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Detection of anti-Pneumocystis jirovecii antibodies in human serum using a recombinant synthetic multi-epitope kexin-based antigen. Eur J Clin Microbiol Infect Dis 2020; 39:2205-2209. [PMID: 32557324 PMCID: PMC7561569 DOI: 10.1007/s10096-020-03936-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 05/26/2020] [Indexed: 11/22/2022]
Abstract
Interest in the detection of specific anti-Pneumocystis jirovecii antibodies has emerged as less-invasive alternative diagnostic approaches. Here is presented the performance of an ELISA based on a recombinant synthetic multi-epitope kexin 1 (Kex1) antigen of P. jirovecii, previously developed. Results showed that IgM anti-Kex1 levels were found significantly increased in patients with Pneumocystis pneumonia (PcP) compared with non-PcP cases (p < 0.001), allowing a diagnostic performance of PcP with a 70.8% sensitivity and a 75.0% specificity. These results suggest that this Kex1-based ELISA is a promising tool toward the serodiagnosis of PcP when the standard methods are difficult to perform.
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Tomás AL, de Almeida MP, Cardoso F, Pinto M, Pereira E, Franco R, Matos O. Development of a Gold Nanoparticle-Based Lateral-Flow Immunoassay for Pneumocystis Pneumonia Serological Diagnosis at Point-of-Care. Front Microbiol 2019; 10:2917. [PMID: 31921081 PMCID: PMC6931265 DOI: 10.3389/fmicb.2019.02917] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 12/03/2019] [Indexed: 12/29/2022] Open
Abstract
Pneumocystis jirovecii pneumonia (PcP) is a major human immunodeficiency virus (HIV)-related illness, rising among immunocompromised non-HIV patients and in developing countries. Presently, the diagnosis requires respiratory specimens obtained through invasive and costly techniques that are difficult to perform in all patients or implement in all economic settings. Therefore, the development of a faster, cost-effective, non-invasive and field-friendly test to diagnose PcP would be a significant advance. In this study, recombinant synthetic antigens (RSA) of P. jirovecii's major surface glycoprotein (Msg) and kexin-like serine protease (Kex1) were produced and purified. These RSA were applied as antigenic tools in immunoenzymatic assays for detection of specific anti-P. jirovecii antibodies (IgG and IgM) in sera of patients with (n = 48) and without (n = 28) PcP. Results showed that only IgM anti-P. jirovecii levels were significantly increased in patients with PcP compared with patients without P. jirovecii infection (p ≤ 0.001 with both RSA). Thus, two strip lateral flow immunoassays (LFIA), based on the detection of specific IgM anti-P. jirovecii antibodies in human sera samples, were developed using the innovative association of P. jirovecii's RSA with spherical gold nanoparticles (AuNPs). For that, alkanethiol-functionalized spherical AuNPs with ca. ~40 nm in diameter were synthetized and conjugated with the two RSA (Msg or Kex1) produced. These AuNP-RSA conjugates were characterized by agarose gel electrophoresis (AGE) and optimized to improve their ability to interact specifically with serum IgM anti-P. jirovecii antibodies. Finally, two LFIA prototypes were developed and tested with pools of sera from patients with (positive sample) and without (negative sample) PcP. Both LFIA had the expected performance, namely, the presence of a test and control red colored lines with the positive sample, and only a control red colored line with the negative sample. These results provide valuable insights into the possibility of PcP serodiagnosis at point-of-care. The optimization, validation and implementation of this strip-based approach may help to reduce the high cost of medical diagnosis and subsequent treatment of PcP both in industrialized and low-income regions, helping to manage the disease all around the world.
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Affiliation(s)
- Ana Luísa Tomás
- Medical Parasitology Unit, Group of Opportunistic Protozoa/HIV and Other Protozoa, Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade NOVA de Lisboa, Lisbon, Portugal.,UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Miguel P de Almeida
- REQUIMTE/LAQV, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto, Porto, Portugal
| | - Fernando Cardoso
- Medical Parasitology Unit, Group of Opportunistic Protozoa/HIV and Other Protozoa, Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Mafalda Pinto
- UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Eulália Pereira
- REQUIMTE/LAQV, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto, Porto, Portugal
| | - Ricardo Franco
- UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Olga Matos
- Medical Parasitology Unit, Group of Opportunistic Protozoa/HIV and Other Protozoa, Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade NOVA de Lisboa, Lisbon, Portugal
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3
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Is the unique camouflage strategy of Pneumocystis associated with its particular niche within host lungs? PLoS Pathog 2019; 15:e1007480. [PMID: 30677096 PMCID: PMC6345417 DOI: 10.1371/journal.ppat.1007480] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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4
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Dunaiski CM, Janssen L, Erzinger H, Pieper M, Damaschek S, Schildgen O, Schildgen V. Inter-Specimen Imbalance of Mitochondrial Gene Copy Numbers Predicts Clustering of Pneumocystis jirovecii Isolates in Distinct Subgroups. J Fungi (Basel) 2018; 4:jof4030084. [PMID: 29996561 PMCID: PMC6162491 DOI: 10.3390/jof4030084] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 07/04/2018] [Accepted: 07/09/2018] [Indexed: 12/11/2022] Open
Abstract
The molecular detection of Pneumocystis jirovecii is an important therapy-relevant tool in microbiological diagnostics. However, the quantification of this pathogen in the past has revealed discordant results depending on the target gene. As the clinical variety of P. jirovecii infections ranges between life-threatening infections and symptom-free colonization, the question arises if qPCRs are reliable tools for quantitative diagnostics of P. jirovecii. P. jirovecii positive BALs were quantitatively tested for the copy numbers of one mitochondrial (COX-1) and two nuclear single-copy genes (KEX1 and DHPS) compared to the mitochondrial large subunit (mtLSU) by qPCR. Independent of the overall mtLSU copy number P. jirovecii clustered into distinct groups based on the ratio patterns of the respective qPCRs. This study, which compared different mitochondrial to nuclear gene ratio patterns of independent patients, shows that the mtLSU gene represents a highly sensitive qPCR tool for the detection of P. jirovecii, but does not display a reliable target for absolute quantification.
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Affiliation(s)
- Cara Mia Dunaiski
- Kliniken der Stadt Köln gGmbH, Institut für Pathologie, Klinikum der Privaten Universität Witten/Herdecke, 51109 Köln, Germany.
| | - Lena Janssen
- Kliniken der Stadt Köln gGmbH, Institut für Pathologie, Klinikum der Privaten Universität Witten/Herdecke, 51109 Köln, Germany.
| | - Hannah Erzinger
- Kliniken der Stadt Köln gGmbH, Institut für Pathologie, Klinikum der Privaten Universität Witten/Herdecke, 51109 Köln, Germany.
| | - Monika Pieper
- Kliniken der Stadt Köln gGmbH, Institut für Pathologie, Klinikum der Privaten Universität Witten/Herdecke, 51109 Köln, Germany.
| | - Sarah Damaschek
- Kliniken der Stadt Köln gGmbH, Institut für Pathologie, Klinikum der Privaten Universität Witten/Herdecke, 51109 Köln, Germany.
| | - Oliver Schildgen
- Kliniken der Stadt Köln gGmbH, Institut für Pathologie, Klinikum der Privaten Universität Witten/Herdecke, 51109 Köln, Germany.
| | - Verena Schildgen
- Kliniken der Stadt Köln gGmbH, Institut für Pathologie, Klinikum der Privaten Universität Witten/Herdecke, 51109 Köln, Germany.
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5
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Ma L, Chen Z, Huang DW, Kutty G, Ishihara M, Wang H, Abouelleil A, Bishop L, Davey E, Deng R, Deng X, Fan L, Fantoni G, Fitzgerald M, Gogineni E, Goldberg JM, Handley G, Hu X, Huber C, Jiao X, Jones K, Levin JZ, Liu Y, Macdonald P, Melnikov A, Raley C, Sassi M, Sherman BT, Song X, Sykes S, Tran B, Walsh L, Xia Y, Yang J, Young S, Zeng Q, Zheng X, Stephens R, Nusbaum C, Birren BW, Azadi P, Lempicki RA, Cuomo CA, Kovacs JA. Genome analysis of three Pneumocystis species reveals adaptation mechanisms to life exclusively in mammalian hosts. Nat Commun 2016; 7:10740. [PMID: 26899007 PMCID: PMC4764891 DOI: 10.1038/ncomms10740] [Citation(s) in RCA: 117] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 01/13/2016] [Indexed: 02/07/2023] Open
Abstract
Pneumocystis jirovecii is a major cause of life-threatening pneumonia in immunosuppressed patients including transplant recipients and those with HIV/AIDS, yet surprisingly little is known about the biology of this fungal pathogen. Here we report near complete genome assemblies for three Pneumocystis species that infect humans, rats and mice. Pneumocystis genomes are highly compact relative to other fungi, with substantial reductions of ribosomal RNA genes, transporters, transcription factors and many metabolic pathways, but contain expansions of surface proteins, especially a unique and complex surface glycoprotein superfamily, as well as proteases and RNA processing proteins. Unexpectedly, the key fungal cell wall components chitin and outer chain N-mannans are absent, based on genome content and experimental validation. Our findings suggest that Pneumocystis has developed unique mechanisms of adaptation to life exclusively in mammalian hosts, including dependence on the lungs for gas and nutrients and highly efficient strategies to escape both host innate and acquired immune defenses.
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Affiliation(s)
- Liang Ma
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Building 10, Room 2C145, 10 Center Drive, Bethesda, Maryland 20892, USA
| | - Zehua Chen
- Genome Sequencing and Analysis Program, Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
| | - Da Wei Huang
- Leidos BioMedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland 21701, USA
| | - Geetha Kutty
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Building 10, Room 2C145, 10 Center Drive, Bethesda, Maryland 20892, USA
| | - Mayumi Ishihara
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602, USA
| | - Honghui Wang
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Building 10, Room 2C145, 10 Center Drive, Bethesda, Maryland 20892, USA
| | - Amr Abouelleil
- Genome Sequencing and Analysis Program, Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
| | - Lisa Bishop
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Building 10, Room 2C145, 10 Center Drive, Bethesda, Maryland 20892, USA
| | - Emma Davey
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Building 10, Room 2C145, 10 Center Drive, Bethesda, Maryland 20892, USA
| | - Rebecca Deng
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Building 10, Room 2C145, 10 Center Drive, Bethesda, Maryland 20892, USA
| | - Xilong Deng
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Building 10, Room 2C145, 10 Center Drive, Bethesda, Maryland 20892, USA
| | - Lin Fan
- Genome Sequencing and Analysis Program, Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
| | - Giovanna Fantoni
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Building 10, Room 2C145, 10 Center Drive, Bethesda, Maryland 20892, USA
| | - Michael Fitzgerald
- Genome Sequencing and Analysis Program, Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
| | - Emile Gogineni
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Building 10, Room 2C145, 10 Center Drive, Bethesda, Maryland 20892, USA
| | - Jonathan M. Goldberg
- Genome Sequencing and Analysis Program, Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
| | - Grace Handley
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Building 10, Room 2C145, 10 Center Drive, Bethesda, Maryland 20892, USA
| | - Xiaojun Hu
- Leidos BioMedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland 21701, USA
| | - Charles Huber
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Building 10, Room 2C145, 10 Center Drive, Bethesda, Maryland 20892, USA
| | - Xiaoli Jiao
- Leidos BioMedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland 21701, USA
| | - Kristine Jones
- Leidos BioMedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland 21701, USA
| | - Joshua Z. Levin
- Genome Sequencing and Analysis Program, Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
| | - Yueqin Liu
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Building 10, Room 2C145, 10 Center Drive, Bethesda, Maryland 20892, USA
| | - Pendexter Macdonald
- Genome Sequencing and Analysis Program, Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
| | - Alexandre Melnikov
- Genome Sequencing and Analysis Program, Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
| | - Castle Raley
- Leidos BioMedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland 21701, USA
| | - Monica Sassi
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Building 10, Room 2C145, 10 Center Drive, Bethesda, Maryland 20892, USA
| | - Brad T. Sherman
- Leidos BioMedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland 21701, USA
| | - Xiaohong Song
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Building 10, Room 2C145, 10 Center Drive, Bethesda, Maryland 20892, USA
| | - Sean Sykes
- Genome Sequencing and Analysis Program, Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
| | - Bao Tran
- Leidos BioMedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland 21701, USA
| | - Laura Walsh
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Building 10, Room 2C145, 10 Center Drive, Bethesda, Maryland 20892, USA
| | - Yun Xia
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Building 10, Room 2C145, 10 Center Drive, Bethesda, Maryland 20892, USA
| | - Jun Yang
- Leidos BioMedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland 21701, USA
| | - Sarah Young
- Genome Sequencing and Analysis Program, Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
| | - Qiandong Zeng
- Genome Sequencing and Analysis Program, Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
| | - Xin Zheng
- Leidos BioMedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland 21701, USA
| | - Robert Stephens
- Leidos BioMedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland 21701, USA
| | - Chad Nusbaum
- Genome Sequencing and Analysis Program, Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
| | - Bruce W. Birren
- Genome Sequencing and Analysis Program, Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
| | - Parastoo Azadi
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602, USA
| | - Richard A. Lempicki
- Leidos BioMedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland 21701, USA
| | - Christina A. Cuomo
- Genome Sequencing and Analysis Program, Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
| | - Joseph A. Kovacs
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Building 10, Room 2C145, 10 Center Drive, Bethesda, Maryland 20892, USA
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Pneumocystis jirovecii--from a commensal to pathogen: clinical and diagnostic review. Parasitol Res 2015; 114:3577-85. [PMID: 26281787 PMCID: PMC4562001 DOI: 10.1007/s00436-015-4678-6] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 08/07/2015] [Indexed: 01/09/2023]
Abstract
Pneumocystis pneumonia is an opportunistic disease caused by invasion of unicellular fungus Pneumocystis jirovecii. Initially, it was responsible for majority of morbidity and mortality cases among HIV-infected patients, which later have been reduced due to the introduction of anti-retroviral therapy, as well as anti-Pneumocystis prophylaxis among these patients. Pneumocystis pneumonia, however, is still a significant cause of mortality among HIV-negative patients being under immunosuppression caused by different factors, such as transplant recipients as well as oncologically treated ones. The issue of pneumocystosis among these people is particularly emphasized in the article, since rapid onset and fast progression of severe symptoms result in high mortality rate among these patients, who thereby represent the group of highest risk of developing Pneumocystis pneumonia. In contrast, fungal invasion in immunocompetent people usually leads to asymptomatic colonization, which frequent incidence among healthy infants has even suggested the possibility of its association with sudden unexpected infant death syndrome. In the face of emerging strains with different epidemiological profiles resulting from genetic diversity, including drug-resistant genotypes, the colonization phenomenon desires particular attention, discussed in this article. We also summarize specific and sensitive methods, required for detection of Pneumocystis invasion and for distinguish colonization from the disease.
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Skalski JH, Kottom TJ, Limper AH. Pathobiology of Pneumocystis pneumonia: life cycle, cell wall and cell signal transduction. FEMS Yeast Res 2015; 15:fov046. [PMID: 26071598 DOI: 10.1093/femsyr/fov046] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/08/2015] [Indexed: 12/28/2022] Open
Abstract
Pneumocystis is a genus of ascomycetous fungi that are highly morbid pathogens in immunosuppressed humans and other mammals. Pneumocystis cannot easily be propagated in culture, which has greatly hindered understanding of its pathobiology. The Pneumocystis life cycle is intimately associated with its mammalian host lung environment, and life cycle progression is dependent on complex interactions with host alveolar epithelial cells and the extracellular matrix. The Pneumocystis cell wall is a varied and dynamic structure containing a dominant major surface glycoprotein, β-glucans and chitins that are important for evasion of host defenses and stimulation of the host immune system. Understanding of Pneumocystis cell signaling pathways is incomplete, but much has been deduced by comparison of the Pneumocystis genome with homologous genes and proteins in related fungi. In this mini-review, the pathobiology of Pneumocystis is reviewed, with particular focus on the life cycle, cell wall components and cell signal transduction.
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Affiliation(s)
- Joseph H Skalski
- Thoracic Diseases Research Unit, Division of Pulmonary and Critical Care Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
| | - Theodore J Kottom
- Thoracic Diseases Research Unit, Division of Pulmonary and Critical Care Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
| | - Andrew H Limper
- Thoracic Diseases Research Unit, Division of Pulmonary and Critical Care Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
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Abstract
Since its initial misidentification as a trypanosome some 100 years ago, Pneumocystis has remained recalcitrant to study. Although we have learned much, we still do not have definitive answers to such basic questions as, where is the reservoir of infection, how does Pneumocystis reproduce, what is the mechanism of infection, and are there true species of Pneumocystis? The goal of this review is to provide the reader the most up to date information available about the biology of Pneumocystis and the disease it produces.
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Affiliation(s)
- Francis Gigliotti
- Department of Pediatrics, University of Rochester Medical School, Rochester, New York 14642
| | - Andrew H Limper
- Pulmonary and Critical Care Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Terry Wright
- Department of Pediatrics, University of Rochester Medical School, Rochester, New York 14642
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Abstract
Although the incidence of Pneumocystis pneumonia (PCP) has decreased since the introduction of combination antiretroviral therapy, it remains an important cause of disease in both HIV-infected and non-HIV-infected immunosuppressed populations. The epidemiology of PCP has shifted over the course of the HIV epidemic both from changes in HIV and PCP treatment and prevention and from changes in critical care medicine. Although less common in non-HIV-infected immunosuppressed patients, PCP is now more frequently seen due to the increasing numbers of organ transplants and development of novel immunotherapies. New diagnostic and treatment modalities are under investigation. The immune response is critical in preventing this disease but also results in lung damage, and future work may offer potential areas for vaccine development or immunomodulatory therapy. Colonization with Pneumocystis is an area of increasing clinical and research interest and may be important in development of lung diseases such as chronic obstructive pulmonary disease. In this review, we discuss current clinical and research topics in the study of Pneumocystis and highlight areas for future research.
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Serologic responses to pneumocystis proteins in HIV patients with and without Pneumocystis jirovecii pneumonia. J Acquir Immune Defic Syndr 2011; 57:190-6. [PMID: 21372726 DOI: 10.1097/qai.0b013e3182167516] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
BACKGROUND Immune responses to Pneumocystis jirovecii are not well understood in HIV infection, but antibody responses to proteins may be useful as a marker of Pneumocystis risk or presence of Pneumocystis pneumonia (PcP). DESIGN Retrospective analysis of a prospective cohort. METHODS Enzyme-linked immunosorbent assays of antibodies to recombinant Pneumocystis proteins of major surface glycoprotein fragments (MsgC1, C3, C8, and C9) and of antibody titers to recombinant kexin protein (KEX1) were performed on 3 sequential serum samples up to 18 months before and 3 samples after first AIDS-defining illness from Multicenter AIDS Cohort Study participants and compared between those who had PcP or a non-PcP AIDS-defining illness. RESULTS Fifty-four participants had PcP and 47 had a non-PcP AIDS-defining illness. IgG levels to MsgC fragments were similar between groups before first AIDS-defining illness, but the PcP group had higher levels of IgG to MsgC9 (median units/mL 50.2 vs. 22.2, P = 0.047) post-illness. Participants with PcP were more likely to have an increase in MsgC3 [odds ratio (OR): 3.9, P = 0.02], MsgC8 (OR: 5.5, P = 0.001), and MsgC9 (OR: 4.0, P = 0.007). The PcP group was more likely to have low KEX1 IgG before development of PcP (OR: 3.6, P = 0.048) independent of CD4 cell count and to have an increase in high IgG titers to KEX1 after PcP. CONCLUSIONS HIV-infected individuals develop immune responses to both Msg and kexin proteins after PcP. Low KEX1 IgG titers may be a novel marker of future PcP risk before CD4 cell count has declined below 200 cells per microliter.
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Djawe K, Daly KR, Vargas SL, Santolaya ME, Ponce CA, Bustamante R, Koch J, Levin L, Walzer PD. Seroepidemiological study of Pneumocystis jirovecii infection in healthy infants in Chile using recombinant fragments of the P. jirovecii major surface glycoprotein. Int J Infect Dis 2011; 14:e1060-6. [PMID: 20926326 DOI: 10.1016/j.ijid.2010.07.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2010] [Revised: 06/25/2010] [Accepted: 07/03/2010] [Indexed: 11/16/2022] Open
Abstract
OBJECTIVES To characterize the seroepidemiological features of Pneumocystis jirovecii infection in healthy Chilean children using overlapping fragments (A, B, C) of the P. jirovecii major surface glycoprotein (Msg). METHODS Serum antibodies to MsgA, MsgB, and MsgC were measured every 2 months by enzyme-linked immunosorbent assay (ELISA) in 45 Chilean infants from about age 2 months to 2 years. RESULTS Peak antibody levels (usually reached at age 6 months) and the force (or rate) of infection were somewhat greater for MsgC than for MsgA. Significant seasonal variation in antibody levels was only found with MsgA. Respiratory infections occurred in most children, but nasopharyngeal aspirates were of limited value in detecting the organism. In contrast, serological responses commonly occurred, and higher levels only to MsgC were significantly related to the number of infections. CONCLUSIONS Serological responses to recombinant Msg fragments provide new insights into the epidemiological and clinical features of P. jirovecii infection of early childhood. MsgA, the amino terminus fragment, is more sensitive in detecting seasonal influences on antibody levels, whereas MsgC is better able to detect changes in antibody levels in response to clinical infection.
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Affiliation(s)
- Kpandja Djawe
- Department of Environmental Health, University of Cincinnati, Cincinnati, Ohio, USA
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12
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Djawe K, Huang L, Daly KR, Levin L, Koch J, Schwartzman A, Fong S, Roth B, Subramanian A, Grieco K, Jarlsberg L, Walzer PD. Serum antibody levels to the Pneumocystis jirovecii major surface glycoprotein in the diagnosis of P. jirovecii pneumonia in HIV+ patients. PLoS One 2010; 5:e14259. [PMID: 21151564 PMCID: PMC3000336 DOI: 10.1371/journal.pone.0014259] [Citation(s) in RCA: 21] [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: 04/26/2010] [Accepted: 11/10/2010] [Indexed: 12/27/2022] Open
Abstract
Background Pneumocystis jirovecii remains an important cause of fatal pneumonia (Pneumocystis pneumonia or PcP) in HIV+ patients and other immunocompromised hosts. Despite many previous attempts, a clinically useful serologic test for P. jirovecii infection has never been developed. Methods/Principal Findings We analyzed serum antibody responses to the P. jirovecii major surface glycoprotein recombinant fragment C1 (MsgC1) in 110 HIV+ patients with active PcP (cases) and 63 HIV+ patients with pneumonia due to other causes (controls) by an enzyme-linked immunosorbent assay (ELISA). The cases had significantly higher IgG and IgM antibody levels to MsgC1 than the controls at hospital admission (week 0) and intervals up to at least 1 month thereafter. The sensitivity, specificity and positive predictive value (PPV) of IgG antibody levels increased from 57.2%, 61.7% and 71.5% at week 0 to 63.4%, 100%, and 100%, respectively, at weeks 3–4. The sensitivity, specificity and PPV of IgM antibody levels rose from 59.7%, 61.3%, and 79.3% at week 0 to 74.6%, 73.7%, and 89.8%, respectively, at weeks 3–4. Multivariate analysis revealed that a diagnosis of PcP was the only independent predictor of high IgG and IgM antibody levels to MsgC1. A high LDH level, a nonspecific marker of lung damage, was an independent predictor of low IgG antibody levels to MsgC1. Conclusions/Significance The results suggest that the ELISA shows promise as an aid to the diagnosis of PCP in situations where diagnostic procedures cannot be performed. Further studies in other patient populations are needed to better define the usefulness of this serologic test.
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Affiliation(s)
- Kpandja Djawe
- Veterans Affairs Medical Center, Cincinnati, Ohio, United States of America
- Division of Epidemiology and Biostatistics, Department of Environmental Health, University College of Medicine, Cincinnati, Ohio, United States of America
| | - Laurence Huang
- Division of Pulmonary and Critical Care Medicine and HIV/AIDS Division, San Francisco General Hospital, University of California San Francisco, San Francisco, California, United States of America
| | - Kieran R. Daly
- Veterans Affairs Medical Center, Cincinnati, Ohio, United States of America
- Division of Infectious Diseases, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Linda Levin
- Division of Epidemiology and Biostatistics, Department of Environmental Health, University College of Medicine, Cincinnati, Ohio, United States of America
| | - Judy Koch
- Veterans Affairs Medical Center, Cincinnati, Ohio, United States of America
- Division of Infectious Diseases, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Alexandra Schwartzman
- Division of Pulmonary and Critical Care Medicine and HIV/AIDS Division, San Francisco General Hospital, University of California San Francisco, San Francisco, California, United States of America
| | - Serena Fong
- Division of Pulmonary and Critical Care Medicine and HIV/AIDS Division, San Francisco General Hospital, University of California San Francisco, San Francisco, California, United States of America
| | - Brenna Roth
- Division of Pulmonary and Critical Care Medicine and HIV/AIDS Division, San Francisco General Hospital, University of California San Francisco, San Francisco, California, United States of America
| | - Anuradha Subramanian
- Division of Pulmonary and Critical Care Medicine and HIV/AIDS Division, San Francisco General Hospital, University of California San Francisco, San Francisco, California, United States of America
| | - Katherine Grieco
- Division of Pulmonary and Critical Care Medicine and HIV/AIDS Division, San Francisco General Hospital, University of California San Francisco, San Francisco, California, United States of America
| | - Leah Jarlsberg
- Division of Pulmonary and Critical Care Medicine and HIV/AIDS Division, San Francisco General Hospital, University of California San Francisco, San Francisco, California, United States of America
| | - Peter D. Walzer
- Veterans Affairs Medical Center, Cincinnati, Ohio, United States of America
- Division of Epidemiology and Biostatistics, Department of Environmental Health, University College of Medicine, Cincinnati, Ohio, United States of America
- Division of Infectious Diseases, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
- * E-mail:
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13
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Cushion MT, Stringer JR. Stealth and Opportunism: Alternative Lifestyles of Species in the Fungal GenusPneumocystis. Annu Rev Microbiol 2010; 64:431-52. [DOI: 10.1146/annurev.micro.112408.134335] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Melanie T. Cushion
- University of Cincinnati College of Medicine, Department of Internal Medicine, Division of Infectious Diseases, Cincinnati, Ohio 45267-0560
- Veterans Affairs Medical Center, Cincinnati, Ohio 45220;
| | - James R. Stringer
- Department of Molecular Genetics, Biochemistry, and Microbiology, Cincinnati, Ohio 45267-0560; ,
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14
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Matos O, Esteves F. Pneumocystis jirovecii multilocus gene sequencing: findings and implications. Future Microbiol 2010; 5:1257-67. [DOI: 10.2217/fmb.10.75] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Pneumocystis jirovecii pneumonia (PcP) remains a major cause of respiratory illness among immunocompromised patients, especially patients infected with HIV, but it has also been isolated from immunocompetent persons. This article discusses the application of multilocus genotyping analysis to the study of the genetic diversity of P. jirovecii and its epidemiological and clinical parameters, and the important concepts achieved to date with these approaches. The multilocus typing studies performed until now have shown that there is an important genetic diversity of stable and ubiquitous P. jirovecii genotypes; infection with P. jirovecii is not necessarily clonal, recombination between some P. jirovecii multilocus genotypes has been suggested. P. jirovecii-specific multilocus genotypes can be associated with severity of PcP. Patients infected with P. jirovecii, regardless of the form of infection they present with, are part of a common human reservoir for future infections. The CYB, DHFR, DHPS, mtLSU rRNA, SOD and the ITS loci are suitable genetic targets to be used in further epidemiological studies focused on the identification and characterization of P. jirovecii haplotypes correlated with drug resistance and PcP outcome.
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Affiliation(s)
| | - Francisco Esteves
- Unidade de Protozoários Oportunistas/VIH e Outras Protozooses, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisboa, Portugal
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15
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Duan Y, Zhu D, Chen J, Qin Y, Wang J. Gene Cloning, Expression, and Immunological Characterization of Kexin in Rat Pneumocystis carinii. Lab Med 2010. [DOI: 10.1309/lmkpilyfx6yenmm4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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16
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Walzer PD, Djawe K, Levin L, Daly KR, Koch J, Kingsley L, Witt M, Golub ET, Bream JH, Taiwo B, Morris A. Long-term serologic responses to the Pneumocystis jirovecii major surface glycoprotein in HIV-positive individuals with and without P. jirovecii infection. J Infect Dis 2009; 199:1335-44. [PMID: 19301979 DOI: 10.1086/597803] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND The immune responses to Pneumocystis jirovecii major surface glycoprotein (Msg) in individuals with human immunodeficiency virus (HIV) infection are poorly understood. METHODS We examined the sequential serologic responses to recombinant Msg carboxyl terminus fragments (MsgC1, MsgC3, MsgC8, and MsgC9) by enzyme-linked immunosorbent assay in a cohort of individuals with HIV infection for the 5.5 years before death and autopsy. Analyses included mean antibody levels by status at death (Pneumocystis pneumonia, P. jirovecii colonization, or neither), factors associated with high antibody levels, and antibody responses before and after active Pneumocystis pneumonia. RESULTS Patients who died from Pneumocystis pneumonia had higher levels of antibody to MsgC8 than did patients who died from other causes. Previous episode of Pneumocystis pneumonia, geographic location, and age were independent predictors of high levels of anitbodies to most or all Msgs. Failure to take Pneumocystis pneumonia prophylaxis was associated with high levels of antibody to MsgC1. Patients who developed and recovered from active Pneumocystis pneumonia during the study exhibited an increase in serum antibody levels that persisted for months after the infection, whereas patients who developed another acquired immunodeficiency syndrome-defining illness did not. CONCLUSIONS Serum antibodies to Msgs are important markers of P. jirovecii infection in patients with HIV infection and are influenced by host and environmental factors in complex ways.
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Affiliation(s)
- Peter D Walzer
- Veterans Affairs Medical Center and Division of Infectious Diseases, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
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17
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Characterization of a novel ADAM protease expressed by Pneumocystis carinii. Infect Immun 2009; 77:3328-36. [PMID: 19451239 DOI: 10.1128/iai.01383-08] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pneumocystis species are opportunistic fungal pathogens that cause severe pneumonia in immunocompromised hosts. Recent evidence has suggested that unidentified proteases are involved in Pneumocystis life cycle regulation. Proteolytically active ADAM (named for "a disintegrin and metalloprotease") family molecules have been identified in some fungal organisms, such as Aspergillus fumigatus and Schizosaccharomyces pombe, and some have been shown to participate in life cycle regulation. Accordingly, we sought to characterize ADAM-like molecules in the fungal opportunistic pathogen, Pneumocystis carinii (PcADAM). After an in silico search of the P. carinii genomic sequencing project identified a 329-bp partial sequence with homology to known ADAM proteins, the full-length PcADAM sequence was obtained by PCR extension cloning, yielding a final coding sequence of 1,650 bp. Sequence analysis detected the presence of a typical ADAM catalytic active site (HEXXHXXGXXHD). Expression of PcADAM over the Pneumocystis life cycle was analyzed by Northern blot. Southern and contour-clamped homogenous electronic field blot analysis demonstrated its presence in the P. carinii genome. Expression of PcADAM was observed to be increased in Pneumocystis cysts compared to trophic forms. The full-length gene was subsequently cloned and heterologously expressed in Saccharomyces cerevisiae. Purified PcADAMp protein was proteolytically active in casein zymography, requiring divalent zinc. Furthermore, native PcADAMp extracted directly from freshly isolated Pneumocystis organisms also exhibited protease activity. This is the first report of protease activity attributable to a specific, characterized protein in the clinically important opportunistic fungal pathogen Pneumocystis.
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18
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Kling HM, Shipley TW, Patil S, Morris A, Norris KA. Pneumocystis colonization in immunocompetent and simian immunodeficiency virus-infected cynomolgus macaques. J Infect Dis 2009; 199:89-96. [PMID: 19014344 DOI: 10.1086/595297] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Pneumocystis (Pc) colonization is common among human immunodeficiency virus (HIV)-infected subjects, although the clinical consequences of Pc carriage are not fully understood. We examined the frequency of asymptomatic carriage in healthy and simian immunodeficiency virus (SIV)-infected cynomolgus macaques by use of polymerase chain reaction (PCR) and assessment of changes in the serologic response to a recombinant fragment of the Pc protein kexin (KEX1). Anti-KEX1 antibodies were detected in 95% of healthy monkeys. To create a model of natural transmission of Pc, SIV-infected monkeys were cohoused with macaques coinfected with SIV and Pc. Pc colonization occurred when the CD4(+) T cell count decreased to <500 cells/microL, despite anti-Pc prophylaxis with trimethoprim-sulfamethoxazole. Increases in anti-KEX1 antibody titers preceded detection of Pc DNA in bronchoalveolar lavage (BAL) fluid samples by use of PCR. These results demonstrate the usefulness of recombinant KEX1 in serologic studies of Pc colonization and will improve the understanding of Pc transmission and clinical consequences of Pc colonization in HIV-infected patients.
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Affiliation(s)
- Heather M Kling
- Department of Immunology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA
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19
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Esteves F, Tavares A, Costa MC, Gaspar J, Antunes F, Matos O. Genetic characterization of the UCS and Kex1 loci of Pneumocystis jirovecii. Eur J Clin Microbiol Infect Dis 2008; 28:175-8. [DOI: 10.1007/s10096-008-0596-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2008] [Accepted: 06/26/2008] [Indexed: 11/28/2022]
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20
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Abstract
Chronic obstructive pulmonary disease (COPD) results in significant morbidity and mortality. Smoking has long been recognized as the primary risk factor for development of COPD, but factors determining the severity or pattern of disease in smokers are largely unknown. Recent interest has focused on the potential role of infectious agents and the associated host response in accelerating progression of airway obstruction or in perpetuating its progression following discontinuation of tobacco exposure. Pneumocystis jirovecii is a fungal pathogen that causes pneumonia in immunocompromised individuals. Recent evidence has linked this organism with COPD. Using sensitive molecular techniques, low levels of Pneumocystis have been detected in the respiratory tract of certain individuals and termed colonization. Several findings support the theory that colonization with Pneumocystis is involved in the "vicious circle" hypothesis of COPD in which colonization with organisms perpetuates an inflammatory and lung remodeling response. Pneumocystis colonization is more prevalent in smokers and in those with severe COPD. The presence of Pneumocystis in the lungs, even at low levels, produces inflammatory changes similar to those seen in COPD, with increases in numbers of neutrophils and CD8(+) lymphocytes. HIV-infected subjects who have had PCP develop permanent airway obstruction, and HIV-infected patients have a high prevalence of both emphysema and Pneumocystis colonization. In addition, a non-human primate model of colonization shows development of airway obstruction and radiographic emphysema. Additional studies are needed to confirm the role of Pneumocystis in the pathogenesis of COPD, given that this agent might be a treatable co-factor in disease progression.
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Affiliation(s)
- Alison Morris
- Division of Pulmonary, Allergy, and Critical Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA.
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21
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Abstract
Pneumocystis is a genus containing many species of non-culturable fungi, each of which infects a different mammalian host. Pneumonia caused by Pneumocystis is a problem in immunodeficient humans, but not in normal humans. Nevertheless, it appears that Pneumocystis organisms cannot survive and proliferate outside of their mammalian hosts, suggesting that Pneumocystis parasitizes immunocompetent mammals. Residence in immunocompetent hosts may rely on camouflage perpetrated by antigenic variation. In P. carinii, which is found in rats, there exist three families of genes that appear to be designed to create antigenic variation. One gene family, which encodes the major surface glycoprotein (MSG), contains nearly 100 members. Expression of the MSG family is controlled by restricting transcription to the one gene that is linked to a unique expression site. Changes in the sequence of the MSG gene linked to the expression site occur and appear to be caused by recombination with MSG genes not at the expression site. Preliminary evidence suggests that gene conversion is the predominant recombination mechanism.
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Affiliation(s)
- James R Stringer
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati, Cincinnati, Ohio 45267-0524, USA.
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22
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Thomas CF, Limper AH. Current insights into the biology and pathogenesis of Pneumocystis pneumonia. Nat Rev Microbiol 2007; 5:298-308. [PMID: 17363968 DOI: 10.1038/nrmicro1621] [Citation(s) in RCA: 175] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The fungal infection Pneumocystis pneumonia is the most prevalent opportunistic infection in patients with AIDS. Although the analysis of this opportunistic fungal pathogen has been hindered by the inability to isolate it in pure culture, the use of molecular techniques and genomic analysis have brought insights into its complex cell biology. Analysis of the intricate relationship between Pneumocystis and the host lung during infection has revealed that the attachment of Pneumocystis to the alveolar epithelium promotes the transition of the organism from the trophic to the cyst form. It also revealed that Pneumocystis infection elicits the production of inflammatory mediators, culminating in lung injury and impaired gas exchange. Here we discuss these and other recent findings relating to the biology and pathogenesis of this intractable fungus.
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Affiliation(s)
- Charles F Thomas
- Thoracic Diseases Research Unit, Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Rochester, Minnesota 55905, USA.
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23
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Daly KR, Huang L, Morris A, Koch J, Crothers K, Levin L, Eiser S, Satwah S, Zucchi P, Walzer PD. Antibody response to Pneumocystis jirovecii major surface glycoprotein. Emerg Infect Dis 2006; 12. [PMID: 16965702 PMCID: PMC3291227 DOI: 10.3201/eid1208.060230] [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: 11/08/2022] Open
Abstract
We conducted a prospective pilot study of the serologic responses to overlapping recombinant fragments of the Pneumocystis jirovecii major surface glycoprotein (Msg) in HIV-infected patients with pneumonia due to P. jirovecii and other causes. Similar baseline geometric mean antibody levels to the fragments measured by an ELISA were found in both groups. Serum antibodies to MsgC in P. jirovecii patients rose to a peak level 3-4 weeks (p<0.001) after recovery from pneumocystosis; baseline CD4+ count > or =50 cells/microL and first episode of pneumocystosis were the principal host factors associated with this rise (both p<0.001). Thus, MsgC shows promise as a serologic reagent and should be tested further in clinical and epidemiologic studies.
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Affiliation(s)
- Kieran R. Daly
- Veterans Affairs Medical Center, Cincinnati, Ohio, USA;,University of Cincinnati, Cincinnati, Ohio, USA
| | - Laurence Huang
- University of California, San Francisco, California, USA
| | - Alison Morris
- University of Southern California, Los Angeles, California, USA
| | - Judy Koch
- Veterans Affairs Medical Center, Cincinnati, Ohio, USA;,University of Cincinnati, Cincinnati, Ohio, USA
| | - Kristina Crothers
- University of California, San Francisco, California, USA;,Yale University School of Medicine, New Haven, Connecticut, USA
| | - Linda Levin
- University of Cincinnati, Cincinnati, Ohio, USA
| | - Shary Eiser
- University of California, San Francisco, California, USA
| | | | - Patrizia Zucchi
- University of California, San Francisco, California, USA;,University of Pavia, Pavia, Italy
| | - Peter D. Walzer
- Veterans Affairs Medical Center, Cincinnati, Ohio, USA;,University of Cincinnati, Cincinnati, Ohio, USA
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24
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Gigliotti F. Pneumocystis carinii: Has the Name Really Been Changed? Clin Infect Dis 2005; 41:1752-5. [PMID: 16288399 DOI: 10.1086/498150] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2005] [Accepted: 07/29/2005] [Indexed: 11/03/2022] Open
Abstract
The proposed renaming of Pneumocystis carinii has caused much confusion and controversy among authors, peer reviewers, editors, and interested readers. Proponents of the new nomenclature emphasize the fact that the new names are judged to be "valid" by the International Code of Botanical Nomenclature. What is generally not appreciated is the fact that the International Code of Botanical Nomenclature does not make any determination as to the scientific correctness of proposed names; rather, it mandates the process of naming an organism. Thus, acknowledgement by the International Code of Botanical Nomenclature that new names for P. carinii have been validly published does not mandate their use. Rather, the scientific community interested in P. carinii needs to be aware of the issues involved in changing the name and then decide for themselves as to the correctness of the newly proposed names. Use of the newly proposed names for P. carinii should not be mandated by journal reviewers or editors.
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Affiliation(s)
- Francis Gigliotti
- Department of Pediatrics, Division of Pediatric Infectious Diseases, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA.
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25
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Ambrose HE, Keely SP, Aliouat EM, Dei-Cas E, Wakefield AE, Miller RF, Stringer JR. Expression and complexity of the PRT1 multigene family of Pneumocystis carinii. MICROBIOLOGY-SGM 2004; 150:293-300. [PMID: 14766907 DOI: 10.1099/mic.0.26539-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Pneumocystis carinii has a multigene family, PRT1, that encodes proteins with homology to KEX2-like proteases. PRT1 genes cluster with MSG genes near the telomeres and, like MSG, PRT1 proteins seem to be surface-expressed. The clustering of PRT1 and MSG genes suggested that expression of the two multigene families might be coordinated. Studying gene expression in P. carinii has been hampered by the lack of a culture system, and by lack of clonality in P. carinii populations in naturally infected rats, the host of this fungus. Heterogeneity can be reduced, however, by low-dose intratracheal inoculation, which can produce P. carinii populations dominated by organisms derived from a single progenitor. To study PRT1 expression, nude rats were inoculated with approximately 10 P. carinii each. The clonality of the P. carinii populations from inoculated rats was assessed by analysis of the UCS locus, a site in the genome that is known to be very heterogeneous in naturally infected rats, but nearly homogeneous in rats infected by low-dose intratracheal inoculation. Each of the populations had the same MSG gene at the UCS locus in at least 80 % of the organisms. To investigate PRT1 gene expression, RNA was amplified using primers that amplify numerous PRT1 genes. Seventy-four cloned cDNAs were sequenced, including at least 12 clones from each population of P. carinii. Many differently expressed PRT1 sequences were identified in each population, and a total of 45 different sequences were detected. However, the same PRT1 sequence was present in 15 of 74 plasmids and was found in 3 of the 5 P. carinii populations, suggesting that some PRT1 genes may be either more commonly expressed or expressed at a higher level. These data show that many members of the PRT1 gene family can be expressed in populations of P. carinii derived from few progenitors and suggest that the regulation of this family is different from that governing expression of the MSG gene family.
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Affiliation(s)
- H E Ambrose
- Molecular Infectious Diseases Group, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DU, UK
| | - S P Keely
- Department of Molecular Genetics, Biochemistry & Microbiology, University of Cincinnati, Cincinnati, OH 45267-0524, USA
| | - E M Aliouat
- Department of Parasitology, Faculty of Pharmacy, 59006, Lille, and EA3609, Institut Pasteur de Lille, 59019, Lille, France
| | - E Dei-Cas
- EA3609, Institut Pasteur de Lille, 59019, Lille, and Lille-2 University Hospital, Lille, France
| | - A E Wakefield
- Molecular Infectious Diseases Group, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DU, UK
| | - R F Miller
- Department of Sexually Transmitted Diseases, Royal Free and University College Medical School, University College London, London WC1 6AU, UK
| | - J R Stringer
- Department of Molecular Genetics, Biochemistry & Microbiology, University of Cincinnati, Cincinnati, OH 45267-0524, USA
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26
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Vohra PK, Puri V, Kottom TJ, Limper AH, Thomas CF. Pneumocystis carinii STE11, an HMG-box protein, is phosphorylated by the mitogen activated protein kinase PCM. Gene 2003; 312:173-9. [PMID: 12909353 DOI: 10.1016/s0378-1119(03)00614-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A pheromone-induced mitogen activated protein kinase (MAPK) pathway controls mating in fungi by regulating gene transcription. In the opportunistic fungus Pneumocystis carinii, we have identified a protein containing a high-mobility group (HMG) motif which is homologous to the transcriptional activators STE11 of Schizosaccharomyces pombe and STE12 of Saccharomyces cerevisiae. In fungi, this transcriptional activator functions in sexual development, filamentous growth, and pathogenicity. The fungal pheromone-activated MAPK phosphorylates the transcriptional activator to allow binding to pheromone-response elements in the promoter regions of certain genes. We have previously identified a P. carinii MAPK, PCM, which has significant homology to fungal MAPKs involved in mating. As an initial step in understanding the downstream molecules which interact with the PCM kinase, we have cloned a STE11 homologue in P. carinii. PCSTE11 has an open-reading frame of 1.5 kb which encodes a protein of 501 amino acids with a molecular weight of 56 kDa. Greatest homology was to S. pombe STE11 (52%). We have expressed a His-tag fusion of PCSTE11 and purified the protein with nickel affinity resin. PCM phosphorylates the purified protein indicating that PCSTE11 is associated with the MAPK cascade in P. carinii.
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Affiliation(s)
- Pawan K Vohra
- Thoracic Diseases Research Unit, 826 Stabile Building, Division of Pulmonary, Critical Care and Internal Medicine, Department of Medicine, Mayo Clinic and Foundation, Rochester, MN 55905, USA
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27
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Kutty G, Huang SN, Kovacs JA. Characterization of thioredoxin reductase genes (trr1) from Pneumocystis carinii and Pneumocystis jiroveci. Gene 2003; 310:175-83. [PMID: 12801645 DOI: 10.1016/s0378-1119(03)00549-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We have characterized the thioredoxin reductase (trr1) genes from Pneumocystis carinii and Pneumocystis jiroveci, and have demonstrated that multiple copies of an approximately 500 base pair fragment of the trr1 gene are present in P. carinii, but not in P. jiroveci. Thioredoxin reductases encoded by the full-length genes have predicted molecular weights of approximately 35,000 and show high homology to yeast Trr1. An NADPH-binding domain with a putative redox active site CAVC as well as an flavin-adenine dinucleotide-binding domain are highly conserved in both proteins, which were 85% identical. The multicopy trr1 gene fragments in P. carinii are not transcribed or expressed. Duplication of the gene fragment likely occurred in conjunction with duplication of the kexin homologue, protease-1, which is located immediately upstream of the trr1 gene. Thioredoxin reductase, an enzyme implicated in the growth, survival and pathogenicity of certain microbes, could be a potential target for therapeutic intervention in Pneumocystis infection.
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MESH Headings
- Amino Acid Sequence
- Ascomycota/enzymology
- Ascomycota/genetics
- Base Sequence
- Blotting, Northern
- Blotting, Southern
- DNA, Complementary/chemistry
- DNA, Complementary/genetics
- DNA, Fungal/chemistry
- DNA, Fungal/genetics
- Fungal Proteins/genetics
- Gene Expression Regulation, Enzymologic
- Gene Expression Regulation, Fungal
- Molecular Sequence Data
- Pneumocystis/enzymology
- Pneumocystis/genetics
- Saccharomyces cerevisiae/enzymology
- Saccharomyces cerevisiae/genetics
- Schizosaccharomyces/enzymology
- Schizosaccharomyces/genetics
- Sequence Alignment
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- Sequence Homology, Nucleic Acid
- Thioredoxin-Disulfide Reductase/genetics
- Thioredoxin-Disulfide Reductase/metabolism
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Affiliation(s)
- Geetha Kutty
- Critical Care Medicine Department, Warren G. Magnuson Clinical Center, National Institutes of Health, Building 10, Room 7D43, MSC 1662, Bethesda, MD 20892-1662, USA
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