
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Jouf University, Sakaka P.O. Box 2014, Aljouf Province, Saudi Arabia
- Correspondence: (A.V.S.); (P.L.M.)
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Teixeira AF, Fernandes LG, Cavenague MF, Takahashi MB, Santos JC, Passalia FJ, Daroz BB, Kochi LT, Vieira ML, Nascimento AL. Adjuvanted leptospiral vaccines: Challenges and future development of new leptospirosis vaccines. Vaccine 2019; 37:3961-3973. [DOI: 10.1016/j.vaccine.2019.05.087] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 04/16/2019] [Accepted: 05/21/2019] [Indexed: 12/26/2022]
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6
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Ptak CP, Akif M, Hsieh C, Devarajan A, He P, Xu Y, Oswald RE, Chang Y. Comparative screening of recombinant antigen thermostability for improved leptospirosis vaccine design. Biotechnol Bioeng 2018; 116:260-271. [DOI: 10.1002/bit.26864] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 10/29/2018] [Accepted: 11/07/2018] [Indexed: 12/29/2022]
Affiliation(s)
- Christopher P. Ptak
- Department of Population Medicine and Diagnostic SciencesCollege of Veterinary Medicine, Cornell UniversityIthaca New York
- Department of Molecular MedicineCollege of Veterinary Medicine, Cornell UniversityIthaca New York
| | - Mohd. Akif
- Department of Population Medicine and Diagnostic SciencesCollege of Veterinary Medicine, Cornell UniversityIthaca New York
- Department of BiochemistryUniversity of HyderabadHyderabad India
| | - Ching‐Lin Hsieh
- Department of Population Medicine and Diagnostic SciencesCollege of Veterinary Medicine, Cornell UniversityIthaca New York
| | - Alex Devarajan
- Department of Molecular MedicineCollege of Veterinary Medicine, Cornell UniversityIthaca New York
| | - Ping He
- Department of Microbiology and ImmunologyInstitutes of Medical Science, Shanghai Jiao Tong University School of MedicineShanghai China
| | - Yinghua Xu
- Key Laboratory of the Ministry of Health for Research on Quality and Standardization of Biotech Products, National Institutes for Food and Drug ControlBeijing China
| | - Robert E. Oswald
- Department of Molecular MedicineCollege of Veterinary Medicine, Cornell UniversityIthaca New York
| | - Yung‐Fu Chang
- Department of Population Medicine and Diagnostic SciencesCollege of Veterinary Medicine, Cornell UniversityIthaca New York
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7
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Lessa-Aquino C, Lindow JC, Randall A, Wunder E, Pablo J, Nakajima R, Jasinskas A, Cruz JS, Damião AO, Nery N, Ribeiro GS, Costa F, Hagan JE, Reis MG, Ko AI, Medeiros MA, Felgner PL. Distinct antibody responses of patients with mild and severe leptospirosis determined by whole proteome microarray analysis. PLoS Negl Trop Dis 2017; 11:e0005349. [PMID: 28141801 PMCID: PMC5302828 DOI: 10.1371/journal.pntd.0005349] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 02/10/2017] [Accepted: 01/22/2017] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Leptospirosis is an important zoonotic disease worldwide. Humans usually present a mild non-specific febrile illness, but a proportion of them develop more severe outcomes, such as multi-organ failure, lung hemorrhage and death. Such complications are thought to depend on several factors, including the host immunity. Protective immunity is associated with humoral immune response, but little is known about the immune response mounted during naturally-acquired Leptospira infection. METHODS AND PRINCIPAL FINDINGS Here, we used protein microarray chip to profile the antibody responses of patients with severe and mild leptospirosis against the complete Leptospira interrogans serovar Copenhageni predicted ORFeome. We discovered a limited number of immunodominant antigens, with 36 antigens specific to patients, of which 11 were potential serodiagnostic antigens, identified at acute phase, and 33 were potential subunit vaccine targets, detected after recovery. Moreover, we found distinct antibody profiles in patients with different clinical outcomes: in the severe group, overall IgM responses do not change and IgG responses increase over time, while both IgM and IgG responses remain stable in the mild patient group. Analyses of individual patients' responses showed that >74% of patients in the severe group had significant IgG increases over time compared to 29% of patients in the mild group. Additionally, 90% of IgM responses did not change over time in the mild group, compared to ~51% in the severe group. CONCLUSIONS In the present study, we detected antibody profiles associated with disease severity and speculate that patients with mild disease were protected from severe outcomes due to pre-existing antibodies, while patients with severe leptospirosis demonstrated an antibody profile typical of first exposure. Our findings represent a significant advance in the understanding of the humoral immune response to Leptospira infection, and we have identified new targets for the development of subunit vaccines and diagnostic tests.
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Affiliation(s)
| | - Janet C. Lindow
- Fiocruz, Gonçalo Moniz Research Institute, Brazilian Ministry of Health, Salvador, BA, Brazil
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, United States of America
| | - Arlo Randall
- Antigen Discovery Inc, Irvine, CA, United States of America
| | - Elsio Wunder
- Fiocruz, Gonçalo Moniz Research Institute, Brazilian Ministry of Health, Salvador, BA, Brazil
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, United States of America
| | - Jozelyn Pablo
- Department of Medicine, Division of Infectious Disease, University of California Irvine, Irvine, California, United States of America
| | - Rie Nakajima
- Department of Medicine, Division of Infectious Disease, University of California Irvine, Irvine, California, United States of America
| | - Algis Jasinskas
- Department of Medicine, Division of Infectious Disease, University of California Irvine, Irvine, California, United States of America
| | - Jaqueline S. Cruz
- Fiocruz, Gonçalo Moniz Research Institute, Brazilian Ministry of Health, Salvador, BA, Brazil
| | - Alcineia O. Damião
- Fiocruz, Gonçalo Moniz Research Institute, Brazilian Ministry of Health, Salvador, BA, Brazil
| | - Nívison Nery
- Fiocruz, Gonçalo Moniz Research Institute, Brazilian Ministry of Health, Salvador, BA, Brazil
| | - Guilherme S. Ribeiro
- Institute of Collective Health, Federal University of Bahia, Salvador, BA, Brazil
| | - Federico Costa
- Fiocruz, Gonçalo Moniz Research Institute, Brazilian Ministry of Health, Salvador, BA, Brazil
- Institute of Collective Health, Federal University of Bahia, Salvador, BA, Brazil
| | - José E. Hagan
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, United States of America
| | - Mitermayer Galvão Reis
- Fiocruz, Gonçalo Moniz Research Institute, Brazilian Ministry of Health, Salvador, BA, Brazil
| | - Albert I. Ko
- Fiocruz, Gonçalo Moniz Research Institute, Brazilian Ministry of Health, Salvador, BA, Brazil
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, United States of America
| | | | - Philip L. Felgner
- Department of Medicine, Division of Infectious Disease, University of California Irvine, Irvine, California, United States of America
- * E-mail:
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Whole genome sequencing revealed host adaptation-focused genomic plasticity of pathogenic Leptospira. Sci Rep 2016; 6:20020. [PMID: 26833181 PMCID: PMC4735792 DOI: 10.1038/srep20020] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 12/09/2015] [Indexed: 12/31/2022] Open
Abstract
Leptospirosis, caused by pathogenic Leptospira spp., has recently been recognized as an emerging infectious disease worldwide. Despite its severity and global importance, knowledge about the molecular pathogenesis and virulence evolution of Leptospira spp. remains limited. Here we sequenced and analyzed 102 isolates representing global sources. A high genomic variability were observed among different Leptospira species, which was attributed to massive gene gain and loss events allowing for adaptation to specific niche conditions and changing host environments. Horizontal gene transfer and gene duplication allowed the stepwise acquisition of virulence factors in pathogenic Leptospira evolved from a recent common ancestor. More importantly, the abundant expansion of specific virulence-related protein families, such as metalloproteases-associated paralogs, were exclusively identified in pathogenic species, reflecting the importance of these protein families in the pathogenesis of leptospirosis. Our observations also indicated that positive selection played a crucial role on this bacteria adaptation to hosts. These novel findings may lead to greater understanding of the global diversity and virulence evolution of Leptospira spp.
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In Vivo-Expressed Proteins of Virulent Leptospira interrogans Serovar Autumnalis N2 Elicit Strong IgM Responses of Value in Conclusive Diagnosis. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2015; 23:65-72. [PMID: 26607308 DOI: 10.1128/cvi.00509-15] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 11/11/2015] [Indexed: 11/20/2022]
Abstract
Leptospirosis is a serious zoonosis that is underdiagnosed because of limited access to laboratory facilities in Southeast Asia, Central and South America, and Oceania. Timely diagnosis of locally distributed serovars of high virulence is crucial for successful care and outbreak management. Using pooled patient sera, an expression gene library of a virulent Leptospira interrogans serovar Autumnalis strain N2 isolated in South India was screened. The identified genes were characterized, and the purified recombinant proteins were used as antigens in IgM enzyme-linked immunosorbent assay (ELISA) either singly or in combination. Sera (n = 118) from cases of acute leptospirosis along with sera (n = 58) from healthy subjects were tested for reactivity with the identified proteins in an ELISA designed to detect specific IgM responses. We have identified nine immunoreactive proteins, ArgC, RecA, GlpF, FliD, TrmD, RplS, RnhB, Lp28.6, and Lrr44.9, which were found to be highly conserved among pathogenic leptospires. Apparently, the proteins ArgC, RecA, GlpF, FliD, TrmD, and Lrr44.9 are expressed during natural infection of the host and undetectable in in vitro cultures. Among all the recombinant proteins used as antigens in IgM ELISA, ArgC had the highest sensitivity and specificity, 89.8% and 95.5%, respectively, for the conclusive diagnosis of leptospirosis. The use of ArgC and RecA in combination for IgM ELISA increased the sensitivity and specificity to 95.7% and 94.9%, respectively. ArgC and RecA thus elicited specific IgM responses and were therefore effective in laboratory confirmation of Leptospira infection.
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10
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Mei S, Zhang J, Zhang X, Tu X. Solution structure of leptospiral LigA4 Big domain. Biochem Biophys Res Commun 2015; 467:288-92. [DOI: 10.1016/j.bbrc.2015.09.170] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 09/30/2015] [Indexed: 10/23/2022]
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11
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Breda LCD, Hsieh CL, Castiblanco Valencia MM, da Silva LB, Barbosa AS, Blom AM, Yung-Fu C, Isaac L. Fine Mapping of the Interaction between C4b-Binding Protein and Outer Membrane Proteins LigA and LigB of Pathogenic Leptospira interrogans. PLoS Negl Trop Dis 2015; 9:e0004192. [PMID: 26517116 PMCID: PMC4627802 DOI: 10.1371/journal.pntd.0004192] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 10/05/2015] [Indexed: 12/20/2022] Open
Abstract
The complement system consists of more than 40 proteins that participate in the inflammatory response and in pathogen killing. Complement inhibitors are necessary to avoid the excessive consumption and activation of this system on host cells. Leptospirosis is a worldwide zoonosis caused by spirochetes from the genus Leptospira. Pathogenic leptospires are able to escape from complement activation by binding to host complement inhibitors Factor H [FH] and C4b-binding protein (C4BP) while non-pathogenic leptospires are rapidly killed in the presence of fresh serum. In this study, we demonstrate that complement control protein domains (CCP) 7 and 8 of C4BP α-chain interact with the outer membrane proteins LcpA, LigA and LigB from the pathogenic leptospire L. interrogans. The interaction between C4BP and LcpA, LigA and LigB is sensitive to ionic strength and inhibited by heparin. We fine mapped the LigA and LigB domains involved in its binding to C4BP and heparin and found that both interactions are mediated through the bacterial immunoglobulin-like (Big) domains 7 and 8 (LigA7-8 and LigB7-8) of both LigA and LigB and also through LigB9-10. Therefore, C4BP and heparin may share the same binding sites on Lig proteins.
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Affiliation(s)
- Leandro C. D. Breda
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Ching-Lin Hsieh
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | | | | | | | - Anna M. Blom
- Department of Translational Medicine, Division of Medical Protein Chemistry, Lund University, Malmo, Sweden
| | - Chang Yung-Fu
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | - Lourdes Isaac
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
- * E-mail:
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12
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Liu M, Chen S. A novel adhesive factor contributing to the virulence of Vibrio parahaemolyticus. Sci Rep 2015; 5:14449. [PMID: 26399174 PMCID: PMC4585867 DOI: 10.1038/srep14449] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 06/26/2015] [Indexed: 11/25/2022] Open
Abstract
Bacterial adhesins play a pivotal role in the tight bacteria-host cells attachment to initiate the downstream processes and bacterial infection of hosts. In this study, we identified a novel adhesin, VpadF in V. parahaemolyticus. Deletion of VpadF in V. parahaemolyticus markedly impaired its attachment and cytotoxicity to epithelial cells, as well as attenuated the virulence in murine model. Biochemical studies revealed that VpadF recognized both fibronectin and fibrinogen. The binding of VpadF to these two host receptors was mainly dependent on the its fifth bacterial immunoglobulin-like group domain and its C-terminal tail. Our finding suggested that VpadF is a major virulence factor of V. parahaemolyticus and a potential good candidate for V. parahaemolyticus infection control for both vaccine development and drug target.
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Affiliation(s)
- Ming Liu
- Shenzhen Key Lab for Food Biological Safety Control, Food Safety and Technology Research Center, Hong Kong PolyU Shenzhen Research Institute, Shenzhen, China.,State Key Laboratory of Chirosciences, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China
| | - Sheng Chen
- Shenzhen Key Lab for Food Biological Safety Control, Food Safety and Technology Research Center, Hong Kong PolyU Shenzhen Research Institute, Shenzhen, China.,State Key Laboratory of Chirosciences, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China
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Nagalingam M, Thirumalesh SRA, Kalleshamurthy T, Niharika N, Balamurugan V, Shome R, Sengupta PP, Shome BR, Prabhudas K, Rahman H. Comparative evaluation of recombinant LigB protein and heat-killed antigen-based latex agglutination test with microscopic agglutination test for diagnosis of bovine leptospirosis. Trop Anim Health Prod 2015; 47:1329-35. [DOI: 10.1007/s11250-015-0867-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 06/03/2015] [Indexed: 11/29/2022]
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14
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Ye C, Yan W, Xiang H, He H, Yang M, Ijaz M, Useh N, Hsieh CL, McDonough PL, McDonough SP, Mohamed H, Yang Z, Chang YF. Recombinant antigens rLipL21, rLoa22, rLipL32 and rLigACon4-8 for serological diagnosis of leptospirosis by enzyme-linked immunosorbent assays in dogs. PLoS One 2014; 9:e111367. [PMID: 25526513 PMCID: PMC4272274 DOI: 10.1371/journal.pone.0111367] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 09/30/2014] [Indexed: 01/07/2023] Open
Abstract
Animal leptospirosis is one of the most common zoonotic diseases in the United States and around the world. In a previous study, we applied four recombinant antigens, rLipL21, rLoa22, rLipL32 and rLigACon4-8 of Leptospira interrogans (L. interrogans) for the serological diagnosis of equine leptospirosis (Ye et al, Serodiagnosis of equine leptospirosis by ELISA using four recombinant protein markers, Clin. Vaccine. Immunol. 21:478–483). In this study, the same four recombinant antigens were evaluated for their potential to diagnose canine leptospirosis by ELISA. A total of 305 canine sera that were Leptospira microscopic agglutination test (MAT)-negative (n = 102) and MAT-positive (n = 203) to 5 serovars (Pomona, Grippotyphosa, Icterohaemorrhagiae, Canicola and Hardjo) were tested. When individual recombinant antigens were used, the sensitivity and specificity of ELISA were 97.5% and 84.3% for rLigACon4-8; 89.7% and 81.4% for rLoa22; 92.6% and 84.3% for rLipL32 and 99.5% and 84.3% for rLipL21, respectively compared to the MAT. The sensitivity and specificity of ELISA were, 92.6% and 91.2% for rLigACon4-8 and rLipL32, 97.5% and 84.3% for rLigACon4-8 and rLipL21, 89.7% and 87.3% for rLigACon4-8 and rLoa22, 89.7% and 87.3% to rLipL21 and rLoa22, 92.6% and 91.2% for rLipL21 and rLipL32 and 89.2% and 94.1% for rLoa22 and rLipL32 when one of the two antigens was test positive. The use of all four antigens in the ELISA assay was found to be sensitive and specific, easy to perform, and agreed with the results of the standard Leptospira Microscopic Agglutination test (MAT) for the diagnosis of canine leptospirosis.
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Affiliation(s)
- Cuilian Ye
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
- School of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing, China
- Department of Pathogenic Biology, School of Basic Medical Sciences, Chongqing Medical University, Chongqing, China
| | - Weiwei Yan
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | - Hua Xiang
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
- Veterinary Institute, Guangdong Academy of Agriculture Sciences, Guangzhou, China
| | - Hongxuan He
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
- Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Maosheng Yang
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
- Guizhou Institute of Animal Husbandry and Veterinary Medicine, Guizhou Academy of Agriculture Sciences, Longdongbao, Guiyang, China
| | - Muhammad Ijaz
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | - Nicodemus Useh
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | - Ching-Lin Hsieh
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | - Patrick L. McDonough
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | - Sean P. McDonough
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | - Hussni Mohamed
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | - Zhibang Yang
- Department of Pathogenic Biology, School of Basic Medical Sciences, Chongqing Medical University, Chongqing, China
| | - Yung-Fu Chang
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
- * E-mail:
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15
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Mei S, Zhang J, Zhang X, Tu X. Solution structure of a bacterial immunoglobulin-like domain of the outer membrane protein (LigB) from Leptospira. Proteins 2014; 83:195-200. [PMID: 25393078 DOI: 10.1002/prot.24723] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 11/04/2014] [Accepted: 11/06/2014] [Indexed: 11/06/2022]
Abstract
Leptospiral immunoglobulin-like (Lig) proteins are surface proteins expressed in pathogenic strains of Leptospira. LigB, an outer membrane protein containing tandem repeats of bacterial Ig-like (Big) domains and a no-repeat tail, has been identified as a virulence factor involved in adhesion of pathogenic Leptospira interrogans to host cells. A Big domain of LigB, LigBCen2R, was reported previously to bind the GBD domain of fibronectin, suggesting its important role in leptospiral infections. In this study, we determined the solution structure of LigBCen2R by nuclear magnetic resonance (NMR) spectroscopy. LigBCen2R adopts a canonical immunoglobulin-like fold which is comprised of a beta-sandwich of ten strands in three sheets. We indicated that LigBCen2R is able to bind to Ca(2+) with a high affinity by isothermal titration calorimetry assay. NMR perturbation experiment identified a number of residues responsible for Ca(2+) binding. Structural comparison of it with other Big domains demonstrates that they share a similar fold pattern, but vary in some structural characters. Since Lig proteins play a vital role in the infection to host cells, our study will contribute a structural basis to understand the interactions between Leptospira and host cells.
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Affiliation(s)
- Song Mei
- Hefei National Laboratory for Physical Sciences at Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, 230026, People's Republic of China
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16
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Ptak CP, Hsieh CL, Lin YP, Maltsev AS, Raman R, Sharma Y, Oswald RE, Chang YF. NMR solution structure of the terminal immunoglobulin-like domain from the leptospira host-interacting outer membrane protein, LigB. Biochemistry 2014; 53:5249-60. [PMID: 25068811 PMCID: PMC4139157 DOI: 10.1021/bi500669u] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A number of surface proteins specific to pathogenic strains of Leptospira have been identified. The Lig protein family has shown promise as a marker in typing leptospiral isolates for pathogenesis and as an antigen in vaccines. We used NMR spectroscopy to solve the solution structure of the twelfth immunoglobulin-like (Ig-like) repeat domain from LigB (LigB-12). The fold is similar to that of other bacterial Ig-like domains and comprised mainly of β-strands that form a β-sandwich based on a Greek-key folding arrangement. Based on sequence analysis and conservation of structurally important residues, homology models for the other LigB Ig-like domains were generated. The set of LigB models illustrates the electrostatic differences between the domains as well as the possible interactions between neighboring domains. Understanding the structure of the extracellular portion of LigB and related proteins is important for developing diagnostic methods and new therapeutics directed toward leptospirosis.
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Affiliation(s)
- Christopher P Ptak
- Department of Population Medicine and Diagnostic Sciences and ‡Department of Molecular Medicine, College of Veterinary Medicine, Cornell University , Ithaca, New York 14853, United States
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17
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Evaluation of recombinant LigB antigen-based indirect ELISA and latex agglutination test for the serodiagnosis of bovine leptospirosis in India. Mol Cell Probes 2014; 28:141-6. [DOI: 10.1016/j.mcp.2014.01.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 12/28/2013] [Accepted: 01/01/2014] [Indexed: 10/25/2022]
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18
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Characterisation of the Proteome of Leptospira interrogans Serovar Canicola as a Resource for the Identification of Common Serovar Immunogenic Proteins. INTERNATIONAL JOURNAL OF PROTEOMICS 2014; 2014:572901. [PMID: 24987528 PMCID: PMC4058600 DOI: 10.1155/2014/572901] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Revised: 04/24/2014] [Accepted: 04/24/2014] [Indexed: 11/18/2022]
Abstract
Over 230 serovars of Leptospira interrogans have been identified; however few have been completely characterised. The aim of this study was to characterise the proteome of serovar Canicola and to compare this against the serovars of Copenhageni and Pomona. 2D-LC/MS analysis identified 1653 Leptospira proteins in serovar Canicola; 60 of these proteins were common to Copenhageni and Pomona, 16 of which are known to be immunogenic. This study provides the first reported proteome for serovar Canicola and suggests that proteomic comparison of different serovars could be used as a tool for identification of novel target molecules for vaccine development.
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Alizadeh SA, Eshraghi SS, Pourmand MR, Naserpour T, Abdollahpour G, Rahimiforoshani A, Najafipour R. Diagnostic efficacy of lsa63 antigen for human leptospirosis. IRANIAN RED CRESCENT MEDICAL JOURNAL 2014; 16:e14753. [PMID: 24829775 PMCID: PMC4005437 DOI: 10.5812/ircmj.14753] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 11/14/2013] [Accepted: 12/18/2013] [Indexed: 11/16/2022]
Abstract
BACKGROUND Timely diagnosis of leptospirosis is essential for early and effective treatment, for there are many differential diagnoses for it.. Leptospiral researchers have an increasing interest in developing new serological methods with recombinant antigens to improve the Leptospirosis diagnosis. Several serological tests have been developed for the proper diagnosis of leptospirosis. OBJECTIVES To improve the previous works we developed an enzyme linked immunosorbent assay (ELISA) with novel recombinant leptospiral surface adhesion (Lsa63) protein to offer a new test. MATERIALS AND METHODS In an experimental study, Recombinant Lsa63 (rLsa63) was produced in Escherishia coli (E.coli) BL21 (DE3). By using rLsa63, we generated IgM and IgG ELISA. Performance of these tests was compared to microscopic agglutination golden test (MAT). Two hundred twenty human serum samples were obtained from individuals suspicious of leptospirosis who were referred to Guilan Province Central Leptospira Laboratory for definitive diagnosis. The sensitivity, specificity and other statistical indexes of Lsa63-ELISAs were also determined. RESULTS Among 220 serum samples, 30% (n = 65) had positive MAT responses, and also 38% (n = 84) and 40.9% (n = 90) showed positive reaction to IgG and IgM rLsa63-ELISA, respectively. The sensitivity, specificity and accuracy were 93.8%, 81.29 % and 85.0 for IgM-Lsa63- ELISA and 83.07, 80, 64 and 81.36 for IgG-Lsa63- ELISA, respectively. CONCLUSIONS Our results demonstrated that the sensitivity and specificity of Lsa63-ELISAs are promising for the detection of Leptospira serovars.
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Affiliation(s)
- Safar Ali Alizadeh
- Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, IR Iran
| | - Seyyed Saeed Eshraghi
- Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, IR Iran
- Corresponding Author: Seyyed Saeed Eshraghi, Department of Pathobiology, Tehran University of Medical Sciences, Poursina St., Tehran, IR Iran. Tel: +98-2188994823, E-mail:
| | - Mohammad Reza Pourmand
- Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, IR Iran
| | - Taghi Naserpour
- Department of Microbiology, Molecular Research Center, Qazvin University of Medical Sciences, Qazvin, IR Iran
| | | | - Abbas Rahimiforoshani
- Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, IR Iran
| | - Reza Najafipour
- Department of Biochemistry, Genetics Research Center, Qazvin University of Medical Sciences, Qazvin, IR Iran
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20
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Xu C, Loftis A, Ahluwalia SK, Gao D, Verma A, Wang C, Kaltenboeck B. Diagnosis of canine leptospirosis by a highly sensitive FRET-PCR targeting the lig genes. PLoS One 2014; 9:e89507. [PMID: 24586833 PMCID: PMC3933566 DOI: 10.1371/journal.pone.0089507] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 01/19/2014] [Indexed: 11/20/2022] Open
Abstract
Canine leptospirosis is underdiagnosed due to its wide spectrum of clinical presentations and the lack of a rapid and sensitive test for the accurate diagnosis of acute and chronic infections. In this study, we developed a highly sensitive and specific fluorescence resonance energy transfer (FRET)-PCR to detect common pathogenic leptospires in dogs, including Leptospira interrogans serovars Autumnalis, Canicola, Copenhageni (Icterohaemorrhagiae serogroup) and Pomona, and Leptospira kirschneri serovar Grippotyphosa. This PCR targets the lig genes, exclusively found in the pathogenic Leptospira species but not in saprophytic species (L. biflexa). A robust, high-stringency step-down real-time platform was coupled to the highly specific detection of leptospiral DNA by fluorescently labeled FRET probes. This enabled the detection of a single copy of the lig gene in a PCR containing DNA from up to 50 µL canine blood or 400 µL urine. Sensitivity determination by use of limiting serial dilutions of extracted leptospiral DNA indicated that the lig FRET-PCR we established was almost 100-fold more sensitive than the widely accepted lipL32 SYBR assay and 10-fold more sensitive than a 16S rRNA TaqMan assay. Application of this method to 207 dogs with potential leptospiral infection enabled us to diagnose three cases of canine leptospirosis characterized by low amounts of leptospiral DNA in body fluids. Detection of canine leptospirosis with the lig FRET-PCR was more sensitive with the lig FRET-PCR than with the 16S rRNA TaqMan PCR, which detected only 2 of the 3 cases, and the lipL32 SYBR PCR, which detected none of the 3 dogs with leptospirosis.
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MESH Headings
- Agglutination Tests
- Animals
- Base Sequence
- DNA, Bacterial/blood
- DNA, Bacterial/genetics
- DNA, Bacterial/urine
- Dog Diseases/diagnosis
- Dog Diseases/genetics
- Dog Diseases/microbiology
- Dogs
- Fluorescence Resonance Energy Transfer/veterinary
- Genes, Bacterial/genetics
- Leptospira/genetics
- Leptospira/pathogenicity
- Leptospirosis/diagnosis
- Leptospirosis/genetics
- Leptospirosis/veterinary
- Molecular Sequence Data
- RNA, Ribosomal, 16S/blood
- RNA, Ribosomal, 16S/genetics
- RNA, Ribosomal, 16S/urine
- Real-Time Polymerase Chain Reaction/veterinary
- Sequence Homology, Nucleic Acid
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Affiliation(s)
- Chuanling Xu
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, United States of America
| | - Amanda Loftis
- Department of Biomedical Sciences, Ross University School of Veterinary Medicine, St. Kitts, West Indies
| | - Sudhir K. Ahluwalia
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, United States of America
| | - Dongya Gao
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, United States of America
| | - Ashutosh Verma
- Department of Biomedical Sciences, Ross University School of Veterinary Medicine, St. Kitts, West Indies
| | - Chengming Wang
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, United States of America
| | - Bernhard Kaltenboeck
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, United States of America
- * E-mail:
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Serodiagnosis of equine leptospirosis by enzyme-linked immunosorbent assay using four recombinant protein markers. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2014; 21:478-83. [PMID: 24451330 DOI: 10.1128/cvi.00649-13] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Leptospirosis, caused by Leptospira spp., is one of the most common zoonotic diseases in the world. We tested four recombinant proteins of Leptospira interrogans, namely, rLipL21, rLoa22, rLipL32, and rLigACon4-8, to evaluate their potential for use as antigens for the diagnosis of equine leptospirosis. We employed equine sera (n = 130) that were microscopic agglutination test (MAT) negative and sera (n = 176) that were MAT positive for the 5 serovars that most commonly cause equine leptospirosis. The sensitivity and specificity of ELISA compared to MAT were 82.39% and 86.15%, respectively, for LigACon4-8, 77.84% and 92.31%, respectively, for Loa22, 77.84% and 86.15%, respectively, for LipL32, and 84.66% and 83.85%, respectively, for LipL21. When one of the two antigens was test positive, the sensitivity and specificity of ELISA were 93.75% and 78.46%, respectively, for rLigACon4-8 and LipL32, 93.18% and 76.15%, respectively, for rLigACon4-8 and LipL21, 89.77% and 80.77%, respectively, for rLigACon4-8 and Loa22, 91.48% and 78.46%, respectively, for LipL21 and Loa22, 93.75% and 76.92%, respectively, for LipL21 and LipL32, and 90.34% and 80.77%, respectively, for Loa22 and LipL32. In conclusion, we have developed an indirect ELISA utilizing rLigACon4-8, rLoa22, rLipL32, and rLipL21 as diagnostic antigens for equine leptospirosis. The use of four antigens in the ELISA was found to be sensitive and specific, the assay was easy to perform, and the results concurred with the results of the standard Leptospira MAT.
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Fernandes LGV, Vieira ML, Alves IJ, de Morais ZM, Vasconcellos SA, Romero EC, Nascimento ALTO. Functional and immunological evaluation of two novel proteins of Leptospira spp. Microbiology (Reading) 2014; 160:149-164. [DOI: 10.1099/mic.0.072074-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
This work shows the production and characterization of two novel putative lipoproteins encoded by the genes LIC10645 and LIC10731 identified in the genome sequences of Leptospira
interrogans. In silico conservation analysis indicated that the proteins are well conserved among pathogenic leptospiral serovars and species. Recombinant proteins were obtained in Escherichia coli BL21(DE3) Star pLysS strain, purified by metal-affinity chromatography, and used for characterization and immunological evaluations. Recombinant proteins were capable of eliciting a combination of humoral and cellular immune responses in animal models, and could be recognized by antibodies present in human serum samples. The recombinant proteins Lsa44 and Lsa45 were able to bind laminin, and were named Lsa44 and Lsa45 for leptospiral surface adhesins of 44 and 45 kDa, respectively. The attachment to laminin was dose-responsive with K
D values of 108.21 and 250.38 nM for Lsa44 and Lsa45, respectively. Moreover, these proteins interact with plasminogen (PLG) with K
D values of 53.56 and 36.80 nM, respectively. PLG bound to the recombinant proteins could be converted to plasmin (PLA) in the presence of an activator. Cellular localization assays suggested that the Lsa44 and Lsa45 were surface-exposed. These are versatile proteins capable of interacting with laminin and PLG/PLA, and hence could mediate bacterial adhesion and contribute to tissue penetration.
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Affiliation(s)
- Luis G. V. Fernandes
- Interunidades em Biotecnologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
- Centro de Biotecnologia, Instituto Butantan, Avenida Vital Brazil 1500, 05503-900 São Paulo, SP, Brazil
| | - Monica L. Vieira
- Interunidades em Biotecnologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
- Centro de Biotecnologia, Instituto Butantan, Avenida Vital Brazil 1500, 05503-900 São Paulo, SP, Brazil
| | - Ivy J. Alves
- Centro de Biotecnologia, Instituto Butantan, Avenida Vital Brazil 1500, 05503-900 São Paulo, SP, Brazil
| | - Zenaide M. de Morais
- Laboratório de Zoonoses Bacterianas do VPS, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, Brazil
| | - Silvio A. Vasconcellos
- Laboratório de Zoonoses Bacterianas do VPS, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, Brazil
| | - Eliete C. Romero
- Divisão de Biologia Medica, Instituto Adolfo Lutz, São Paulo, Brazil
| | - Ana L. T. O. Nascimento
- Centro de Biotecnologia, Instituto Butantan, Avenida Vital Brazil 1500, 05503-900 São Paulo, SP, Brazil
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Identification of seroreactive proteins of Leptospira interrogans serovar copenhageni using a high-density protein microarray approach. PLoS Negl Trop Dis 2013; 7:e2499. [PMID: 24147173 PMCID: PMC3798601 DOI: 10.1371/journal.pntd.0002499] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Accepted: 09/10/2013] [Indexed: 11/19/2022] Open
Abstract
Background Leptospirosis is a widespread zoonotic disease worldwide. The lack of an adequate laboratory test is a major barrier for diagnosis, especially during the early stages of illness, when antibiotic therapy is most effective. Therefore, there is a critical need for an efficient diagnostic test for this life threatening disease. Methodology In order to identify new targets that could be used as diagnostic makers for leptopirosis, we constructed a protein microarray chip comprising 61% of Leptospira interrogans proteome and investigated the IgG response from 274 individuals, including 80 acute-phase, 80 convalescent-phase patients and 114 healthy control subjects from regions with endemic, high endemic, and no endemic transmission of leptospirosis. A nitrocellulose line blot assay was performed to validate the accuracy of the protein microarray results. Principal findings We found 16 antigens that can discriminate between acute cases and healthy individuals from a region with high endemic transmission of leptospirosis, and 18 antigens that distinguish convalescent cases. Some of the antigens identified in this study, such as LipL32, the non-identical domains of the Lig proteins, GroEL, and Loa22 are already known to be recognized by sera from human patients, thus serving as proof-of-concept for the serodiagnostic antigen discovery approach. Several novel antigens were identified, including the hypothetical protein LIC10215 which showed good sensitivity and specificity rates for both acute- and convalescent-phase patients. Conclusions Our study is the first large-scale evaluation of immunodominant antigens associated with naturally acquired leptospiral infection, and novel as well as known serodiagnostic leptospiral antigens that are recognized by antibodies in the sera of leptospirosis cases were identified. The novel antigens identified here may have potential use in both the development of new tests and the improvement of currently available assays for diagnosing this neglected tropical disease. Further research is needed to assess the utility of these antigens in more deployable diagnostic platforms. Leptospirosis is an infectious zoonotic disease that causes non-specific signs and symptoms in humans, which hampers the clinical diagnosis and treatment by physicians. Complications can occur if the proper treatment is not initiated early in the course of illness. Although the early diagnosis is critical for preventing unnecessary complications, currently available tests do not exhibit sufficient diagnostic sensitivity in the beginning of disease. We took advantage of high throughput techniques to perform an embracing study of the humoral immune response to the bacteria in order to identify antigens that could be used in a new test for the diagnosis of leptospirosis. A protein microarray chip containing 2,241 leptospiral proteins was constructed and probed with serum samples from patients and healthy individuals. We identified 24 proteins that are recognized by patients' sera but not by healthy individuals. These proteins are potential diagnostic markers, especially the ones identified for acute-phase patients, which can discriminate between a positive and a negative leptospirosis case within a few days after onset of symptoms. This work establishes the protein microarray approach for improving our understanding of the serological response to leptospirosis. Further research is needed to assess the performance of these antigens in the clinical setting.
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24
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Development of an enzyme-linked immunosorbent assay using a recombinant LigA fragment comprising repeat domains 4 to 7.5 as an antigen for diagnosis of equine leptospirosis. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2013; 20:1143-9. [PMID: 23720368 DOI: 10.1128/cvi.00245-13] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Leptospira immunoglobulin (Ig)-like (Lig) proteins are a novel family of surface-associated proteins in which the N-terminal 630 amino acids are conserved. In this study, we truncated the LigA conserved region into 7 fragments comprising the 1st to 3rd (LigACon1-3), 4th to 7.5th (LigACon4-7.5), 4th (LigACon4), 4.5th to 5.5th (LigACon4.5-5.5), 5.5th to 6.5th (LigACon5.5-6.5), 4th to 5th (LigACon4-5), and 6th to 7.5th (LigACon6-7.5) repeat domains. All 7 recombinant Lig proteins were screened using a slot-shaped dot blot assay for the diagnosis of equine leptospirosis. Our results showed that LigACon4-7.5 is the best candidate diagnostic antigen in a slot-shaped dot blot assay. LigACon4-7.5 was further evaluated as an indirect enzyme-linked immunosorbent assay (ELISA) antigen for the detection of Leptospira antibodies in equine sera. This assay was evaluated with equine sera (n = 60) that were microscopic agglutination test (MAT) negative and sera (n = 220) that were MAT positive to the 5 serovars that most commonly cause equine leptospirosis. The indirect ELISA results showed that at a single serum dilution of 1:250, the sensitivity and specificity of ELISA were 80.0% and 87.2%, respectively, compared to those of MAT. In conclusion, an indirect ELISA was developed utilizing a recombinant LigA fragment comprising the 4th to 7.5th repeat domain (LigACon4-7.5) as a diagnostic antigen for equine leptospirosis. This ELISA was found to be sensitive and specific, and it yielded results that concurred with those of the standard MAT.
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Ching ATC, Fávaro RD, Lima SS, Chaves ADAM, de Lima MA, Nader HB, Abreu PAE, Ho PL. Leptospira interrogans shotgun phage display identified LigB as a heparin-binding protein. Biochem Biophys Res Commun 2012; 427:774-9. [PMID: 23044419 DOI: 10.1016/j.bbrc.2012.09.137] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Accepted: 09/28/2012] [Indexed: 10/27/2022]
Abstract
LigB is an adhesin from pathogenic Leptospira that is able to bind to extracellular matrix and is considered a virulence factor. A shotgun phage display genomic library was constructed and used for panning against Heparan Sulfate Proteoglycan (HSPG). A phage clone encoding part of LigB protein was selected in panning experiments and showed specific binding to heparin. To validate the selected clone, fragments of LigB were produced as recombinant proteins and showed affinity to heparin and to mammalian cells. Heparin was also able to reduce the binding of rLB-Ct to mammalian cells. Our data suggests that the glycosaminoglycan moiety of the HSPG is responsible for its binding and could mediate the attachment of the recombinant protein rLB-Ct. Thus, heparin may act as a receptor for Leptospira to colonize and to invade the host tissue.
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Affiliation(s)
- Ana Tung Ching Ching
- Centro de Biotecnologia, Instituto Butantan, CEP 05503-900 São Paulo, SP, Brazil
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Castiblanco-Valencia MM, Fraga TR, Silva LBD, Monaris D, Abreu PAE, Strobel S, Józsi M, Isaac L, Barbosa AS. Leptospiral Immunoglobulin-like Proteins Interact With Human Complement Regulators Factor H, FHL-1, FHR-1, and C4BP. J Infect Dis 2012; 205:995-1004. [DOI: 10.1093/infdis/jir875] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
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Monte LG, Conceição FR, Coutinho ML, Seixas FK, da Silva EF, Vasconcellos FA, deCastro LAS, Hartleben CP, Dellagostin OA, Aleixo JAG. Monoclonal antibodies against the leptospiral immunoglobulin-like proteins A and B conserved regions. Comp Immunol Microbiol Infect Dis 2011; 34:441-6. [PMID: 21903270 DOI: 10.1016/j.cimid.2011.08.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Revised: 08/11/2011] [Accepted: 08/17/2011] [Indexed: 12/22/2022]
Abstract
Leptospirosis is an infectious disease caused by pathogenic spirochetes of the genus Leptospira that affects humans and a wide variety of animals. Recently the genomes of Leptospira interrogans, Leptospira borgpetersenii and Leptospira biflexa species were sequenced allowing the identification of new virulence factors involved in survival and pathogenesis of bacteria. LigA and LigB are surface-exposed bacterial adhesins whose expression is correlated with the virulence of Leptospira strains. In this study, we produced and characterized five monoclonal antibodies (MAbs) against a recombinant fragment of LigB (rLigBrep) with approximately 54kDa that comprise the portions of LigA and LigB (domains 2-7). The 5 MAbs obtained were of the IgG1 (2) and IgG2b (3) isotypes and their affinity constants for rLigBrep ranged from 7×10(7) M(-1) to 4×10(8) M(-1). The MAbs were able to react with the native antigen on the L. interrogans, L. borgpetersenii and Leptospira noguchii surfaces by indirect immunofluorescence, immunoblotting and immunoelectron microscopy. These results demonstrate that the MAbs anti-rLigBrep can be useful to complement genetic studies and to aid studies aiming understanding the role of Lig proteins in Leptospira pathogenesis and the development of Lig-based vaccines and improved diagnostic tests for leptospirosis.
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Affiliation(s)
- Leonardo G Monte
- Laboratório de Imunologia Aplicada, Núcleo de Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, P.O. Box 354, 96010-900, Pelotas, RS, Brazil.
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Cao Y, Faisal SM, Yan W, Chang YC, McDonough SP, Zhang N, Akey BL, Chang YF. Evaluation of novel fusion proteins derived from extracellular matrix binding domains of LigB as vaccine candidates against leptospirosis in a hamster model. Vaccine 2011; 29:7379-86. [PMID: 21803087 DOI: 10.1016/j.vaccine.2011.07.070] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Revised: 07/15/2011] [Accepted: 07/17/2011] [Indexed: 10/17/2022]
Abstract
Leptospira binds to host extracellular matrix (ECM) through surface exposed outer membrane proteins called adhesin in order to initiate infection. Of various adhesins present on the surface of the spirochete, Leptospira-immunoglobulin like proteins (Lig proteins) and LipL32 are most abundant, widely distributed among pathogenic serovars and well characterized. Various fragments of Lig proteins (Ligcon4, Ligcon4-7.5, LigBcen2) and C-terminus fragment of LipL32 all of that bind to host ECM were fused, expressed and purified in soluble form as fusion proteins. Four week hamsters were immunized subcutaneously with various fusion proteins emulsified in EMULSIGEN-D adjuvant and subsequently boosted at 3 weeks. The protective efficacy of these novel fusion proteins was evaluated against subsequent challenge with highly virulent L. interrogans serovar Pomona (MLD50-100). Our results indicate that fusion protein based vaccine induced significant protection against acute infection with respect to PBS-adjuvant vaccinated controls as revealed by enhanced survival and reduced pulmonary hemorrhage. Moreover, the protection mediated by these novel proteins was higher than that of conserved region of Lig protein (Ligcon, established protective antigen) and correlated to the level of antibodies. LipL32 failed to impart significant protection, however fusing its immunogenic C-terminus domain to Lig fragments slightly delayed the morbidity of the infected animals. Our results demonstrate that this novel strategy could be promising in developing effective subunit vaccine to combat this zoonotic infection.
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Affiliation(s)
- Yongguo Cao
- Department of Population medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, United States
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Yan W, Faisal S, Divers T, McDonough S, Akey B, Chang YF. Experimental Leptospira interrogans Serovar Kennewicki Infection of Horses. J Vet Intern Med 2011. [DOI: 10.1111/j.1939-1676.2010.00507.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Cerqueira GM, Souza NM, Araújo ER, Barros AT, Morais ZM, Vasconcellos SA, Nascimento ALTO. Development of transcriptional fusions to assess Leptospira interrogans promoter activity. PLoS One 2011; 6:e17409. [PMID: 21445252 PMCID: PMC3060810 DOI: 10.1371/journal.pone.0017409] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2010] [Accepted: 01/31/2011] [Indexed: 11/29/2022] Open
Abstract
Background Leptospirosis is a zoonotic infectious disease that affects both humans and animals. The existing genetic tools for Leptospira spp. have improved our understanding of the biology of this spirochete as well as the interaction of pathogenic leptospires with the mammalian host. However, new tools are necessary to provide novel and useful information to the field. Methodology and Principal Findings A series of promoter-probe vectors carrying a reporter gene encoding green fluorescent protein (GFP) were constructed for use in L. biflexa. They were tested by constructing transcriptional fusions between the lipL41, Leptospiral Immunoglobulin-like A (ligA) and Sphingomielynase 2 (sph2) promoters from L. interrogans and the reporter gene. ligA and sph2 promoters were the most active, in comparison to the lipL41 promoter and the non-induced controls. The results obtained are in agreement with LigA expression from the L. interrogans Fiocruz L1-130 strain. Conclusions The novel vectors facilitated the in vitro evaluation of L. interrogans promoter activity under defined growth conditions which simulate the mammalian host environment. The fluorescence and rt-PCR data obtained closely reflected transcriptional regulation of the promoters, thus demonstrating the suitability of these vectors for assessing promoter activity in L. biflexa.
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Lin YP, McDonough SP, Sharma Y, Chang YF. Leptospira immunoglobulin-like protein B (LigB) binding to the C-terminal fibrinogen αC domain inhibits fibrin clot formation, platelet adhesion and aggregation. Mol Microbiol 2011; 79:1063-76. [PMID: 21219469 DOI: 10.1111/j.1365-2958.2010.07510.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Leptospira immunoglobulin-like (Lig) proteins including LigA and LigB are adhesins that bind to fibronectin, collagen, laminin and elastin. In addition, Lig proteins are fibrinogen (Fg)-binding proteins, although the physiological role of the Lig-Fg interaction is unclear. In this study, a previously identified Fg-binding region, LigBCen2 (amino acids 1014-1165 of LigB), has been further localized to LigBCen2R, which consists of the partial 11th and entire 12th Ig-like domain (amino acids 1014-1119). LigBCen2R was found to bind to the C-terminal αC domain of Fg (FgαCC; amino acids 392-644 in Fg α chain; isothermal titration calorimetry, K(D) = 0.375 µM; fluorescence spectrometry, K(D) = 0.364 µM). The quenching and blue shift observed for the maximum wavelength intensities of the tryptophan fluorescence spectra for FgαCCY570W upon LigBCen2RW1073C binding suggested an RGD motif close to the sole tryptophan on FgαCCY570W was buried in LigBCen2R upon saturation with FgαCC. A conformational change in LigBCen2R when bound to the FgαCC RGD motif blocked further binding to integrin α(IIb) β3 on platelets, thus preventing their aggregation. LigBCen2R binding to FgαCC reduced clot formation but did not affect plasminogen and tissue-type plasminogen activator interactions with FgαCC. This study is the first to report that a spirochaetal protein binds to the C-terminal αC domain of Fg, which regulates thrombosis and fibrinolysis, and may help explain the pulmonary haemorrhage and thrombocytopenia seen in clinical cases of leptospirosis.
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Affiliation(s)
- Yi-Pin Lin
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, NY, USA
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Raman R, Rajanikanth V, Palaniappan RUM, Lin YP, He H, McDonough SP, Sharma Y, Chang YF. Big domains are novel Ca²+-binding modules: evidences from big domains of Leptospira immunoglobulin-like (Lig) proteins. PLoS One 2010; 5:e14377. [PMID: 21206924 PMCID: PMC3012076 DOI: 10.1371/journal.pone.0014377] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2010] [Accepted: 11/24/2010] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Many bacterial surface exposed proteins mediate the host-pathogen interaction more effectively in the presence of Ca²+. Leptospiral immunoglobulin-like (Lig) proteins, LigA and LigB, are surface exposed proteins containing Bacterial immunoglobulin like (Big) domains. The function of proteins which contain Big fold is not known. Based on the possible similarities of immunoglobulin and βγ-crystallin folds, we here explore the important question whether Ca²+ binds to a Big domains, which would provide a novel functional role of the proteins containing Big fold. PRINCIPAL FINDINGS We selected six individual Big domains for this study (three from the conserved part of LigA and LigB, denoted as Lig A3, Lig A4, and LigBCon5; two from the variable region of LigA, i.e., 9(th) (Lig A9) and 10(th) repeats (Lig A10); and one from the variable region of LigB, i.e., LigBCen2. We have also studied the conserved region covering the three and six repeats (LigBCon1-3 and LigCon). All these proteins bind the calcium-mimic dye Stains-all. All the selected four domains bind Ca²+ with dissociation constants of 2-4 µM. Lig A9 and Lig A10 domains fold well with moderate thermal stability, have β-sheet conformation and form homodimers. Fluorescence spectra of Big domains show a specific doublet (at 317 and 330 nm), probably due to Trp interaction with a Phe residue. Equilibrium unfolding of selected Big domains is similar and follows a two-state model, suggesting the similarity in their fold. CONCLUSIONS We demonstrate that the Lig are Ca²+-binding proteins, with Big domains harbouring the binding motif. We conclude that despite differences in sequence, a Big motif binds Ca²+. This work thus sets up a strong possibility for classifying the proteins containing Big domains as a novel family of Ca²+-binding proteins. Since Big domain is a part of many proteins in bacterial kingdom, we suggest a possible function these proteins via Ca²+ binding.
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Affiliation(s)
- Rajeev Raman
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Hyderabad, India
| | - V. Rajanikanth
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Hyderabad, India
| | - Raghavan U. M. Palaniappan
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | - Yi-Pin Lin
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | - Hongxuan He
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
- Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Sean P. McDonough
- Department of Biomedical Science, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | - Yogendra Sharma
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Hyderabad, India
- * E-mail: (YS); (YC)
| | - Yung-Fu Chang
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
- * E-mail: (YS); (YC)
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Hsu SH, Lo YY, Tung JY, Ko YC, Sun YJ, Hung CC, Yang CW, Tseng FG, Fu CC, Pan RL. Leptospiral outer membrane lipoprotein LipL32 binding on toll-like receptor 2 of renal cells as determined with an atomic force microscope. Biochemistry 2010; 49:5408-17. [PMID: 20513152 DOI: 10.1021/bi100058w] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Leptopirosis is a renal disease caused by pathogenic Leptospira that primarily infects the renal proximal tubules, consequently resulting in severe tubular injuries and malfunctions. The protein extracted from the outer membrane of this pathogenic strain contains a major component of a 32 kDa lipoprotein (LipL32), which is absent in the counter membrane of nonpathogenic strains and has been identified as a crucial factor for host cell infection. Previous studies showed that LipL32 induced inflammatory responses and interacted with the extracellular matrix (ECM) of the host cell. However, the exact relationship between LipL32-mediated inflammatory responses and ECM binding is still unknown. In this study, an atomic force microscope with its tip modified by purified LipL32 was used to assess the interaction between LipL32 and cell surface receptors. Furthermore, an antibody neutralization technique was employed to identify Toll-like receptor 2 (TLR2) but not TLR4 as the major target of LipL32 attack. The interaction force between LipL32 and TLR2 was measured as approximately 59.5 +/- 8.7 pN, concurring with the theoretical value for a single-pair molecular interaction. Moreover, transformation of a TLR deficient cell line with human TLR2 brought the interaction force from the basal level to approximately 60.4 +/- 11.5 pN, confirming unambiguously TLR2 as counter receptor for LipL32. The stimulation of CXCL8/IL-8 expression by full-length LipL32 as compared to that without the N-terminal signal peptide domain suggests a significant role of the signal peptide of the protein in the inflammatory responses. This study provides direct evidence that LipL32 binds to TLR2, but not TLR4, on the cell surface, and a possible mechanism for the virulence of leptospirosis is accordingly proposed.
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Affiliation(s)
- Shen-Hsing Hsu
- Department of Life Science and Institute of Bioinformatics and Structural Biology, College of Life Science, National Tsing Hua University, Hsin Chu 30013, Taiwan, Republic of China
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Lin YP, McDonough SP, Sharma Y, Chang YF. The terminal immunoglobulin-like repeats of LigA and LigB of Leptospira enhance their binding to gelatin binding domain of fibronectin and host cells. PLoS One 2010; 5:e11301. [PMID: 20585579 PMCID: PMC2892007 DOI: 10.1371/journal.pone.0011301] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Accepted: 05/19/2010] [Indexed: 01/17/2023] Open
Abstract
Leptospira spp. are pathogenic spirochetes that cause the zoonotic disease leptospirosis. Leptospiral immunoglobulin (Ig)-like protein B (LigB) contributes to the binding of Leptospira to extracellular matrix proteins such as fibronectin, fibrinogen, laminin, elastin, tropoelastin and collagen. A high-affinity Fn-binding region of LigB has been localized to LigBCen2, which contains the partial 11th and full 12th Ig-like repeats (LigBCen2R) and 47 amino acids of the non-repeat region (LigBCen2NR) of LigB. In this study, the gelatin binding domain of fibronectin was shown to interact with LigBCen2R (K(D) = 1.91+/-0.40 microM). Not only LigBCen2R but also other Ig-like domains of Lig proteins including LigAVar7'-8, LigAVar10, LigAVar11, LigAVar12, LigAVar13, LigBCen7'-8, and LigBCen9 bind to GBD. Interestingly, a large gain in affinity was achieved through an avidity effect, with the terminal domains, 13th (LigA) or 12th (LigB) Ig-like repeat of Lig protein (LigAVar7'-13 and LigBCen7'-12) enhancing binding affinity approximately 51 and 28 fold, respectively, compared to recombinant proteins without this terminal repeat. In addition, the inhibited effect on MDCKs cells can also be promoted by Lig proteins with terminal domains, but these two domains are not required for gelatin binding domain binding and cell adhesion. Interestingly, Lig proteins with the terminal domains could form compact structures with a round shape mediated by multidomain interaction. This is the first report about the interaction of gelatin binding domain of Fn and Lig proteins and provides an example of Lig-gelatin binding domain binding mediating bacterial-host interaction.
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Affiliation(s)
- Yi-Pin Lin
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | - Sean P. McDonough
- Department of Biomedical Science, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | | | - Yung-Fu Chang
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
- * E-mail:
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Sankar S, Harshan HM, Somarajan SR, Srivastava SK. Evaluation of a recombinant LigB protein of Leptospira interrogans serovar Canicola in an enzyme-linked immunosorbent assay for the serodiagnosis of bovine leptospirosis. Res Vet Sci 2009; 88:375-8. [PMID: 20022618 DOI: 10.1016/j.rvsc.2009.11.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2008] [Revised: 10/30/2009] [Accepted: 11/04/2009] [Indexed: 10/20/2022]
Abstract
A recombinant leptospiral lipoprotein, LigB, was evaluated for use in the diagnosis of bovine leptospirosis by enzyme-linked immunosorbent assay (rLigB IgG ELISA). The standard reference test (Microscopic agglutination test, MAT) of 200 serum samples from cattle suspected of leptospirosis showed that 95 (47.5%) samples had positive agglutination titres, which ranged from 100 to 1600. In rLigB IgG ELISA, 49% of the samples were positive. Sensitivity of IgG ELISA for 95 bovine sera, which had MAT titres of greater than or equal to 100, were 100%. ELISA showed a specificity of 97.1% with 105 bovine sera, which were negative at a 1:50 dilution in MAT for Leptospira interrogans serovars. The results of ELISA and MAT correspond very good. When analytical specificity of IgG ELISA was evaluated using bovine serum samples from animals showing the serum antibodies to other pathogens, no cross-reaction was observed. Thus the recombinant LigB IgG ELISA can be used instead of the MAT as an aid to the diagnosis of bovine leptospirosis.
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Affiliation(s)
- Surya Sankar
- Division of Bacteriology and Mycology, Indian Veterinary Research Institute, Izatnagar 243122, Uttar Pradesh, India.
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Lin YP, Greenwood A, Nicholson LK, Sharma Y, McDonough SP, Chang YF. Fibronectin binds to and induces conformational change in a disordered region of leptospiral immunoglobulin-like protein B. J Biol Chem 2009; 284:23547-57. [PMID: 19581300 PMCID: PMC2749129 DOI: 10.1074/jbc.m109.031369] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2009] [Indexed: 11/06/2022] Open
Abstract
Leptospira interrogans is a pathogenic spirochete that causes disease in both humans and animals. LigB (Leptospiral immunoglobulin-like protein B) contributes to the binding of Leptospira to extracellular matrix proteins such as fibronectin (Fn), fibrinogen, laminin, and collagen. A high affinity Fn-binding region of LigB has been recently localized to LigBCen2, which contains the partial eleventh and full twelfth immunoglobulin-like repeats (LigBCen2R) and 47 amino acids of the non-repeat region (LigBCen2NR) of LigB. In this study, LigBCen2NR was shown to bind to the N-terminal domain (NTD) of Fn (K(D) = 379 nm) by an enzyme-linked immunosorbent assay and isothermal titration calorimetry. Interestingly, this sequence was not observed to adopt secondary structure by far UV circular dichroism or by differential scanning calorimetry, in agreement with computer-based secondary structure predictions. A low partition coefficient (K(av)) measured with gel permeation chromatography, a high hydrodynamic radius (R(h)) measured with dynamic light scattering, and the insensitivity of the intrinsic viscosity to guanidine hydrochloride treatment all suggest that LigBCen2NR possesses an extended and disordered structure. Two-dimensional (15)N-(1)H HSQC NMR spectra of intact LigBCen2 in the absence and presence of NTD are consistent with these observations, suggesting the presence of both a beta-rich region and an unstructured region in LigBCen2 and that the latter of these selectively interacts with NTD. Upon binding to NTD, LigBCen2NR was observed by CD to adopt a beta-strand-rich structure, suggestive of the known beta-zipper mode of NTD binding.
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Affiliation(s)
- Yi-Pin Lin
- From the Department of Population Medicine and Diagnostic Sciences
| | - Alex Greenwood
- Department of Molecular Biology and Genetics, College of Agriculture and Life Science, Cornell University, Ithaca, New York 14853 and
| | - Linda K. Nicholson
- Department of Molecular Biology and Genetics, College of Agriculture and Life Science, Cornell University, Ithaca, New York 14853 and
| | - Yogendra Sharma
- the Center for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
| | - Sean P. McDonough
- Department of Biomedical Sciences, College of Veterinary Medicine, and
| | - Yung-Fu Chang
- From the Department of Population Medicine and Diagnostic Sciences
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Lin YP, Greenwood A, Yan W, Nicholson LK, Sharma Y, McDonough SP, Chang YF. A novel fibronectin type III module binding motif identified on C-terminus of Leptospira immunoglobulin-like protein, LigB. Biochem Biophys Res Commun 2009; 389:57-62. [PMID: 19699715 DOI: 10.1016/j.bbrc.2009.08.089] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Accepted: 08/16/2009] [Indexed: 10/20/2022]
Abstract
Infection by pathogenic strains of Leptospira hinges on the pathogen's ability to adhere to host cells via extracellular matrix such as fibronectin (Fn). Previously, the immunoglobulin-like domains of Leptospira Lig proteins were recognized as adhesins binding to N-terminal domain (NTD) and gelatin binding domain (GBD) of Fn. In this study, we identified another Fn-binding motif on the C-terminus of the Leptospira adhesin LigB (LigBCtv), residues 1708-1712 containing sequence LIPAD with a beta-strand and nascent helical structure. This motif binds to 15th type III modules (15F(3)) (K(D)=10.70 microM), and association (k(on)=600 M(-1)s(-1)) and dissociation (k(off)=0.0129 s(-1)) rate constants represents a slow binding kinetics in this interaction. Moreover, pretreatment of MDCK cells with LigB(1706-1716) blocked the binding of Leptospira by 39%, demonstrating a significant role of LigB(1706-1716) in cellular adhesion. These data indicate that the LIPAD residues (LigB(1708-1712)) of the Leptospira interrogans LigB protein bind 15F(3) of Fn at a novel binding site, and this interaction contributes to adhesion to host cells.
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Affiliation(s)
- Yi-Pin Lin
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
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Blanco R, Takei K, Romero E. Leptospiral glycolipoprotein as a candidate antigen for serodiagnosis of human leptospirosis. Lett Appl Microbiol 2009; 49:267-73. [DOI: 10.1111/j.1472-765x.2009.02650.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Hauk P, Guzzo CR, Ramos HR, Ho PL, Farah CS. Structure and Calcium-Binding Activity of LipL32, the Major Surface Antigen of Pathogenic Leptospira sp. J Mol Biol 2009; 390:722-36. [DOI: 10.1016/j.jmb.2009.05.034] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2009] [Revised: 05/14/2009] [Accepted: 05/15/2009] [Indexed: 10/20/2022]
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Cerqueira GM, McBride AJA, Picardeau M, Ribeiro SG, Moreira ÂN, Morel V, Reis MG, Ko AI, Dellagostin OA. Distribution of the leptospiral immunoglobulin-like (lig) genes in pathogenic Leptospira species and application of ligB to typing leptospiral isolates. J Med Microbiol 2009; 58:1173-1181. [PMID: 19528180 DOI: 10.1099/jmm.0.009175-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The family of leptospiral immunoglobulin-like (lig) genes comprises ligA, ligB and ligC. This study used PCR to demonstrate the presence of lig genes among serovars from a collection of leptospiral strains and clinical isolates. Whilst ligA and ligC appeared to be present in a limited number of pathogenic serovars, the ligB gene was distributed ubiquitously among all pathogenic strains. None of the lig genes were detected among intermediate or saprophytic Leptospira species. It was also shown that, similar to the previously characterized secY gene, a short specific PCR fragment of ligB could be used to correctly identify pathogenic Leptospira species. These findings demonstrate that ligB is widely present among pathogenic strains and may be useful for their reliable identification and classification.
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Affiliation(s)
- Gustavo M Cerqueira
- Institut Pasteur, Unité de Biologie des Spirochètes, 75015 Paris, France.,Federal University of Pelotas, Biotechnology Centre, PO Box 354, 96010-900 Pelotas, RS, Brazil
| | - Alan J A McBride
- Gonçalo Moniz Research Centre, Oswaldo Cruz Foundation, Brazilian Ministry of Health, Salvador, BA, Brazil
| | - Mathieu Picardeau
- Institut Pasteur, Unité de Biologie des Spirochètes, 75015 Paris, France
| | - Samuel G Ribeiro
- Federal University of Pelotas, Biotechnology Centre, PO Box 354, 96010-900 Pelotas, RS, Brazil
| | - Ângela N Moreira
- Federal University of Pelotas, Biotechnology Centre, PO Box 354, 96010-900 Pelotas, RS, Brazil
| | - Viviane Morel
- Institut Pasteur, Unité de Biologie des Spirochètes, 75015 Paris, France
| | - Mitermayer G Reis
- Gonçalo Moniz Research Centre, Oswaldo Cruz Foundation, Brazilian Ministry of Health, Salvador, BA, Brazil
| | - Albert I Ko
- Division of International Medicine and Infectious Disease, Weill Medical College of Cornell University, New York, NY, USA.,Gonçalo Moniz Research Centre, Oswaldo Cruz Foundation, Brazilian Ministry of Health, Salvador, BA, Brazil
| | - Odir A Dellagostin
- Federal University of Pelotas, Biotechnology Centre, PO Box 354, 96010-900 Pelotas, RS, Brazil
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41
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Lin YP, Lee DW, McDonough SP, Nicholson LK, Sharma Y, Chang YF. Repeated domains of leptospira immunoglobulin-like proteins interact with elastin and tropoelastin. J Biol Chem 2009; 284:19380-91. [PMID: 19473986 DOI: 10.1074/jbc.m109.004531] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Leptospira spp., the causative agents of leptospirosis, adhere to components of the extracellular matrix, a pivotal role for colonization of host tissues during infection. Previously, we and others have shown that Leptospira immunoglobulin-like proteins (Lig) of Leptospira spp. bind to fibronectin, laminin, collagen, and fibrinogen. In this study, we report that Leptospira can be immobilized by human tropoelastin (HTE) or elastin from different tissues, including lung, skin, and blood vessels, and that Lig proteins can bind to HTE or elastin. Moreover, both elastin and HTE bind to the same LigB immunoglobulin-like domains, including LigBCon4, LigBCen7'-8, LigBCen9, and LigBCen12 as demonstrated by enzyme-linked immunosorbent assay (ELISA) and competition ELISAs. The LigB immunoglobulin-like domain binds to the 17th to 27th exons of HTE (17-27HTE) as determined by ELISA (LigBCon4, K(D) = 0.50 microm; LigBCen7'-8, K(D) = 0.82 microm; LigBCen9, K(D) = 1.54 microm; and LigBCen12, K(D) = 0.73 microm). The interaction of LigBCon4 and 17-27HTE was further confirmed by steady state fluorescence spectroscopy (K(D) = 0.49 microm) and ITC (K(D) = 0.54 microm). Furthermore, the binding was enthalpy-driven and affected by environmental pH, indicating it is a charge-charge interaction. The binding affinity of LigBCon4D341N to 17-27HTE was 4.6-fold less than that of wild type LigBCon4. In summary, we show that Lig proteins of Leptospira spp. interact with elastin and HTE, and we conclude this interaction may contribute to Leptospira adhesion to host tissues during infection.
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Affiliation(s)
- Yi-Pin Lin
- Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, New York, USA
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42
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Vieira ML, Pimenta DC, de Morais ZM, Vasconcellos SA, Nascimento ALTO. Proteome analysis of Leptospira interrogans virulent strain. Open Microbiol J 2009; 3:69-74. [PMID: 19590580 PMCID: PMC2698427 DOI: 10.2174/1874285800903010069] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Revised: 04/08/2009] [Accepted: 04/09/2009] [Indexed: 11/22/2022] Open
Abstract
Leptospirosis is a worldwide zoonotic infection of human and veterinary concern. Caused by pathogenic spirochetes of the genus Leptospira, the disease presents greater incidence in tropical and subtropical regions. The identification of proteins that could be involved in the bacteria host interactions may facilitate the search for immune protective antigens. We report the proteomic analysis of Leptospira interrogans serovar Pomona virulent strain LPF cultured from kidney and liver of infected hamsters. Total protein extracts were separated by two-dimensional gel electrophoresis (2-DE), 895 spots were analyzed by MALDI-TOF mass spectrometry (MS), and 286 were identified as leptospiral proteins, corresponding to 108 distinct proteins. These proteins are allocated in all the bacterial cell compartments and are distributed in every functional category. Furthermore, the previously described, known outer membrane proteins, OmpL1, LipL21, LipL31, LipL32/Hap-1, LipL41, LipL45, LipL46, LruA/LipL71, and OmpA-like protein Loa22 were all recognized. Most importantly, this research work identified 27 novel leptospiral proteins annotated as hypothetical open reading frames (ORFs). We report for the first time an array of proteins of the Leptospira expressed by virulent, low-passage strain. We believe that our studies, together with the genome data will enlighten our understanding of the disease.
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Affiliation(s)
- Monica L Vieira
- Centro de Biotecnologia, Instituto Butantan, Avenida Vital Brazil, 1500, 05503-900, São Paulo, SP, Brazil
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Maneewatch S, Sakolvaree Y, Saengjaruk P, Srimanote P, Tapchaisri P, Tongtawe P, Klaysing B, Wongratanacheewin S, Chongsa-Nguan M, Chaicumpa W. Monoclonal antibodies to LipL32 protect against heterologous Leptospira spp. challenge. Hybridoma (Larchmt) 2009; 27:453-65. [PMID: 19108618 DOI: 10.1089/hyb.2008.0056] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
A non-culture-based leptospirosis vaccine that cross-protects against infection caused by heterologous Leptospira spp. should replace the currently available products, which are qualitatively and quantitatively inadequate. With that in mind, two murine hybridomas secreting monoclonal antibodies (MAb) binding only to homogenates of pathogenic Leptospira spp., and not of the saprophytic L. biflexa, serogroup Patoc, serovar Patoc, were produced. The MAbs of both clones neutralized Leptospira-mediated human red blood cell lysis in vitro and rescued hamsters from lethal infection with heterologous Leptospira spp. The orthologous Leptospira spp. protein carrying the MAb epitope(s) was identified by two-dimensional gel electrophoresis (2DE)-based proteomics and database search. The epitopes of the MAbs were located on the major outer membrane protein LipL32 of the pathogenic Leptospira spp. The MAbs in their humanized version are potential leptospirosis immunotherapeutics. They are also suitable as detection reagents in antigen-based assays for the rapid diagnosis of leptospirosis. Recombinant LipL32 is a good candidate for a broad spectrum, non-culture-based leptospirosis vaccine.
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Affiliation(s)
- Santi Maneewatch
- Faculty of Allied Health Sciences, Thammasat University , Rangsit Center, Pathumthani, Thailand
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Leptospira immunoglobulin-like protein A variable region (LigAvar) incorporated in liposomes and PLGA microspheres produces a robust immune response correlating to protective immunity. Vaccine 2009; 27:378-87. [DOI: 10.1016/j.vaccine.2008.10.089] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Revised: 10/28/2008] [Accepted: 10/29/2008] [Indexed: 11/19/2022]
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Yan W, Faisal SM, McDonough SP, Divers TJ, Barr SC, Chang CF, Pan MJ, Chang YF. Immunogenicity and protective efficacy of recombinant Leptospira immunoglobulin-like protein B (rLigB) in a hamster challenge model. Microbes Infect 2008; 11:230-7. [PMID: 19070678 DOI: 10.1016/j.micinf.2008.11.008] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2008] [Revised: 11/10/2008] [Accepted: 11/20/2008] [Indexed: 11/29/2022]
Abstract
Leptospiral immunoglobulin-like protein (LigB) was truncated into conserved (LigBcon) and variable (varB1, varB2) fragments and expressed as GST/His-tag fusion proteins. Four-week-old hamsters were immunized with equal amounts of each fragment individually or combined in alum adjuvant at days 0 and 21 and subsequently challenged three weeks after the booster with 2.5 LD(50) live virulent Leptospira interrogans serovar Pomona. Our results demonstrate that immunization with LigB produced strong humoral immune responses as revealed by high titers against each fragment and significant enhancement in Th2 cytokines (IL-4, IL-10). A significant activation of CMI is revealed by enhanced proliferation of lymphocytes and up regulation of Th1 cytokines (IL-12p40, IFN-gamma) was also noted. Of the peptides studied, rLigBcon was able to impart maximum protection (71%), followed by rVarB1 (54%), whereas rVarB2 was not able to impart a significant level of protection (33%) against lethal infection as revealed by enhanced survival and reduced severity of histopathological lesions in vital organs (viz. kidney, liver, spleen) of the immunized animals. Moreover, concurrent administration of all three fragments significantly enhanced the protective efficacy of the vaccine (83%). Overall, our results clearly demonstrate that LigB has emerged as novel protective antigen that can be used in future subunit vaccines against leptospirosis.
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Affiliation(s)
- Weiwei Yan
- College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
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46
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Lin YP, Chang YF. The C-terminal variable domain of LigB from Leptospira mediates binding to fibronectin. J Vet Sci 2008; 9:133-44. [PMID: 18487934 PMCID: PMC2839090 DOI: 10.4142/jvs.2008.9.2.133] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Adhesion through microbial surface components that recognize adhesive matrix molecules is an essential step in infection for most pathogenic bacteria. In this study, we report that LigB interacts with fibronectin (Fn) through its variable region. A possible role for LigB in bacterial attachment to host cells during the course of infection is supported by the following observations: (i) binding of the variable region of LigB to Madin-Darby canine kidney (MDCK) cells in a dose-dependent manner reduces the adhesion of Leptospira, (ii) inhibition of leptospiral attachment to Fn by the variable region of LigB, and (iii) decrease in binding of the variable region of LigB to the MDCK cells in the presence of Fn. Furthermore, we found a significant reduction in binding of the variable region of LigB to Fn using small interfering RNA (siRNA). Finally, the isothermal titration calorimetric results confirmed the interaction between the variable region of LigB and Fn. This is the first report to demonstrate that LigB binds to MDCK cells. In addition, the reduction of Fn expression in the MDCK cells, by siRNA, reduced the binding of LigB. Taken together, the data from the present study showed that LigB is a Fn-binding protein of pathogenic Leptospira spp. and may play a pivotal role in Leptospira-host interaction during the initial stage of infection.
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Affiliation(s)
- Yi-Pin Lin
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
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47
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Evaluation of leptospiral recombinant antigens MPL17 and MPL21 for serological diagnosis of leptospirosis by enzyme-linked immunosorbent assays. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2008; 15:1715-22. [PMID: 18799647 DOI: 10.1128/cvi.00214-08] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Leptospirosis is a zoonosis of multisystem involvement caused by pathogenic strains of the genus Leptospira. In the last few years, intensive studies aimed at the development of a vaccine have provided important knowledge about the nature of the immunological mechanisms of the host. The purpose of this study was to analyze the immune responses to two recombinant proteins, MPL17 and MPL21 (encoded by the genes LIC10765 and LIC13131, respectively) of Leptospira interrogans serovar Copenhageni in individuals during infection. The recombinant proteins were expressed in Escherichia coli as six-His tag fusion proteins and were purified from the soluble bacterial fraction by affinity chromatography with Ni(2+)-charged resin. The recombinant proteins were used to evaluate their ability to bind to immunoglobulin G (IgG) (and IgG subclass) or IgM antibodies in serum samples from patients in the early and convalescent phases of leptospirosis (n = 52) by enzyme-linked immunosorbent assays. The prevalences of total IgG antibodies against MPL17 and MPL21 were 38.5% and 21.2%, respectively. The titers achieved with MPL17 were statistically significantly higher than those obtained by the reference microscopic agglutination test. The specificity of the assay was estimated to be 95.5% for MPL17 and 80.6% for MPL21 when serum samples from individuals with unrelated febrile diseases and control healthy donors were tested. The proteins are conserved among Leptospira strains that cause human and animal diseases. MPL17 and MPL21 are most likely new surface proteins of leptospires, as revealed by liquid-phase immunofluorescence assays with living organisms. Our results demonstrate that these recombinant proteins are highly immunogenic and, when they are used together, might be useful as a means of diagnosing leptospirosis.
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48
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Lin YP, Raman R, Sharma Y, Chang YF. Calcium binds to leptospiral immunoglobulin-like protein, LigB, and modulates fibronectin binding. J Biol Chem 2008; 283:25140-25149. [PMID: 18625711 DOI: 10.1074/jbc.m801350200] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Pathogenic Leptospira spp. express immunoglobulin-like proteins, LigA and LigB, which serve as adhesins to bind to extracellular matrices and mediate their attachment on host cells. However, nothing is known about the mechanism by which these proteins are involved in pathogenesis. We demonstrate that LigBCen2 binds Ca(2+), as evidenced by inductively coupled plasma optical emission spectrometry, energy dispersive spectrometry, (45)Ca overlay, and mass spectrometry, although there is no known motif for Ca(2+) binding. LigBCen2 binds four Ca(2+) as determined by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. The dissociation constant, K(D), for Ca(2+) binding is 7 mum, as measured by isothermal titration calorimetry and calcium competition experiments. The nature of the Ca(2+)-binding site in LigB is possibly similar to that seen in the betagamma-crystallin superfamily, since structurally, both families of proteins possess the Greek key type fold. The conformation of LigBCen2 was significantly influenced by Ca(2+) binding as shown by far- and near-UV CD and by fluorescence spectroscopy. In the apo form, the protein appears to be partially unfolded, as seen in the far-UV CD spectrum, and upon Ca(2+) binding, the protein acquires significant beta-sheet conformation. Ca(2+) binding stabilizes the protein as monitored by thermal unfolding by CD (50.7-54.8 degrees C) and by differential scanning calorimetry (50.0-55.7 degrees C). Ca(2+) significantly assists the binding of LigBCen2 to the N-terminal domain of fibronectin and perturbs the secondary structure, suggesting the involvement of Ca(2+) in adhesion. We demonstrate that LigB is a novel bacterial Ca(2+)-binding protein and suggest that Ca(2+) binding plays a pivotal role in the pathogenesis of leptospirosis.
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Affiliation(s)
- Yi-Pin Lin
- College of Veterinary Medicine, Cornell University, Ithaca, New York 14853 and the
| | - Rajeev Raman
- Centre for Cellular and Molecular Biology (Council of Scientific and Industrial Research), Uppal Road, Hyderabad 500 007, India
| | - Yogendra Sharma
- Centre for Cellular and Molecular Biology (Council of Scientific and Industrial Research), Uppal Road, Hyderabad 500 007, India
| | - Yung-Fu Chang
- College of Veterinary Medicine, Cornell University, Ithaca, New York 14853 and the.
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LruA and LruB antibodies in sera of humans with leptospiral uveitis. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2008; 15:1019-23. [PMID: 18400972 DOI: 10.1128/cvi.00203-07] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Uveitis can be a serious complication of leptospirosis. Previous studies indicated that the leptospiral lipoproteins LruA and LruB are expressed in the eyes of uveitic horses and that antibodies directed against those proteins show in vitro cross-reactivity with components of equine lens, ciliary body, and/or retina. We now demonstrate that sera from a significant proportion of humans who have leptospiral uveitis also contain antibodies against LruA and LruB. Different categories of nonleptospiral uveitis and autoimmune uveitis were also screened; patients diagnosed with Fuchs uveitis or Behçet's syndrome produced antibodies that cross-reacted with LruA and LruB, suggesting similarities of the autoimmune responses in those diseases with those of leptospiral uveitis.
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Faisal SM, Yan W, Chen CS, Palaniappan RUM, McDonough SP, Chang YF. Evaluation of protective immunity of Leptospira immunoglobulin like protein A (LigA) DNA vaccine against challenge in hamsters. Vaccine 2007; 26:277-87. [PMID: 18055070 DOI: 10.1016/j.vaccine.2007.10.029] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2007] [Revised: 10/07/2007] [Accepted: 10/15/2007] [Indexed: 10/22/2022]
Abstract
We demonstrated earlier that immunization with recombinant Leptospira immunoglobulin like protein A (LigA) induced significant protection against virulent Leptospira interrogans serovar Pomona challenge in hamsters. However, the protective immune mechanism remains unclear. In the present study we demonstrated the protective efficacy of a LigA DNA vaccine and evaluated the immune mechanism underlying the protection against leptospirosis in hamsters. The LigA DNA vaccine was constructed in two truncated forms as the conserved portion (LigAcon) and a variable portion (LigAvar). Four-week-old hamsters were immunized three times at two-week intervals with vector alone or an equal amount of a recombinant construct containing either LigAcon or LigAvar. All animals were challenged intraperitoneally 2 weeks after the last immunization with a dose (LD50=10(8)) of virulent L. interrogans serovar Pomona. Prior to challenge, four animals were sacrificed, the spleen was removed aseptically, and splenocytes were assayed for lymphocyte proliferation and cytokine profiles in response to recall antigen. The protective efficacy was evaluated on the basis of survival and histopathological lesions in the kidney. The immuno-protective mechanism was assessed on the basis of Th1/Th2 profile of cytokines in immunized animals. Our results indicate that immunization with LigA DNA vaccine provides significant protection against leptospirosis. We suggest that immuno-protection is conferred by both humoral and cellular immunity as revealed by an increase in antibody titers during subsequent boosters, significant proliferation of lymphocytes and enhancement of both Th1 and Th2 cytokines. Taken together, the present study suggests that a LigA DNA vaccine is a promising candidate for prevention of leptospirosis.
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Affiliation(s)
- Syed M Faisal
- College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
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