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Lopes-Luz L, Saavedra DP, Fogaça MBT, Bührer-Sékula S, Stefani MMDA. Challenges and advances in serological and molecular tests to aid leprosy diagnosis. Exp Biol Med (Maywood) 2023; 248:2083-2094. [PMID: 38059475 PMCID: PMC10800132 DOI: 10.1177/15353702231209422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2023] Open
Abstract
Leprosy is a neglected chronic infectious disease caused by obligate intracellular bacilli, Mycobacterium leprae and Mycobacterium lepromatosis. Despite multidrug therapy (MDT) success, leprosy accounts for more than 200,000 new cases yearly. Leprosy diagnosis remains based on the dermato-neurologic examination, but histopathology of skin biopsy and bacilloscopy of intradermal scraping are subsidiary diagnostic tests that require expertise and laboratory infrastructure. This minireview summarizes the state of the art of serologic tests to aid leprosy diagnosis, highlighting enzyme-linked immunosorbent assay (ELISA) and point-of-care tests (POCT) biotechnologies. Also, the impact of the postgenomic era on the description of new recombinantly expressed M. leprae-specific protein antigens, such as leprosy Infectious Disease Research Institute (IDRI) diagnostic (LID)-1 is summarized. Highly specific and sensitive molecular techniques to detect M. leprae DNA as the quantitative polymerase chain reaction (qPCR) and the loop-mediated isothermal amplification (LAMP) are briefly reviewed. Serology studies using phenolic glycolipid-I (PGL-I) semi-synthetic antigens, LID-1 fusion antigen, and the single fusion complex natural disaccharide-octyl (NDO)-LID show high sensitivity in multibacillary (MB) patients. However, serology is not applicable to paucibacillary patients, as they have weak humoral response and robust cell-mediated response, requiring tests for cellular biomarkers. Unlike ELISA-based tests, leprosy-specific POCT based on semi-synthetic PGL-I antigens and NDO-LID 1 antigen is easy to perform, cheaper, equipment-free, and can contribute to early diagnosis avoiding permanent incapacities and helping to interrupt M. leprae transmission. Besides its use to help diagnosis of household contacts or at-risk populations in endemic areas, potential applications of leprosy serology include monitoring MDT efficacy, identification of recent infection, especially in young children, as surrogate markers of disease progression to orient adult chemoprophylaxis and as a predictor of type 2 leprosy reactions. Advances in molecular biology techniques have reduced the complexity and execution time of qPCR confirming its utility to help diagnosis while leprosy-specific LAMP holds promise as an adjunct test to detect M. leprae DNA.
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Affiliation(s)
- Leonardo Lopes-Luz
- Laboratório de Desenvolvimento e Produção de Testes Rápidos, Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia 74605-050, Brasil
- Innovation Hub in Point of Care Technologies, UFG-Merck S/A. Alliance, Goiânia 74690-900, Brasil
| | - Djairo Pastor Saavedra
- Laboratório de Desenvolvimento e Produção de Testes Rápidos, Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia 74605-050, Brasil
- Innovation Hub in Point of Care Technologies, UFG-Merck S/A. Alliance, Goiânia 74690-900, Brasil
| | - Matheus Bernardes Torres Fogaça
- Laboratório de Desenvolvimento e Produção de Testes Rápidos, Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia 74605-050, Brasil
- Innovation Hub in Point of Care Technologies, UFG-Merck S/A. Alliance, Goiânia 74690-900, Brasil
| | - Samira Bührer-Sékula
- Laboratório de Desenvolvimento e Produção de Testes Rápidos, Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia 74605-050, Brasil
- Innovation Hub in Point of Care Technologies, UFG-Merck S/A. Alliance, Goiânia 74690-900, Brasil
| | - Mariane Martins de Araújo Stefani
- Laboratório de Desenvolvimento e Produção de Testes Rápidos, Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia 74605-050, Brasil
- Innovation Hub in Point of Care Technologies, UFG-Merck S/A. Alliance, Goiânia 74690-900, Brasil
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Lima MIS, Corrêa MBC, Moraes ECDS, Oliveira JDDD, de Souza Santos P, de Souza AG, Goulart IMB, Goulart LR. HSP60 mimetic peptides from Mycobacterium leprae as new antigens for immunodiagnosis of Leprosy. AMB Express 2023; 13:120. [PMID: 37891336 PMCID: PMC10611693 DOI: 10.1186/s13568-023-01625-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 10/09/2023] [Indexed: 10/29/2023] Open
Abstract
The early diagnosis of leprosy serves as an important tool to reduce the incidence of this disease in the world. Phage display (PD) technology can be used for mapping new antigens to the development of immunodiagnostic platforms. Our objective was to identify peptides that mimic Mycobacterium leprae proteins as serological markers using phage display technology. The phages were obtained in the biopanning using negative and positive serum from household contacts and leprosy patients, respectively. Then, the peptides were synthesized and validated in silico and in vitro for detection of IgG from patients and contacts. To characterize the native protein of M. leprae, scFv antibodies were selected against the synthetic peptides by PD. The scFv binding protein was obtained by immunocapture and confirmed using mass spectrometry. We selected two phase-fused peptides, MPML12 and MPML14, which mimic the HSP60 protein from M. leprae. The peptides MPML12 and MPML14 obtained 100% and 92.85% positivity in lepromatous patients. MPML12 and MPM14 detect IgG, especially in the multibacillary forms. The MPML12 and MPML14 peptides had positivity of 11.1% and 16.6% in household contacts, respectively. There was no cross-reaction in patient's samples with visceral leishmaniasis, tuberculosis and other mycobacteriosis for both peptides. Given these results and the easy obtainment of mimetic antigens, our peptides are promising markers for application in the diagnosis of leprosy, especially in endemic and hyperendemic regions.
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Affiliation(s)
- Mayara Ingrid Sousa Lima
- Laboratory of Genetics and Molecular Biology, Department of Biology, Federal University of Maranhão, São Luís, MA, Brazil.
- Postgraduate Program on Health and Environment and Postgraduate Program on Health Sciences, Federal University of Maranhão, São Luís, MA, Brazil.
| | | | | | | | - Paula de Souza Santos
- Institute of Biotechnology, Federal University of Uberlandia, Uberlandia, MG, Brazil
| | - Aline Gomes de Souza
- Institute of Biotechnology, Federal University of Uberlandia, Uberlandia, MG, Brazil
| | - Isabela Maria Bernardes Goulart
- National Reference Center in Sanitary Dermatology and Leprosy, School of Medicine, Clinics' Hospital, Federal University of Uberlandia, Uberlandia, MG, Brazil.
| | - Luiz Ricardo Goulart
- Institute of Biotechnology, Federal University of Uberlandia, Uberlandia, MG, Brazil
- Department of Medical Microbiology and Immunology, University of California, Davis, CA, USA
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van Hooij A, Geluk A. In search of biomarkers for leprosy by unraveling the host immune response to Mycobacterium leprae. Immunol Rev 2021; 301:175-192. [PMID: 33709405 PMCID: PMC8251784 DOI: 10.1111/imr.12966] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 02/23/2021] [Indexed: 12/18/2022]
Abstract
Mycobacterium leprae, the causative agent of leprosy, is still actively transmitted in endemic areas reflected by the fairly stable number of new cases detected each year. Recognizing the signs and symptoms of leprosy is challenging, especially at an early stage. Improved diagnostic tools, based on sensitive and specific biomarkers, that facilitate diagnosis of leprosy are therefore urgently needed. In this review, we address the challenges that leprosy biomarker research is facing by reviewing cell types reported to be involved in host immunity to M leprae. These cell types can be associated with different possible fates of M leprae infection being either protective immunity, or pathogenic immune responses inducing nerve damage. Unraveling these responses will facilitate the search for biomarkers. Implications for further studies to disentangle the complex interplay between host responses that lead to leprosy disease are discussed, providing leads for the identification of new biomarkers to improve leprosy diagnostics.
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Affiliation(s)
- Anouk van Hooij
- Department of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
| | - Annemieke Geluk
- Department of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
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Sensitivity and specificity of multibacillary and paucibacillary leprosy laboratory tests: A systematic review and meta-analysis. Diagn Microbiol Infect Dis 2021; 100:115337. [PMID: 33610964 DOI: 10.1016/j.diagmicrobio.2021.115337] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 01/20/2021] [Accepted: 01/30/2021] [Indexed: 12/11/2022]
Abstract
This systematic review (number register: CRD42018112736) was performed to compare the sensitivity and specificity of leprosy diagnostic methods. The search was conducted in 3 electronic databases in January 2021. Studies evaluating leprosy diagnostic tests were included according the eligibility criteria. Meta-analysis was performed to calculate the sensibility and specificity of the groups. We included 36 studies. The test sensitivity for paucibacillary patients was 0.31 (95%CI: 0.29-0.33) and the specificity was 0.92 (95%CI: 0.92-0.93). In multibacillary patients, the sensitivity was 0.78 (95%CI: 0.77-0.80) and specificity was 0.92 (95%CI: 0.92-0.93). Comparing the sensitivity and specificity of the different techniques included, it should be noted that polymerase chain reaction (PCR) test presented the highest sensitivity for paucibacillary patients, while the western blot technique showed the highest sensitivity for multibacillary patients. However, further studies are needed to optimise the diagnosis of leprosy, requiring research with a larger number of samples and more uniform protocols.
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Gama RS, Leite LA, Colombo LT, Fraga LADO. Prospects for new leprosy diagnostic tools, a narrative review considering ELISA and PCR assays. Rev Soc Bras Med Trop 2020; 53:e20200197. [PMID: 33263683 PMCID: PMC7723377 DOI: 10.1590/0037-8682-0197-2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 10/26/2020] [Indexed: 11/21/2022] Open
Abstract
Slit skin smear and histopathological examinations are currently the main laboratory tools used to aid the diagnosis of leprosy. However, their sensitivity is low, and many cases are not detected. New methodologies have been studied to develop more accurate tests. This narrative review aims to raise attention to the results of molecular (polymerase chain reaction) and serological (Enzyme-Linked Immunosorbent Assay) tests applied to the diagnosis of leprosy, and to summarize the available information about the former. Original scientific articles published in indexed international journals, whose study involved aspects of the diagnosis and classification of leprosy cases or home contacts, were selected. The data were extracted independently using a standardized method that dictated the inclusion of the following information: diagnosis in Paucibacillary and Multibacillary cases and in household contacts; sample number; sample type; study design; studied variables; statistical analysis employed; main results; and limitations identified. In clinical practice, the results from molecular and serological tests are assessed separately, with moderate sensitivity and specificity. However, an integrated study of these methodologies has been suggested for greater accuracy in diagnosis.
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Affiliation(s)
- Rafael Silva Gama
- Universidade Vale do Rio Doce, Laboratório de Biologia Molecular, Governador Valadares, MG, Brasil
| | - Lázaro Azevedo Leite
- Universidade Vale do Rio Doce, Laboratório de Biologia Molecular, Governador Valadares, MG, Brasil
| | - Lívia Tavares Colombo
- Universidade Vale do Rio Doce, Laboratório de Biologia Molecular, Governador Valadares, MG, Brasil
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Carvalho JCD, Araújo MG, Coelho-Dos-Reis JGA, Peruhype-Magalhães V, Alvares CC, Moreira MDL, Teixeira-Carvalho A, Martins-Filho OA, Araújo MSS. Phenotypic and functional features of innate and adaptive immunity as putative biomarkers for clinical status and leprosy reactions. Microb Pathog 2018; 125:230-239. [PMID: 30195647 DOI: 10.1016/j.micpath.2018.09.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 07/31/2018] [Accepted: 09/05/2018] [Indexed: 12/20/2022]
Abstract
The aim of this study was to identify phenotypic and functional biomarkers associated with distinct clinical status of leprosy or leprosy reactions. The study included tuberculoid/borderline (BB/BT/T) and lepromatous (BL/L) leprosy poles as well as Type-1 and Type-2 leprosy reactions along with healthy controls (NI). A range of peripheral blood biomarkers of innate (neutrophils - NEU and monocytes - MON) and adaptive immunity (CD4+ and CD8+ T-cells) were evaluated ex vivo and upon in vitro stimuli with M. leprae antigen. Data analysis allowed the selection of NEUTLR4+ (ex vivo) and CD4+IL-10+ (in vitro) as universal biomarkers increased in all leprosy patients and those exhibiting leprosy reactions. A range of biomarkers were commonly found in both poles of leprosy patients, including decreased levels of MONTGF-β+ (ex vivo) and increased levels of MONTNF-α+, CD4+TGF-β+, CD8+TLR2+, CD8+TNF-α+, CD8+IL-4+ and CD8+TGF-β+ (in vitro). Noteworthy was that MONHLA-DR+ (ex vivo) and CD8+IL-10+ (in vitro) were particularly found in BL/L patients. Leprosy patients with Type-1 reaction exhibited a larger list of altered biomarkers, mainly involving activation markers (TLR2, TLR4, HLA-DR and DAF-2T) in NEU and MON along with CD4+ and CD8+ cells. In summary, this study provided insights about immunological features of leprosy poles and leprosy reactional episodes with putative applicability, including novel biomarkers for complementary diagnosis and future therapeutic approaches in clinical studies.
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Affiliation(s)
- Jairo Campos de Carvalho
- Grupo Integrado de Pesquisas em Biomarcadores, Instituto René Rachou/FIOCRUZ - MG, Belo Horizonte, Minas Gerais, Brazil; Fundação Hospitalar do Estado de Minas Gerais, Alameda Vereador Álvaro Celso, 100 - Santa Efigênia, Belo Horizonte, Minas Gerais, Brazil.
| | - Marcelo Grossi Araújo
- Serviço de Dermatologia do Hospital das Clínicas da Universidade Federal de Minas Gerais, Al. Álvaro Celso, 55, Santa Efigênia, Belo Horizonte, Minas Gerais, Brazil.
| | | | - Vanessa Peruhype-Magalhães
- Grupo Integrado de Pesquisas em Biomarcadores, Instituto René Rachou/FIOCRUZ - MG, Belo Horizonte, Minas Gerais, Brazil.
| | - Cláudio Caetano Alvares
- Grupo Integrado de Pesquisas em Biomarcadores, Instituto René Rachou/FIOCRUZ - MG, Belo Horizonte, Minas Gerais, Brazil.
| | - Marcela de Lima Moreira
- Grupo Integrado de Pesquisas em Biomarcadores, Instituto René Rachou/FIOCRUZ - MG, Belo Horizonte, Minas Gerais, Brazil.
| | - Andréa Teixeira-Carvalho
- Grupo Integrado de Pesquisas em Biomarcadores, Instituto René Rachou/FIOCRUZ - MG, Belo Horizonte, Minas Gerais, Brazil.
| | - Olindo Assis Martins-Filho
- Grupo Integrado de Pesquisas em Biomarcadores, Instituto René Rachou/FIOCRUZ - MG, Belo Horizonte, Minas Gerais, Brazil.
| | - Márcio Sobreira Silva Araújo
- Grupo Integrado de Pesquisas em Biomarcadores, Instituto René Rachou/FIOCRUZ - MG, Belo Horizonte, Minas Gerais, Brazil.
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Antigen-specific secretion of IFNγ and CXCL10 in whole blood assay detects Mycobacterium leprae infection but does not discriminate asymptomatic infection from symptomatic leprosy. Diagn Microbiol Infect Dis 2017; 87:328-334. [DOI: 10.1016/j.diagmicrobio.2017.01.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 12/20/2016] [Accepted: 01/03/2017] [Indexed: 11/24/2022]
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Rana A, Thakur S, Bhardwaj N, Kumar D, Akhter Y. Excavating the surface-associated and secretory proteome of Mycobacterium leprae for identifying vaccines and diagnostic markers relevant immunodominant epitopes. Pathog Dis 2016; 74:ftw110. [PMID: 27856491 DOI: 10.1093/femspd/ftw110] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 06/13/2016] [Accepted: 11/13/2016] [Indexed: 02/03/2023] Open
Abstract
For centuries, Mycobacterium leprae, etiological agent of leprosy, has been afflicting mankind regardless of extensive use of live-attenuated vaccines and antibiotics. Surface-associated and secretory proteins (SASPs) are attractive targets against bacteria. We have integrated biological knowledge with computational approaches and present a proteome-wide identification of SASPs. We also performed computational assignment of immunodominant epitopes as coordinates of prospective antigenic candidates in most important class of SASPs, the outer membrane proteins (OMPs). Exploiting the known protein sequence and structural characteristics shared by the SASPs from bacteria, 17 lipoproteins, 11 secretory and 19 novel OMPs (including 4 essential proteins) were identified in M. leprae As OMPs represent the most exposed antigens on the cell surface, their immunoinformatics analysis showed that the identified 19 OMPs harbor T-cell MHC class I epitopes and class II epitopes against HLA-DR alleles (54), while 15 OMPs present potential T-cell class II epitopes against HLA-DQ alleles (6) and 7 OMPs possess T-cell class II epitopes against HLA-DP alleles (5) of humans. Additionally, 11 M. leprae OMPs were found to have B-cell epitopes and these may be considered as prime candidates for the development of new immunotherapeutics against M. leprae.
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Affiliation(s)
- Aarti Rana
- School of Life Sciences, Central University of Himachal Pradesh, Shahpur, District-Kangra, Himachal Pradesh-176206, India
| | - Shweta Thakur
- School of Life Sciences, Central University of Himachal Pradesh, Shahpur, District-Kangra, Himachal Pradesh-176206, India
| | - Nupur Bhardwaj
- School of Life Sciences, Central University of Himachal Pradesh, Shahpur, District-Kangra, Himachal Pradesh-176206, India
| | - Devender Kumar
- School of Life Sciences, Central University of Himachal Pradesh, Shahpur, District-Kangra, Himachal Pradesh-176206, India
| | - Yusuf Akhter
- School of Life Sciences, Central University of Himachal Pradesh, Shahpur, District-Kangra, Himachal Pradesh-176206, India
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Mizoguti DDF, Hungria EM, Freitas AA, Oliveira RM, Cardoso LPV, Costa MB, Sousa ALM, Duthie MS, Stefani MMA. Multibacillary leprosy patients with high and persistent serum antibodies to leprosy IDRI diagnostic-1/LID-1: higher susceptibility to develop type 2 reactions. Mem Inst Oswaldo Cruz 2016; 110:914-20. [PMID: 26560982 PMCID: PMC4660621 DOI: 10.1590/0074-02760150198] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 08/21/2015] [Indexed: 05/28/2023] Open
Abstract
Leprosy inflammatory episodes [type 1 (T1R) and type 2 (T2R) reactions] represent the major cause of irreversible nerve damage. Leprosy serology is known to be influenced by the patient's bacterial index (BI) with higher positivity in multibacillary patients (MB) and specific multidrug therapy (MDT) reduces antibody production. This study evaluated by ELISA antibody responses to leprosy Infectious Disease Research Institute diagnostic-1 (LID-1) fusion protein and phenolic glycolipid I (PGL-I) in 100 paired serum samples of 50 MB patients collected in the presence/absence of reactions and in nonreactional patients before/after MDT. Patients who presented T2R had a median BI of 3+, while MB patients with T1R and nonreactional patients had median BI of 2.5+ (p > 0.05). Anti-LID-1 and anti-PGL-I antibodies declined in patients diagnosed during T1R (p < 0.05). Anti-LID-1 levels waned in MB with T2R at diagnosis and nonreactional MB patients (p < 0.05). Higher anti-LID-1 levels were seen in patients with T2R at diagnosis (vs. patients with T1R at diagnosis, p = 0.008; vs. nonreactional patients, p = 0.020) and in patients with T2R during MDT (vs. nonreactional MB, p = 0.020). In MB patients, high and persistent anti-LID-1 antibody levels might be a useful tool for clinicians to predict which patients are more susceptible to develop leprosy T2R.
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Affiliation(s)
| | - Emerith Mayra Hungria
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, GO, Brasil
| | - Aline Araújo Freitas
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, GO, Brasil
| | | | | | - Mauricio Barcelos Costa
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, GO, Brasil
| | - Ana Lúcia Maroclo Sousa
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, GO, Brasil
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Freitas AA, Hungria EM, Costa MB, Sousa ALOM, Castilho MLO, Gonçalves HS, Pontes MAA, Duthie MS, Stefani MMA. Application of Mycobacterium Leprae-specific cellular and serological tests for the differential diagnosis of leprosy from confounding dermatoses. Diagn Microbiol Infect Dis 2016; 86:163-8. [PMID: 27506457 DOI: 10.1016/j.diagmicrobio.2016.07.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 07/13/2016] [Accepted: 07/21/2016] [Indexed: 10/21/2022]
Abstract
Mycobacterium leprae-specific serological and cell-mediated-immunity/CMI test were evaluated for the differential diagnosis of multibacillary/MB, and paucibacillary/PB leprosy from other dermatoses. Whole-blood assay/WBA/IFNγ stimulated with LID-1 antigen and ELISA tests for IgG to LID-1 and IgM to PGL-I were performed. WBA/LID-1/IFNγ production was observed in 72% PB, 11% MB leprosy, 38% dermatoses, 40% healthy endemic controls/EC. The receiver operating curve/ROC for WBA/LID-1 in PB versus other dermatoses showed 72.5% sensitivity, 61.5% specificity and an area-under-the-curve/AUC=0.75; 74% positive predictive value/PPV, 59% negative predictive value/NPV. Anti PGL-I serology was positive in 67% MB, 8% PB leprosy, 6% of other dermatoses; its sensitivity for MB=66%, specificity=93%, AUC=0.89; PPV=91%, NPV=72%. Anti-LID-1 serology was positive in 87% MB, 7% PB leprosy, all other participants were seronegative; 87.5% sensitivity for MB, 100% specificity, AUC=0.97; PPV=100%, NPV=88%. In highly endemic areas anti-LID-1/PGL-I serology and WBA/LID-1-represent useful tools for the differential diagnosis of leprosy from other confounding dermatoses.
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Affiliation(s)
- Aline Araújo Freitas
- Tropical Pathology and Public Health Institute, Federal University of Goiás, Goiânia, Brazil
| | - Emerith Mayra Hungria
- Tropical Pathology and Public Health Institute, Federal University of Goiás, Goiânia, Brazil
| | - Maurício Barcelos Costa
- Tropical Pathology and Public Health Institute, Federal University of Goiás, Goiânia, Brazil
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Hossain MU, Hashem A, Keya CA, Salimullah M. Therapeutics Insight with Inclusive Immunopharmacology Explication of Human Rotavirus A for the Treatment of Diarrhea. Front Pharmacol 2016; 7:153. [PMID: 27445802 PMCID: PMC4917548 DOI: 10.3389/fphar.2016.00153] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2016] [Accepted: 05/27/2016] [Indexed: 01/02/2023] Open
Abstract
Rotavirus is the most common cause of severe infant and childhood diarrhea worldwide, and the morbidity and mortality rate is going to be outnumbered in developing countries like Bangladesh. To mitigate this substantial burden of disease, new therapeutics such as vaccine and drug are swiftly required against rotavirus. The present therapeutics insight study was performed with comprehensive immunoinformatics and pharmacoinformatics approach. T and B-cell epitopes were assessed in the conserved region of outer capsid protein VP4 among the highly reviewed strains from different countries including Bangladesh. The results suggest that epitope SU1 (TLKNLNDNY) could be an ideal candidate among the predicted five epitopes for both T and B-cell epitopes for the development of universal vaccine against rotavirus. This research also suggests five novel drug compounds from medicinal plant Rhizophora mucronata Lamk. for better therapeutics strategies against rotavirus diarrhea based on 3D structure building, pharmacophore, ADMET, and QSAR properties. The exact mode of action between drug compounds and target protein VP4 were revealed by molecular docking analysis. Drug likeness and oral bioavailability further confirmed the effectiveness of the proposed drugs against rotavirus diarrhea. This study might be implemented for experimental validation to facilitate the novel vaccine and drug design.
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Affiliation(s)
- Mohammad Uzzal Hossain
- Department of Biotechnology and Genetic Engineering, Life Science Faculty, Mawlana Bhashani Science and Technology University Tangail, Bangladesh
| | - Abu Hashem
- Microbial Biotechnology Division, National Institute of Biotechnology Dhaka, Bangladesh
| | - Chaman Ara Keya
- Department of Biology and Chemistry, North South University Dhaka, Bangladesh
| | - Md Salimullah
- Molecular Biotechnology Division, National Institute of Biotechnology Dhaka, Bangladesh
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13
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Abstract
Leprosy, caused by noncultivable Mycobacterium leprae (ML), has varied manifestations, which are associated with the host immune responses. The dermal involvement is accompanied by peripheral nerve damage, which leads to sensory motor loss and deformities. Both innate and acquired immune responses are involved. The main cell to be compromised is the CD4 + T helper cell, which shows antigen specific unresponsiveness to only ML and not to other common antigens in the bacilliferous generalized lepromatous form of the disease. In contrast, the paucibacillary localized tuberculoid form shows appropriate T cell functions and poor antibody response. The dichotomy between T cell functions and antibodies are discussed against the current information on cytokines, Th subsets, and regulatory T cells. During lepromatous reactions, there is a temporary, heightened T cell immunity, even in lepromatous subjects. The dermal lesions confirm many features observed with peripheral blood mononuclear cells and give additional information on local immune responses. Nerve damage involves both immune and nonimmune mechanisms. Leprosy is a model disease for understanding host immune responses to intracellular bacilli. There are challenges in diagnosing early leprosy. In spite of intensive efforts by many groups, consensus on a universal test suitable for endemic areas is awaited.
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Affiliation(s)
- Indira Nath
- Institute of Pathology (ICMR), Safdarjung Hospital Campus, New Delhi, India.
| | - Chaman Saini
- Institute of Pathology (ICMR), Safdarjung Hospital Campus, New Delhi, India
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IL-10 and NOS2 modulate antigen-specific reactivity and nerve infiltration by T cells in experimental leprosy. PLoS Negl Trop Dis 2014; 8:e3149. [PMID: 25210773 PMCID: PMC4161319 DOI: 10.1371/journal.pntd.0003149] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Accepted: 07/28/2014] [Indexed: 12/18/2022] Open
Abstract
Background Although immunopathology dictates clinical outcome in leprosy, the dynamics of early and chronic infection are poorly defined. In the tuberculoid region of the spectrum, Mycobacterium leprae growth is restricted yet a severe granulomatous lesion can occur. The evolution and maintenance of chronic inflammatory processes like those observed in the leprosy granuloma involve an ongoing network of communications via cytokines. IL-10 has immunosuppressive properties and IL-10 genetic variants have been associated with leprosy development and reactions. Methodology/Principal Findings The role of IL-10 in resistance and inflammation in leprosy was investigated using Mycobacterium leprae infection of mice deficient in IL-10 (IL-10−/−), as well as mice deficient in both inducible nitric oxide synthase (NOS2−/−) and IL-10 (10NOS2−/−). Although a lack of IL-10 did not affect M. leprae multiplication in the footpads (FP), inflammation increased from C57Bl/6 (B6)<IL-10−/−<NOS2−/−<10NOS2−/−. While IL-10−/− mice exhibited modest FP induration compared to B6, NOS2−/− and 10NOS2−/− mice developed markedly enlarged FP marking distinct phases: early (1 month), peak (3–4 months), and chronic (8 months). IFN-γ-producing CD4+CD44+ cells responding to M. leprae cell wall, membrane, and cytosol antigens and ML2028 (Ag85B) were significantly increased in the evolved granuloma in NOS2−/− FP compared to B6 and IL-10−/− during early and peak phases. In 10NOS2−/− FP, CD4+CD44+ and especially CD8+CD44+ responses were augmented even further to these antigens as well as to ML0380 (GroES), ML2038 (bacterioferritin), and ML1877 (EF-Tu). Moreover, fragmented nerves containing CD4+ cells were present in 10NOS2−/− FP. Conclusions/Significance The 10NOS2−/− strain offers insight on the regulation of granuloma formation and maintenance by immune modulators in the resistant forms of leprosy and presents a new model for investigating the pathogenesis of neurological involvement. Despite effective antimicrobial therapy, 30–50% of leprosy patients develop immunological complications called leprosy reactions before, during or even years after being cured. Leprosy reactions are a major risk for neuritis that leads to peripheral nerve damage, disfigurement and disability. Unfortunately, why and how leprosy reactions occur is not well understood. Based on the latest human genetic leprosy susceptibility research and mouse infection models, we generated a double knockout mouse strain (10NOS2−/−) which has deficiencies in two key immune factors, interleukin-10 (IL-10) and inducible nitric oxide synthase (NOS2). We investigated the dynamics of the immune response to Mycobacterium leprae infection and chronicled the types of immune cells recruited to the site of infection. 10NOS2−/− mice developed a substantial induration in response to infection, as well as an increased interferon-gamma response to components of the leprosy bacillus. Interestingly, these animals also exhibited CD4+ T cell infiltration into the nerves, a phenomenon which has not been previously reported in leprosy mouse models. This new model provides insight into potential mechanisms whereby immune modulators may regulate leprosy reactions and neuritis and could aid the development of tests for monitoring and treatment of leprosy patients.
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Phage display and synthetic peptides as promising biotechnological tools for the serological diagnosis of leprosy. PLoS One 2014; 9:e106222. [PMID: 25170947 PMCID: PMC4149539 DOI: 10.1371/journal.pone.0106222] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 07/30/2014] [Indexed: 11/22/2022] Open
Abstract
Background The diagnosis of leprosy is primarily based on clinical manifestations, and there is no widely available laboratory test for the early detection of this disease, which is caused by Mycobacterium leprae. In fact, early detection and treatment are the key elements to the successful control of leprosy. Methodology/Principal Findings Peptide ligands for antibodies from leprosy patients were selected from phage-displayed peptide libraries. Three peptide sequences expressed by reactive phage clones were chemically synthesized. Serological assays that used synthetic peptides were evaluated using serum samples from leprosy patients, household contacts (HC) of leprosy patients, tuberculosis patients and endemic controls (EC). A pool of three peptides identified 73.9% (17/23) of multibacillary (MB) leprosy patients using an enzyme-linked immunosorbent assay (ELISA). These peptides also showed some seroreactivities to the HC and EC individuals. The peptides were not reactive to rabbit polyclonal antisera against the different environmental mycobacteria. The same peptides that were conjugated to the carrier protein bovine serum albumin (BSA) induced the production of antibodies in the mice. The anti-peptide antibodies that were used in the Western blotting analysis of M. leprae crude extracts revealed a single band of approximately 30 kDa in one-dimensional electrophoresis and four 30 kDa isoforms in the two-dimensional gel. The Western blotting data indicated that the three peptides are derived from the same bacterial protein. Conclusions/Significance These new antigens may be useful in the diagnosis of MB leprosy patients. Their potentials as diagnostic reagents must be more extensively evaluated in future studies using a large panel of positive and negative sera. Furthermore, other test approaches using peptides should be assessed to increase their sensitivity and specificity in detecting leprosy patients. We have revealed evidence in support of phage-displayed peptides as promising biotechnological tools for the design of leprosy diagnostic serological assays.
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Analysis of antigens of Mycobacterium leprae by interaction to sera IgG, IgM, and IgA response to improve diagnosis of leprosy. BIOMED RESEARCH INTERNATIONAL 2014; 2014:283278. [PMID: 25101267 PMCID: PMC4102069 DOI: 10.1155/2014/283278] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 05/21/2014] [Accepted: 06/09/2014] [Indexed: 02/08/2023]
Abstract
Till 2010, several countries have declared less than one leprosy patient among population of 10,000 and themselves feeling as eliminated from leprosy cases. However, new leprosy cases are still appearing from all these countries. In this situation one has to be confident to diagnose leprosy. This review paper highlighted already explored antigens for diagnosis purposes and finally suggested better combinations of protein antigens of M. leprae versus immunoglobulin as detector antibody to be useful for leprosy diagnosis.
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Oliveira RM, Hungria EM, de Araújo Freitas A, de Sousa ALOM, Costa MB, Reed SG, Duthie MS, Stefani MMA. Synergistic antigen combinations for the development of interferon gamma release assays for paucibacillary leprosy. Eur J Clin Microbiol Infect Dis 2014; 33:1415-24. [DOI: 10.1007/s10096-014-2077-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Accepted: 01/31/2014] [Indexed: 02/07/2023]
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Bobosha K, Tang ST, van der Ploeg-van Schip JJ, Bekele Y, Martins MVSB, Lund O, Franken KLMC, Khadge S, Pontes MADA, Gonçalves HDS, Hussien J, Thapa P, Kunwar CB, Hagge DA, Aseffa A, Pessolani MCV, Pereira GMB, Ottenhoff THM, Geluk A. Mycobacterium leprae virulence-associated peptides are indicators of exposure to M. leprae in Brazil, Ethiopia and Nepal. Mem Inst Oswaldo Cruz 2013; 107 Suppl 1:112-23. [PMID: 23283462 DOI: 10.1590/s0074-02762012000900018] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Accepted: 07/03/2012] [Indexed: 12/13/2022] Open
Abstract
Silent transmission of Mycobacterium leprae, as evidenced by stable leprosy incidence rates in various countries, remains a health challenge despite the implementation of multidrug therapy worldwide. Therefore, the development of tools for the early diagnosis of M. leprae infection should be emphasised in leprosy research. As part of the continuing effort to identify antigens that have diagnostic potential, unique M. leprae peptides derived from predicted virulence-associated proteins (group IV.A) were identified using advanced genome pattern programs and bioinformatics. Based on human leukocyte antigen (HLA)-binding motifs, we selected 21 peptides that were predicted to be promiscuous HLA-class I T-cell epitopes and eight peptides that were predicted to be HLA-class II restricted T-cell epitopes for field-testing in Brazil, Ethiopia and Nepal. High levels of interferon (IFN)-γ were induced when peripheral blood mononuclear cells (PBMCs) from tuberculoid/borderline tuberculoid leprosy patients located in Brazil and Ethiopia were stimulated with the ML2055 p35 peptide. PBMCs that were isolated from healthy endemic controls living in areas with high leprosy prevalence (EChigh) in Ethiopia also responded to the ML2055 p35 peptide. The Brazilian EChigh group recognised the ML1358 p20 and ML1358 p24 peptides. None of the peptides were recognised by PBMCs from healthy controls living in non-endemic region. In Nepal, mixtures of these peptides induced the production of IFN-γ by the PBMCs of leprosy patients and EChigh. Therefore, the M. leprae virulence-associated peptides identified in this study may be useful for identifying exposure to M. leprae in population with differing HLA polymorphisms.
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Affiliation(s)
- Kidist Bobosha
- Department of Infectious Diseases, University Medical Center, Leiden, The Netherlands
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Anusuya S, Natarajan J. The eradication of leprosy: molecular modeling techniques for novel drug discovery. Expert Opin Drug Discov 2013; 8:1239-51. [PMID: 23924296 DOI: 10.1517/17460441.2013.826188] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Leprosy is a slowly progressing bacterial infection caused by Mycobacterium leprae. The World Health Organization recommended multidrug therapy (MDT) which is extremely effective and halts the progress of the disease. Even though the objective of eliminating leprosy as a public health problem has been achieved successfully, leprosy is not yet eradicated. Furthermore, the long-term use of MDT results in single- and multidrug resistance. Therefore, there is still a need for new drug discovery for leprosy. AREAS COVERED The authors explain the importance of discovery of new drug to leprosy and the significance of homology modeling to drug discovery. This review highlights the principle steps, applications, and the resources of homology modeling. Finally, the authors emphasize the application of different structure-based drug design (SBDD) approaches to design novel therapeutics for leprosy. EXPERT OPINION MDT has proved to be effective in controlling infection, with prevalence of leprosy now predominantly isolated to the developing countries. The emergence of single- and multidrug-resistant strains of M. leprae has, however, provided some concern with the need for newer antibacterial agents. Drug resistance can be overcome by multi-targeted therapy. SBDD approaches, which reported many successful drugs, depend predominantly on the three-dimensional (3D) structure of drug targets. As of 2013, only very few experimental structures are available for M. leprae proteins. Hence, SBDD, in leprosy research, relies heavily on homology modeling to predict the 3D structure of drug targets and to design better therapeutics.
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Affiliation(s)
- Shanmugam Anusuya
- V.M.K.V. Engineering College, Department of Bioinformatics , Salem 636308, Tamil Nadu , India
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Gene expression profile and immunological evaluation of unique hypothetical unknown proteins of Mycobacterium leprae by using quantitative real-time PCR. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2012; 20:181-90. [PMID: 23239802 DOI: 10.1128/cvi.00419-12] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The cell-mediated immunity (CMI)-based in vitro gamma interferon release assay (IGRA) of Mycobacterium leprae-specific antigens has potential as a promising diagnostic means to detect those individuals in the early stages of M. leprae infection. Diagnosis of leprosy is a major obstacle toward ultimate disease control and has been compromised in the past by the lack of specific markers. Comparative bioinformatic analysis among mycobacterial genomes identified potential M. leprae-specific proteins called "hypothetical unknowns." Due to massive gene decay and the prevalence of pseudogenes, it is unclear whether any of these proteins are expressed or are immunologically relevant. In this study, we performed cDNA-based quantitative real-time PCR to investigate the expression status of 131 putative open reading frames (ORFs) encoding hypothetical unknowns. Twenty-six of the M. leprae-specific antigen candidates showed significant levels of gene expression compared to that of ESAT-6 (ML0049), which is an important T cell antigen of low abundance in M. leprae. Fifteen of 26 selected antigen candidates were expressed and purified in Escherichia coli. The seroreactivity to these proteins of pooled sera from lepromatous leprosy patients and cavitary tuberculosis patients revealed that 9 of 15 recombinant hypothetical unknowns elicited M. leprae-specific immune responses. These nine proteins may be good diagnostic reagents to improve both the sensitivity and specificity of detection of individuals with asymptomatic leprosy.
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Duthie MS, Sampaio LH, Oliveira RM, Raman VS, O'Donnell J, Bailor HR, Ireton GC, Sousa ALM, Stefani MMA, Reed SG. Development and pre-clinical assessment of a 73 kD chimeric fusion protein as a defined sub-unit vaccine for leprosy. Vaccine 2012; 31:813-9. [PMID: 23228811 DOI: 10.1016/j.vaccine.2012.11.073] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Revised: 11/21/2012] [Accepted: 11/24/2012] [Indexed: 12/01/2022]
Abstract
Despite the advances toward the elimination of leprosy through widespread provision of multi-drug therapy to registered patients over the last 2 decades, new case detection rates have stabilized and leprosy remains endemic in a number of localized regions. A vaccine could overcome the inherent limitations of the drug treatment program by providing protection in individuals who are not already harboring the Mycobacterium leprae bacilli at the time of administration and effectively interrupt the transmission cycle over a wider timespan. In this report we present data validating the production of 73f, a chimeric fusion protein incorporating the M. leprae antigens ML2028, ML2346 and ML2044. The 73f protein was recognized by IgG in multibacillary (MB) leprosy patient sera and stimulated IFNγ production within whole blood assays of paucibacillary (PB) leprosy patient and healthy household contacts of MB patients (HHC). When formulated with a TLR4L-containing adjuvant (GLA-SE), 73f stimulated a strong and pluripotent Th1 response that inhibited M. leprae-induced inflammation in mice. We are using these data to develop new vaccine initiatives for the continued and long-term control of leprosy.
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Hungria EM, Oliveira RMD, Souza ALOMD, Costa MB, Souza VNBD, Silva EA, Moreno FRV, Nogueira MES, Costa MRSN, Silva SMUR, Bührer-Sékula S, Reed SG, Duthie MS, Stefani MMDA. Seroreactivity to new Mycobacterium leprae protein antigens in different leprosy-endemic regions in Brazil. Mem Inst Oswaldo Cruz 2012; 107 Suppl 1:104-11. [DOI: 10.1590/s0074-02762012000900017] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Accepted: 07/25/2012] [Indexed: 11/22/2022] Open
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Martins MVSB, Guimarães MMDS, Spencer JS, Hacker MAVB, Costa LS, Carvalho FM, Geluk A, van der Ploeg-van Schip JJ, Pontes MAA, Gonçalves HS, de Morais JP, Bandeira TJPG, Pessolani MCV, Brennan PJ, Pereira GMB. Pathogen-specific epitopes as epidemiological tools for defining the magnitude of Mycobacterium leprae transmission in areas endemic for leprosy. PLoS Negl Trop Dis 2012; 6:e1616. [PMID: 22545169 PMCID: PMC3335884 DOI: 10.1371/journal.pntd.0001616] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Accepted: 03/05/2012] [Indexed: 11/19/2022] Open
Abstract
During recent years, comparative genomic analysis has allowed the identification of Mycobacterium leprae-specific genes with potential application for the diagnosis of leprosy. In a previous study, 58 synthetic peptides derived from these sequences were tested for their ability to induce production of IFN-γ in PBMC from endemic controls (EC) with unknown exposure to M. leprae, household contacts of leprosy patients and patients, indicating the potential of these synthetic peptides for the diagnosis of sub- or preclinical forms of leprosy. In the present study, the patterns of IFN-γ release of the individuals exposed or non-exposed to M. leprae were compared using an Artificial Neural Network algorithm, and the most promising M. leprae peptides for the identification of exposed people were selected. This subset of M. leprae-specific peptides allowed the differentiation of groups of individuals from sites hyperendemic for leprosy versus those from areas with lower level detection rates. A progressive reduction in the IFN-γ levels in response to the peptides was seen when contacts of multibacillary (MB) patients were compared to other less exposed groups, suggesting a down modulation of IFN-γ production with an increase in bacillary load or exposure to M. leprae. The data generated indicate that an IFN-γ assay based on these peptides applied individually or as a pool can be used as a new tool for predicting the magnitude of M. leprae transmission in a given population.
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Affiliation(s)
- Marcia V. S. B. Martins
- Laboratory of Cellular Microbiology, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, Brazil
| | | | - John S. Spencer
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | | | - Luciana S. Costa
- Laboratory of Medical Informatics, School of Medical Sciences, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Fernanda M. Carvalho
- Laboratory of Cellular Microbiology, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, Brazil
| | - Annemieke Geluk
- Department of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
| | | | | | | | | | | | - Maria C. V. Pessolani
- Laboratory of Cellular Microbiology, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, Brazil
| | - Patrick J. Brennan
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Geraldo M. B. Pereira
- Laboratory of Cellular Microbiology, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, Brazil
- Laboratory of Immunopathology, School of Medical Sciences, State University of Rio de Janeiro, Rio de Janeiro, Brazil
- * E-mail:
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Geluk A, Bobosha K, van der Ploeg-van Schip JJ, Spencer JS, Banu S, Martins MVSB, Cho SN, Franken KLMC, Kim HJ, Bekele Y, Uddin MKM, Hadi SA, Aseffa A, Pessolani MCV, Pereira GMB, Dockrell HM, Ottenhoff THM. New biomarkers with relevance to leprosy diagnosis applicable in areas hyperendemic for leprosy. THE JOURNAL OF IMMUNOLOGY 2012; 188:4782-91. [PMID: 22504648 DOI: 10.4049/jimmunol.1103452] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Leprosy is not eradicable with currently available diagnostics or interventions, as evidenced by its stable incidence. Early diagnosis of Mycobacterium leprae infection should therefore be emphasized in leprosy research. It remains challenging to develop tests based on immunological biomarkers that distinguish individuals controlling bacterial replication from those developing disease. To identify biomarkers for field-applicable diagnostics, we determined cytokines/chemokines induced by M. leprae proteins in blood of leprosy patients and endemic controls (EC) from high leprosy-prevalence areas (Bangladesh, Brazil, Ethiopia) and from South Korea, where leprosy is not endemic anymore. M. leprae-sonicate-induced IFN-γ was similar for all groups, excluding M. leprae/IFN-γ as a diagnostic readout. By contrast, ML2478 and ML0840 induced high IFN-γ concentrations in Bangladeshi EC, which were completely absent for South Korean controls. Importantly, ML2478/IFN-γ could indicate distinct degrees of M. leprae exposure, and thereby the risk of infection and transmission, in different parts of Brazilian and Ethiopian cities. Notwithstanding these discriminatory responses, M. leprae proteins did not distinguish patients from EC in one leprosy-endemic area based on IFN-γ. Analyses of additional cytokines/chemokines showed that M. leprae and ML2478 induced significantly higher concentrations of MCP-1, MIP-1β, and IL-1β in patients compared with EC, whereas IFN-inducible protein-10, like IFN-γ, differed between EC from areas with dissimilar leprosy prevalence. This study identifies M. leprae-unique Ags, particularly ML2478, as biomarker tools to measure M. leprae exposure using IFN-γ or IFN-inducible protein-10, and also shows that MCP-1, MIP-1β, and IL-1β can potentially distinguish pathogenic immune responses from those induced during asymptomatic exposure to M. leprae.
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Affiliation(s)
- Annemieke Geluk
- Department of Infectious Diseases, Leiden University Medical Center, Leiden 2333 ZA, The Netherlands.
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Peptides Derived from Mycobacterium leprae ML1601c Discriminate between Leprosy Patients and Healthy Endemic Controls. J Trop Med 2012; 2012:132049. [PMID: 22363349 PMCID: PMC3272838 DOI: 10.1155/2012/132049] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Accepted: 10/07/2011] [Indexed: 11/20/2022] Open
Abstract
The stable incidence of new leprosy cases suggests that transmission of infection continues despite worldwide implementation of MDT. Thus, specific tools are needed to diagnose early stage Mycobacterium leprae infection, the likely sources of transmission. M. leprae antigens that induce T-cell responses in M. leprae exposed and/or infected individuals thus are major targets for new diagnostic tools. Previously, we showed that ML1601c was immunogenic in patients and healthy household contacts (HHC). However, some endemic controls (EC) also recognized this protein. To improve the diagnostic potential, IFN-γ responses to ML1601c peptides were assessed using PBMC from Brazilian leprosy patients and EC. Five ML1601c peptides only induced IFN-γ in patients and HHC. Moreover, 24-hour whole-blood assay (WBA), two ML1601c peptides could assess the level of M. leprae exposure in Ethiopian EC. Beside IFN-γ, also IP-10, IL-6, IL-1β, TNF-α, and MCP-1 were increased in EC from areas with high leprosy prevalence in response to these ML1601c peptides. Thus, ML1601c peptides may be useful for differentiating M. leprae exposed or infected individuals and can also be used to indicate the magnitude of M. leprae transmission even in the context of various HLA alleles as present in these different genetic backgrounds.
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Evaluation of various cytokines elicited during antigen-specific recall as potential risk indicators for the differential development of leprosy. Eur J Clin Microbiol Infect Dis 2011; 31:1443-51. [DOI: 10.1007/s10096-011-1462-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Accepted: 10/11/2011] [Indexed: 10/15/2022]
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Checkley AM, Wyllie DH, Scriba TJ, Golubchik T, Hill AVS, Hanekom WA, McShane H. Identification of antigens specific to non-tuberculous mycobacteria: the Mce family of proteins as a target of T cell immune responses. PLoS One 2011; 6:e26434. [PMID: 22046285 PMCID: PMC3201954 DOI: 10.1371/journal.pone.0026434] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Accepted: 09/27/2011] [Indexed: 11/19/2022] Open
Abstract
The lack of an effective TB vaccine hinders current efforts in combating the TB pandemic. One theory as to why BCG is less protective in tropical countries is that exposure to non-tuberculous mycobacteria (NTM) reduces BCG efficacy. There are currently several new TB vaccines in clinical trials, and NTM exposure may also be relevant in this context. NTM exposure cannot be accurately evaluated in the absence of specific antigens; those which are known to be present in NTM and absent from M. tuberculosis and BCG. We therefore used a bioinformatic pipeline to define proteins which are present in common NTM and absent from the M. tuberculosis complex, using protein BLAST, TBLASTN and a short sequence protein BLAST to ensure the specificity of this process. We then assessed immune responses to these proteins, in healthy South Africans and in patients from the United Kingdom and United States with documented exposure to NTM. Low level responses were detected to a cluster of proteins from the mammalian cell entry family, and to a cluster of hypothetical proteins, using ex vivo ELISpot and a 6 day proliferation assay. These early findings may provide a basis for characterising exposure to NTM at a population level, which has applications in the field of TB vaccine design as well as in the development of diagnostic tests.
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Affiliation(s)
- Anna M Checkley
- The Jenner Institute, Nuffield Department of Medicine, Oxford University, ORCRB, Oxford, United Kingdom.
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Fischer EAJ, de Vlas SJ, Habbema JDF, Richardus JH. The long-term effect of current and new interventions on the new case detection of leprosy: a modeling study. PLoS Negl Trop Dis 2011; 5:e1330. [PMID: 21949895 PMCID: PMC3176744 DOI: 10.1371/journal.pntd.0001330] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Accepted: 08/10/2011] [Indexed: 11/19/2022] Open
Abstract
Background Although the number of newly detected leprosy cases has decreased globally, a quarter of a million new cases are detected annually and eradication remains far away. Current options for leprosy prevention are contact tracing and BCG vaccination of infants. Future options may include chemoprophylaxis and early diagnosis of subclinical infections. This study compared the predicted trends in leprosy case detection of future intervention strategies. Methods Seven leprosy intervention scenarios were investigated with a microsimulation model (SIMCOLEP) to predict future leprosy trends. The baseline scenario consisted of passive case detection, multidrug therapy, contact tracing, and BCG vaccination of infants. The other six scenarios were modifications of the baseline, as follows: no contact tracing; with chemoprophylaxis; with early diagnosis of subclinical infections; replacement of the BCG vaccine with a new tuberculosis vaccine ineffective against Mycobacterium leprae (“no BCG”); no BCG with chemoprophylaxis; and no BCG with early diagnosis. Findings Without contact tracing, the model predicted an initial drop in the new case detection rate due to a delay in detecting clinical cases among contacts. Eventually, this scenario would lead to new case detection rates higher than the baseline program. Both chemoprophylaxis and early diagnosis would prevent new cases due to a reduction of the infectious period of subclinical cases by detection and cure of these cases. Also, replacing BCG would increase the new case detection rate of leprosy, but this effect could be offset with either chemoprophylaxis or early diagnosis. Conclusions This study showed that the leprosy incidence would be reduced substantially by good BCG vaccine coverage and the combined strategies of contact tracing, early diagnosis, and treatment of infection and/or chemoprophylaxis among household contacts. To effectively interrupt the transmission of M. leprae, it is crucial to continue developing immuno- and chemoprophylaxis strategies and an effective test for diagnosing subclinical infections. Leprosy is a contagious disease that will remain prevalent, despite the declining number of patients worldwide over the last century. With approximately 250,000 new cases detected annually, leprosy is far from being eradicated. Leprosy can be treated with drugs after disease detection. Some cases can be prevented with a tuberculosis vaccine (BCG) that cross-reacts with the bacterium responsible for leprosy, but this vaccine might be replaced in the future. Furthermore, preventive drugs can reduce the number of new cases among people in contact with infectious patients, but this strategy has not yet become established in common practice. Also, a new test is under development for the detection of infections before the appearance of symptoms. In this study, we used a computer model to assess the effectiveness of seven possible leprosy control activities. Our results showed that the decline in incidence of leprosy would slow down or halt with the introduction of a new tuberculosis vaccine that is ineffective against leprosy. However, this effect could be offset by the implementation of effective tests for early diagnosis or the routine administration of preventative drugs to contacts of patients.
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Affiliation(s)
- Egil A. J. Fischer
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Sake J. de Vlas
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - J. Dik F Habbema
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Jan Hendrik Richardus
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
- * E-mail:
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Geluk A, van den Eeden SJF, Dijkman K, Wilson L, Kim HJ, Franken KLMC, Spencer JS, Pessolani MCV, Pereira GMB, Ottenhoff THM. ML1419c peptide immunization induces Mycobacterium leprae-specific HLA-A*0201-restricted CTL in vivo with potential to kill live mycobacteria. THE JOURNAL OF IMMUNOLOGY 2011; 187:1393-402. [PMID: 21705623 DOI: 10.4049/jimmunol.1100980] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
MHC class I-restricted CD8(+) T cells play an important role in protective immunity against mycobacteria. Previously, we showed that p113-121, derived from Mycobacterium leprae protein ML1419c, induced significant IFN-γ production by CD8(+) T cells in 90% of paucibacillary leprosy patients and in 80% of multibacillary patients' contacts, demonstrating induction of M. leprae-specific CD8(+) T cell immunity. In this work, we studied the in vivo role and functional profile of ML1419c p113-121-induced T cells in HLA-A*0201 transgenic mice. Immunization with 9mer or 30mer covering the p113-121 sequence combined with TLR9 agonist CpG induced HLA-A*0201-restricted, M. leprae-specific CD8(+) T cells as visualized by p113-121/HLA-A*0201 tetramers. Most CD8(+) T cells produced IFN-γ, but distinct IFN-γ(+)/TNF-α(+) populations were detected simultaneously with significant secretion of CXCL10/IFN-γ-induced protein 10, CXCL9/MIG, and VEGF. Strikingly, peptide immunization also induced high ML1419c-specific IgG levels, strongly suggesting that peptide-specific CD8(+) T cells provide help to B cells in vivo, as CD4(+) T cells were undetectable. An additional important characteristic of p113-121-specific CD8(+) T cells was their capacity for in vivo killing of p113-121-labeled, HLA-A*0201(+) splenocytes. The cytotoxic function of p113-121/HLA-A*0201-specific CD8(+) T cells extended into direct killing of splenocytes infected with live Mycobacterium smegmatis expressing ML1419c: both 9mer and 30mer induced CD8(+) T cells that reduced the number of ML1419c-expressing mycobacteria by 95%, whereas no reduction occurred using wild-type M. smegmatis. These data, combined with previous observations in Brazilian cohorts, show that ML1419c p113-121 induces potent CD8(+) T cells that provide protective immunity against M. leprae and B cell help for induction of specific IgG, suggesting its potential use in diagnostics and as a subunit (vaccine) for M. leprae infection.
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Affiliation(s)
- Annemieke Geluk
- Department of Infectious Diseases, Leiden University Medical Center, Leiden 2333 ZA, The Netherlands.
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Singh P, Cole ST. Mycobacterium leprae: genes, pseudogenes and genetic diversity. Future Microbiol 2011; 6:57-71. [PMID: 21162636 DOI: 10.2217/fmb.10.153] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Leprosy, which has afflicted human populations for millenia, results from infection with Mycobacterium leprae, an unculturable pathogen with an exceptionally long generation time. Considerable insight into the biology and drug resistance of the leprosy bacillus has been obtained from genomics. M. leprae has undergone reductive evolution and pseudogenes now occupy half of its genome. Comparative genomics of four different strains revealed remarkable conservation of the genome (99.995% identity) yet uncovered 215 polymorphic sites, mainly single nucleotide polymorphisms, and a handful of new pseudogenes. Mapping these polymorphisms in a large panel of strains defined 16 single nucleotide polymorphism-subtypes that showed strong geographical associations and helped retrace the evolution of M. leprae.
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Affiliation(s)
- Pushpendra Singh
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne, Station 19, CH-1015 Lausanne, Switzerland
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Spencer JS, Kim HJ, Wheat WH, Chatterjee D, Balagon MV, Cellona RV, Tan EV, Gelber R, Saunderson P, Duthie MS, Reece ST, Burman W, Belknap R, Mac Kenzie WR, Geluk A, Oskam L, Dockrell HM, Brennan PJ. Analysis of antibody responses to Mycobacterium leprae phenolic glycolipid I, lipoarabinomannan, and recombinant proteins to define disease subtype-specific antigenic profiles in leprosy. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2011; 18:260-7. [PMID: 21177913 PMCID: PMC3067349 DOI: 10.1128/cvi.00472-10] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Revised: 11/24/2010] [Accepted: 12/13/2010] [Indexed: 01/21/2023]
Abstract
A simple serodiagnostic test based on the Mycobacterium leprae-specific phenolic glycolipid I(PGL-I), for individuals with leprosy is nearly universally positive in leprosy patients with high bacillary loads but cannot be used as a stand-alone diagnostic test for the entire spectrum of the disease process. For patients with early infection with no detectable acid-fast bacilli in lesions or with low or no antibody titer to PGL-I, as in those at the tuberculoid end of the disease spectrum, this diagnostic approach has limited usefulness. To identify additional M. leprae antigens that might enhance the serological detection of these individuals, we have examined the reactivity patterns of patient sera to PGL-I, lipoarabinomannan (LAM), and six recombinant M. leprae proteins (ML1877, ML0841, ML2028, ML2038, ML0380, and ML0050) by Western blot analysis and enzyme-linked immunosorbent assay (ELISA). Overall, the responses to ML2028 (Ag85B) and ML2038 (bacterioferritin) were consistently high in both multibacillary and paucibacillary groups and weak or absent in endemic controls, while responses to other antigens showed considerable variability, from strongly positive to completely negative. This analysis has given a clearer understanding of some of the differences in the antibody responses between individuals at opposite ends of the disease spectrum, as well as illustrating the heterogeneity of antibody responses toward protein, carbohydrate, and glycolipid antigens within a clinical group. Correlating these response patterns with a particular disease state could allow for a more critical assessment of the form of disease within the leprosy spectrum and could lead to better patient management.
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Affiliation(s)
- John S Spencer
- Department of Microbiology, Immunology and Pathology, Colorado State University, Campus Delivery 1682, Fort Collins, CO 80523-1682, USA.
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Sampaio LH, Stefani MMA, Oliveira RM, Sousa ALM, Ireton GC, Reed SG, Duthie MS. Immunologically reactive M. leprae antigens with relevance to diagnosis and vaccine development. BMC Infect Dis 2011; 11:26. [PMID: 21269435 PMCID: PMC3040138 DOI: 10.1186/1471-2334-11-26] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Accepted: 01/26/2011] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND Leprosy is a chronic infectious disease caused by Mycobacterium leprae that can manifest a wide variety of immunological and clinical outcomes ranging from potent humoral responses among borderline lepromatous (BL) and lepromatous (LL) patients to strong cellular responses among tuberculoid (TT) and borderline tuberculoid (BT) patients. Until recently, relatively little has been known about the immune responses to individual proteins of M. leprae recognized during leprosy. METHODS The immune reactivity to a panel of 33 M. leprae recombinant proteins was evaluated among leprosy patients and controls from a high endemic area for leprosy (Goiania/GO, Central Brazil). Serum IgG responses were measured by ELISA (45 participants/group) and T cell responses (20 participants/group) were evaluated by IFN-gamma production in 24 hours whole blood cultures with antigen (whole blood assay-WBA). Study groups were newly diagnosed, untreated TT/BT and BL/LL leprosy patients classified by Ridley Jopling criteria and household contacts of BL/LL patients (HHC). Control groups were HIV-1 negative pulmonary tuberculosis patients (TB) and healthy individuals from the same endemic area (EC). In silico predictions indicated the level of identity of M. leprae proteins with homologues in other mycobacteria and the presence of T cell and B cell epitopes. RESULTS Despite the prediction that all proteins would be reactive, 16 of 33 (48%) of the single proteins tested were immunogenic (recognized in WBA or ELISA) and seventeen were non-immunogenic (not recognized in either assay). Among the 16 immunogenic proteins, 9 were considered leprosy specific in WBA inducing cell-mediated IFN-gamma secretion from TT/BT patients and HHC. Three of these proteins were also leprosy specific in serology being recognized by serum IgG from LL/BL patients. Seven of the immunogenic proteins were not leprosy specific. CONCLUSIONS New M. leprae antigens recognized by antibody responses of BL/LL patients and cellular responses of TT/BT leprosy patients were identified. An improved serological diagnostic test for leprosy could be developed by incorporating these IgG-reactive antigens to the current PGL-I based tests. Moreover our data indicate that the WBA is a robust, relatively simple and user friendly format for a T cell based diagnostic test. The field use of these test formats in leprosy endemic countries could contribute to early leprosy diagnosis before the development of deformities and disabilities.
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Affiliation(s)
- Lucas H Sampaio
- Tropical Pathology and Public Health Institute, Federal University of Goiás, Rua 235 esquina com 1a Avenida, Setor Universitário, sala 335, Goiânia, GO, 74605050, Brazil
| | - Mariane MA Stefani
- Tropical Pathology and Public Health Institute, Federal University of Goiás, Rua 235 esquina com 1a Avenida, Setor Universitário, sala 335, Goiânia, GO, 74605050, Brazil
| | - Regiane M Oliveira
- Tropical Pathology and Public Health Institute, Federal University of Goiás, Rua 235 esquina com 1a Avenida, Setor Universitário, sala 335, Goiânia, GO, 74605050, Brazil
| | - Ana LM Sousa
- Tropical Pathology and Public Health Institute, Federal University of Goiás, Rua 235 esquina com 1a Avenida, Setor Universitário, sala 335, Goiânia, GO, 74605050, Brazil
| | - Greg C Ireton
- Infectious Disease Research Institute, 1124 Columbia St, Suite 400, Seattle, WA 98104, USA
| | - Steven G Reed
- Infectious Disease Research Institute, 1124 Columbia St, Suite 400, Seattle, WA 98104, USA
| | - Malcolm S Duthie
- Infectious Disease Research Institute, 1124 Columbia St, Suite 400, Seattle, WA 98104, USA
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Wiker HG, Tomazella GG, de Souza GA. A quantitative view on Mycobacterium leprae antigens by proteomics. J Proteomics 2011; 74:1711-9. [PMID: 21278007 DOI: 10.1016/j.jprot.2011.01.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Revised: 12/09/2010] [Accepted: 01/10/2011] [Indexed: 11/29/2022]
Abstract
Leprosy is an ancient disease and the focus of the researchers' scrutiny for more than a century. However, many of the molecular aspects related to transmission, virulence, antigens and immune responses are far from known. Initially, the implementation of recombinant DNA library screens raised interesting antigen candidates. Finally, the availability of Mycobacterium leprae genomic information showed an intriguing genome reduction which is now largely used in comparative genomics. While predictive in silico tools are commonly used to identify possible antigens, proteomic approaches have not yet been explored fully to study M. leprae biology. Quantitative information obtained at the protein level, and its analysis as part of a complex system, would be a key feature to be used to help researchers to validate and understand many of such in silico predictions. Through a re-analysis of data from a previous publication of our group, we could easily tackle many questions regarding antigen prediction and pseudogene expression. Several well known antigens are among the quantitatively dominant proteins, while several major proteins have not been explored as antigens. We argue that combining proteomic approaches together with bioinformatic workflows is a required step in the characterization of important pathogens.
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Affiliation(s)
- Harald G Wiker
- The Gade Institute, Section for Microbiology and Immunology, University of Bergen, Norway.
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Abstract
PURPOSE OF REVIEW After tuberculosis, leprosy (Mycobacterium leprae) and Buruli ulcer (M. ulcerans infection) are the second and third most common mycobacterial infections in humankind, respectively. Recent advances in both diseases are summarized. RECENT FINDINGS Leprosy remains a public health problem in some countries, and new case detections indicate active transmission. Newly identified M. lepromatosis, closely related to M. leprae, may cause disseminated leprosy in some regions. In genome-wide screening in China, leprosy susceptibility associates with polymorphisms in seven genes, many involved with innate immunity. World Health Organization multiple drug therapy administered for 1 or 2 years effectively arrests disseminated leprosy but disability remains a public health concern. Relapse is infrequent, often associated with higher pretreatment M. leprae burdens. M. ulcerans, a re-emerging environmental organism, arose from M. marinum and acquired a virulence plasmid coding for mycolactone, a necrotizing, immunosuppressive toxin. Geographically, there are multiple strains of M. ulcerans, with variable pathogenicity and immunogenicity. Molecular epidemiology is describing M. ulcerans evolution and genotypic variants. First-line therapy for Buruli ulcer is rifampin + streptomycin, sometimes with surgery, but improved regimens are needed. SUMMARY Leprosy and Buruli ulcer are important infections with significant public health implications. Modern research is providing new insights into molecular epidemiology and pathogenesis, boding well for improved control strategies.
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Enhancing sensitivity of detection of immune responses to Mycobacterium leprae peptides in whole-blood assays. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2010; 17:993-1004. [PMID: 20427628 DOI: 10.1128/cvi.00046-10] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Although worldwide leprosy prevalence has been reduced considerably following multidrug therapy, new case detection rates remain relatively stable, suggesting that transmission of infection still continues. This calls for new efforts, among which is development of assays that can identify subclinical/early-stage Mycobacterium leprae-infected subjects, a likely source of transmission. Areas in which leprosy is endemic often lack sophisticated laboratories, necessitating development of field-friendly immunodiagnostic tests for leprosy, like short-term whole-blood assays (WBA). In classical, peripheral blood mononuclear cell (PBMC)-based gamma interferon (IFN-gamma) release assays, M. leprae peptides have been shown to discriminate in a more specific fashion than M. leprae proteins between M. leprae-exposed contacts and patients as opposed to healthy controls from the same area of endemicity. However, peptides induced significantly lower levels of IFN-gamma than did proteins, particularly when whole blood was used. Therefore, possibilities of specifically enhancing IFN-gamma production in response to M. leprae peptides in 24-h WBA were sought by addition of various cytokines and antibodies or by mannosylation of peptides. In addition, other cytokines and chemokines were analyzed as potential biomarkers in WBA. We found that only interleukin 12 (IL-12), not other costimulants, increased IFN-gamma production in WBA while maintaining M. leprae peptide specificity, as evidenced by lack of increase of IFN-gamma in control samples stimulated with IL-12 alone. The IL-12-induced increase in IFN-gamma was mainly mediated by CD4+ T cells that did not produce IL-2 or tumor necrosis factor (TNF). Mannosylation further allowed the use of 100-fold-less peptide. Although not statistically significantly, macrophage inflammatory protein 1beta (MIP-1beta) and macrophage c protein 1 (MCP-1) levels specific for M. leprae peptide tended to be increased by IL-12. IP-10 production was also found to be a useful marker of M. leprae peptide responses, but its production was enhanced by IL-12 nonspecifically. We conclude that IFN-gamma-based WBA combined with IL-12 represents a more sensitive and robust assay for measuring reactivity to M. leprae peptides.
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