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Uddin MB, Sajib EH, Hoque SF, Hassan MM, Ahmed SSU. Macrophages in respiratory system. RECENT ADVANCEMENTS IN MICROBIAL DIVERSITY 2022:299-333. [DOI: 10.1016/b978-0-12-822368-0.00014-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
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Yanagisawa K, Wichukchinda N, Tsuchiya N, Yasunami M, Rojanawiwat A, Tanaka H, Saji H, Ogawa Y, Handa H, Pathipvanich P, Ariyoshi K, Sawanpanyalert P. Deficiency of mannose-binding lectin is a risk of Pneumocystis jirovecii pneumonia in a natural history cohort of people living with HIV/AIDS in Northern Thailand. PLoS One 2020; 15:e0242438. [PMID: 33362211 PMCID: PMC7757797 DOI: 10.1371/journal.pone.0242438] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 11/02/2020] [Indexed: 01/23/2023] Open
Abstract
Background Mannose-binding lectin (MBL) plays a pivotal role in innate immunity; however, its impact on susceptibility to opportunistic infections (OIs) has not yet been examined in a natural history cohort of people living with HIV/AIDS. Methods We used archived samples to analyze the association between MBL expression types and risk of major OIs including Pneumocystis jirovecii pneumonia (PCP), cryptococcosis, talaromycosis, toxoplasmosis, and tuberculosis in a prospective cohort in Northern Thailand conducted from 1 July 2000 to 15 October 2002 before the national antiretroviral treatment programme was launched. Results Of 632 patients, PCP was diagnosed in 96 (15.2%) patients, including 45 patients with new episodes during the follow-up period (1006.5 person-years). The total history of PCP was significantly associated with low MBL expression type: high/intermediate (81/587, 13.8%), low (10/33, 30.3%) and deficient (5/12, 41.7%) (p = 0.001), whereas the history of other OIs showed no relation with any MBL expression type. Kaplan–Meier analysis (n = 569; log-rank p = 0.011) and Cox’s proportional hazards model revealed that deficient genotype dramatically increased the risk of PCP, which is independent upon sex, age, CD4 count, HIV-1 viral load and hepatitis B and C status (adjusted hazard ratio 7.93, 95% confidence interval 2.19–28.67, p = 0.002). Conclusions Deficiency of MBL expression is a strong risk factor determining the incidence of PCP but not other major OIs.
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Affiliation(s)
- Kunio Yanagisawa
- Department of Hematology, Gunma University Hospital, Maebashi, Japan
- Infection Control and Prevention Center, Gunma University Hospital, Maebashi, Japan
| | | | - Naho Tsuchiya
- Department of Preventive Medicine and Epidemiology, Tohoku Medical Megabank Organization, Tohoku University, Sendai, Japan
| | - Michio Yasunami
- Department of Laboratory Medicine, Saga-Ken Medical Centre Koseikan, Saga, Japan
| | | | | | | | - Yoshiyuki Ogawa
- Department of Hematology, Gunma University Hospital, Maebashi, Japan
| | - Hiroshi Handa
- Department of Hematology, Gunma University Hospital, Maebashi, Japan
| | | | - Koya Ariyoshi
- Department of Clinical Medicine, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
- * E-mail:
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Affiliation(s)
- Sushma K Cribbs
- Division of Pulmonary, Allergy, Critical Care & Sleep Medicine, Emory University School of Medicine, Atlanta, Georgia
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Cribbs SK, Crothers K, Morris A. Pathogenesis of HIV-Related Lung Disease: Immunity, Infection, and Inflammation. Physiol Rev 2019; 100:603-632. [PMID: 31600121 DOI: 10.1152/physrev.00039.2018] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Despite anti-retroviral therapy (ART), human immunodeficiency virus-1 (HIV)-related pulmonary disease continues to be a major cause of morbidity and mortality for people living with HIV (PLWH). The spectrum of lung diseases has changed from acute opportunistic infections resulting in death to chronic lung diseases for those with access to ART. Chronic immune activation and suppression can result in impairment of innate immunity and progressive loss of T cell and B cell functionality with aberrant cytokine and chemokine responses systemically as well as in the lung. HIV can be detected in the lungs of PLWH and has profound effects on cellular immune functions. In addition, HIV-related lung injury and disease can occur secondary to a number of mechanisms including altered pulmonary and systemic inflammatory pathways, viral persistence in the lung, oxidative stress with additive effects of smoke exposure, microbial translocation, and alterations in the lung and gut microbiome. Although ART has had profound effects on systemic viral suppression in HIV, the impact of ART on lung immunology still needs to be fully elucidated. Understanding of the mechanisms by which HIV-related lung diseases continue to occur is critical to the development of new preventive and therapeutic strategies to improve lung health in PLWH.
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Affiliation(s)
- Sushma K Cribbs
- Pulmonary Medicine, Department of Veterans Affairs, Atlanta, Georgia; Department of Medicine, Division of Pulmonary, Allergy, Critical Care and Sleep, Emory University, Atlanta, Georgia; Department of Medicine, Veterans Affairs Puget Sound Health Care System and Division of Pulmonary, Critical Care and Sleep Medicine, University of Washington, Seattle, Washington; and Department of Medicine, Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Kristina Crothers
- Pulmonary Medicine, Department of Veterans Affairs, Atlanta, Georgia; Department of Medicine, Division of Pulmonary, Allergy, Critical Care and Sleep, Emory University, Atlanta, Georgia; Department of Medicine, Veterans Affairs Puget Sound Health Care System and Division of Pulmonary, Critical Care and Sleep Medicine, University of Washington, Seattle, Washington; and Department of Medicine, Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Alison Morris
- Pulmonary Medicine, Department of Veterans Affairs, Atlanta, Georgia; Department of Medicine, Division of Pulmonary, Allergy, Critical Care and Sleep, Emory University, Atlanta, Georgia; Department of Medicine, Veterans Affairs Puget Sound Health Care System and Division of Pulmonary, Critical Care and Sleep Medicine, University of Washington, Seattle, Washington; and Department of Medicine, Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
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Gupta-Wright A, Tembo D, Jambo KC, Chimbayo E, Mvaya L, Caldwell S, Russell DG, Mwandumba HC. Functional Analysis of Phagocyte Activity in Whole Blood from HIV/Tuberculosis-Infected Individuals Using a Novel Flow Cytometry-Based Assay. Front Immunol 2017; 8:1222. [PMID: 29033941 PMCID: PMC5624998 DOI: 10.3389/fimmu.2017.01222] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 09/15/2017] [Indexed: 12/02/2022] Open
Abstract
The accurate assessment of immune competence through ex vivo analysis is paramount to our understanding of those immune mechanisms that lead to protection or susceptibility against a broad range of human pathogens. We have developed a flow cytometry-based, whole blood phagocyte functional assay that utilizes the inflammatory inducer zymosan, coupled to OxyBURST-SE, a fluorescent reporter of phagosomal oxidase activity. The assay measures both phagocytic uptake and the superoxide burst in the phagocyte populations in whole blood. We utilized this assay to demonstrate impaired superoxide burst activity in the phagocytes of hospitalized HIV-positive patients with laboratory-confirmed tuberculosis. These data validate the use of the assay to assess the immune competence of patients in a clinical setting. The method is highly reproducible with minimal intraindividual variation and opens opportunities for the rapid assessment of cellular immune competence in peripheral blood in a disease setting.
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Affiliation(s)
- Ankur Gupta-Wright
- College of Medicine, Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi.,Clinical Research Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Dumizulu Tembo
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY, United States
| | - Kondwani C Jambo
- College of Medicine, Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi.,Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Elizabeth Chimbayo
- College of Medicine, Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Leonard Mvaya
- College of Medicine, Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Shannon Caldwell
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY, United States
| | - David G Russell
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY, United States
| | - Henry C Mwandumba
- College of Medicine, Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi.,Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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Staitieh BS, Egea EE, Guidot DM. Pulmonary Innate Immune Dysfunction in Human Immunodeficiency Virus. Am J Respir Cell Mol Biol 2017; 56:563-567. [PMID: 27911588 PMCID: PMC5449488 DOI: 10.1165/rcmb.2016-0213tr] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The advent of antiretroviral therapy has transformed infection by the type 1 human immunodeficiency virus (HIV) from a rapidly fatal disease to a chronic illness with excellent long-term survival rates. Although HIV primarily targets the adaptive arm of host immunity, it simultaneously impacts the innate immune system, and has profound implications for lung health, even when viral suppression is achieved with antiretroviral therapy. The lung has evolved a unique array of innate immune defenses, and the pathophysiological interactions between HIV and the pulmonary innate immune system deserve particular attention. In this review, we discuss work that elucidates how the components of innate immunity both respond to and are perturbed by infection with HIV.
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Affiliation(s)
- Bashar S Staitieh
- 1 Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Emory University School of Medicine, Atlanta, Georgia; and
| | - Eduardo E Egea
- 1 Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Emory University School of Medicine, Atlanta, Georgia; and
| | - David M Guidot
- 1 Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Emory University School of Medicine, Atlanta, Georgia; and.,2 the Atlanta Veterans Administration Medical Center, Decatur, Georgia
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Abstract
Domestic smoke exposure and early HIV infection are critical but unseen risk factors for pneumonia. This paper reviews how recent research in Malawi and elsewhere contributes to an understanding of the possible immunological mechanisms underlying these risks.
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Affiliation(s)
- D G Fullerton
- Department of Respiratory Medicine Hope Hospital, Stott Lane, Salford, M6 8HD, U.K
| | - S B Gordon
- Malawi-Liverpool-Wellcome Clinical Research Programme, University of Malawi, Blantyre, Malawi
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Abstract
Pneumocystis carinii pneumonia (PCP) remains a serious infection in the immunocompromised host (in the absence of HIV infection) and presents significant management and diagnostic challenges to ICU physicians. Non-HIV PCP is generally abrupt in onset, and follows a fulminate course with high rates of hospitalization, ICT admission, respiratory failure, and requirement for intubation. Mortality is generally high, especially if mechanical ventilation is required. Non-invasive ventilatory support may be considered, although the rapid progression to respiratory failure often necessitates intubation at the time of presentation. Bronchoscopy is often required to establish the diagnosis, and empirical antimicrobial treatment specifically targeted to P. carinii should be initiated while awaiting confirmation. Adjunctive corticosteroids may accelerate recovery, although their use has not yet been established in non-HIV PCP. For the ICU physicians to diagnose PCP, the non-specific presentation of an acute febrile illness and respiratory distress with diffuse pulmonary infiltrates requires a high clinical index of suspician, familiarity with clinical conditions associated with increased risk for PCP, and a low threshold for bronchoscopy to establish the diagnosis.
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Affiliation(s)
- Geoffrey S. Gilmartin
- Division of Pulmonary and Critical Care, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA
| | - Henry Koziel
- Division of Pulmonary and Critical Care, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA.,
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Charles TP, Shellito JE. Human Immunodeficiency Virus Infection and Host Defense in the Lungs. Semin Respir Crit Care Med 2016; 37:147-56. [PMID: 26974294 DOI: 10.1055/s-0036-1572553] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Immunosuppression associated with human immunodeficiency virus (HIV) infection impacts all components of host defense against pulmonary infection. Cells within the lung have altered immune function and are important reservoirs for HIV infection. The host immune response to infected lung cells further compromises responses to a secondary pathogenic insult. In the upper respiratory tract, mucociliary function is impaired and there are decreased levels of salivary immunoglobulin A. Host defenses in the lower respiratory tract are controlled by alveolar macrophages, lymphocytes, and polymorphonuclear leukocytes. As HIV infection progresses, lung CD4 T cells are reduced in number causing a lack of activation signals from CD4 T cells and impaired defense by macrophages. CD8 T cells, on the other hand, are increased in number and cause lymphocytic alveolitis. Specific antibody responses by B-lymphocytes are decreased and opsonization of microorganisms is impaired. These observed defects in host defense of the respiratory tract explain the susceptibility of HIV-infected persons for oropharyngeal candidiasis, bacterial pneumonia, Pneumocystis pneumonia, and other opportunistic infections.
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Affiliation(s)
- Tysheena P Charles
- Section of Pulmonary/Critical Care & Allergy/Immunology, Department of Medicine, Louisiana State University Health Sciences Center, New Orleans, Louisiana
| | - Judd E Shellito
- Section of Pulmonary/Critical Care & Allergy/Immunology, Department of Medicine, Louisiana State University Health Sciences Center, New Orleans, Louisiana
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Genomic Analysis of Salmonella enterica Serovar Typhimurium Characterizes Strain Diversity for Recent U.S. Salmonellosis Cases and Identifies Mutations Linked to Loss of Fitness under Nitrosative and Oxidative Stress. mBio 2016; 7:e00154. [PMID: 26956590 PMCID: PMC4810482 DOI: 10.1128/mbio.00154-16] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Salmonella enterica serovar Typhimurium is one of the most common S. enterica serovars associated with U.S. foodborne outbreaks. S. Typhimurium bacteria isolated from humans exhibit wide-ranging virulence phenotypes in inbred mice, leading to speculation that some strains are more virulent in nature. However, it is unclear whether increased virulence in humans is related to organism characteristics or initial treatment failure due to antibiotic resistance. Strain diversity and genetic factors contributing to differential human pathogenicity remain poorly understood. We reconstructed phylogeny, resolved genetic population structure, determined gene content and nucleotide variants, and conducted targeted phenotyping assays for S. Typhimurium strains collected between 1946 and 2012 from humans and animals in the United States and abroad. Strains from recent U.S. salmonellosis cases were associated with five S. Typhimurium lineages distributed within three phylogenetic clades, which are not restricted by geography, year of acquisition, or host. Notably, two U.S. strains and four Mexican strains are more closely related to strains associated with human immunodeficiency virus (HIV)-infected individuals in sub-Saharan Africa than to other North American strains. Phenotyping studies linked variants specific to these strains in hmpA and katE to loss of fitness under nitrosative and oxidative stress, respectively. These results suggest that U.S. salmonellosis is caused by diverse S. Typhimurium strains circulating worldwide. One lineage has mutations in genes affecting fitness related to innate immune system strategies for fighting pathogens and may be adapting to immunocompromised humans by a reduction in virulence capability, possibly due to a lack of selection for its maintenance as a result of the worldwide HIV epidemic. Nontyphoidal Salmonella bacteria cause an estimated 1.2 million illnesses annually in the United States, 80 million globally, due to ingestion of contaminated food or water. Salmonella Typhimurium is one of the most common serovars associated with foodborne illness, causing self-limiting gastroenteritis and, in approximately 5% of infected patients, systemic infection. Although some S. Typhimurium strains are speculated to be more virulent than others, it is unknown how strain diversity and genetic factors contribute to differential human pathogenicity. Ours is the first study to examine the diversity of S. Typhimurium associated with recent cases of U.S. salmonellosis and to provide some initial correlation between observed genotypes and phenotypes. Definition of specific S. Typhimurium lineages based on such phenotype/genotype correlations may identify strains with greater capability of associating with specific food sources, allowing outbreaks to be more quickly identified. Additionally, defining simple correlates of pathogenesis may have predictive value for patient outcome.
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11
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Yanagisawa K, Ogawa Y, Uchiumi H, Gohda F, Mawatari M, Ishizaki T, Mitsui T, Yokohama A, Handa H, Tsukamoto N, Nojima Y. Gene polymorphisms of mannose-binding lectin confer susceptibility to Pneumocystis pneumonia in HIV-infected patients. J Infect Chemother 2015; 21:769-75. [PMID: 26271591 DOI: 10.1016/j.jiac.2015.07.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 06/12/2015] [Accepted: 07/13/2015] [Indexed: 11/16/2022]
Abstract
BACKGROUND Mannose-binding lectin (MBL) plays an important role in innate immunity. The aim of this study was to determine whether genetic variants of MBL confer susceptibility to Pneumocystis pneumonia (PCP) in patients with advanced human immunodeficiency virus (HIV) infections. OBJECTIVE HIV patients (n = 53) having CD4 counts <200/μL who were admitted to our hospital were analyzed. Of these 53 patients, 30 had PCP at admission, and 23 did not. Genotypes at six single nucleotide polymorphisms (SNP) in MBL2 gene and serum MBL levels were determined for each patient, and compared between patients with or without PCP. We also examined whether MBL enhances phagocytosis of macrophages against rat-type Pneumocystis organism in vitro. RESULTS Genotypes associated with low production of MBL were significantly more common in the PCP group than in the non-PCP group (P = 0.049, odds ratio 2.17, 95% CI 1.02-4.63). Serum MBL levels were significantly higher in the non-PCP group (P = 0.039). Findings from in vitro experiments indicated that MBL act as a direct opsonin enhancing macrophage-mediated phagocytosis of Pneumocystis organisms. CONCLUSION Genetic variation of MBL production influences susceptibility to PCP in patients with advanced HIV infection, and can be regarded as a risk factor for PCP.
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Affiliation(s)
- Kunio Yanagisawa
- Gunma University Graduate School of Medicine, Department and Medicine and Clinical Science, Japan
| | - Yoshiyuki Ogawa
- Gunma University Graduate School of Medicine, Department and Medicine and Clinical Science, Japan.
| | - Hideki Uchiumi
- Gunma University Graduate School of Medicine, Department and Medicine and Clinical Science, Japan
| | - Fumito Gohda
- Gunma University Graduate School of Medicine, Department and Medicine and Clinical Science, Japan
| | - Momoko Mawatari
- Gunma University Graduate School of Medicine, Department and Medicine and Clinical Science, Japan
| | - Takuma Ishizaki
- Gunma University Graduate School of Medicine, Department and Medicine and Clinical Science, Japan
| | - Takeki Mitsui
- Gunma University Graduate School of Medicine, Department and Medicine and Clinical Science, Japan
| | - Akihiko Yokohama
- Gunma University Hospital, Division of Blood Transfusion Service, Japan
| | - Hiroshi Handa
- Gunma University Graduate School of Medicine, Department and Medicine and Clinical Science, Japan
| | | | - Yoshihisa Nojima
- Gunma University Graduate School of Medicine, Department and Medicine and Clinical Science, Japan
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12
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Swamydas M, Break TJ, Lionakis MS. Mononuclear phagocyte-mediated antifungal immunity: the role of chemotactic receptors and ligands. Cell Mol Life Sci 2015; 72:2157-75. [PMID: 25715741 DOI: 10.1007/s00018-015-1858-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 01/26/2015] [Accepted: 02/11/2015] [Indexed: 12/12/2022]
Abstract
Over the past two decades, fungal infections have emerged as significant causes of morbidity and mortality in patients with hematological malignancies, hematopoietic stem cell or solid organ transplantation and acquired immunodeficiency syndrome. Besides neutrophils and CD4(+) T lymphocytes, which have long been known to play an indispensable role in promoting protective antifungal immunity, mononuclear phagocytes are now being increasingly recognized as critical mediators of host defense against fungi. Thus, a recent surge of research studies has focused on understanding the mechanisms by which resident and recruited monocytes, macrophages and dendritic cells accumulate and become activated at the sites of fungal infection. Herein, we critically review how a variety of G-protein coupled chemoattractant receptors and their ligands mediate mononuclear phagocyte recruitment and effector function during infection by the most common human fungal pathogens.
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Affiliation(s)
- Muthulekha Swamydas
- Fungal Pathogenesis Unit, Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institute of Health, 9000 Rockville Pike, Building 10, Room 11C102, Bethesda, MD, 20892, USA
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Hernandez JC, Giraldo DM, Paul S, Urcuqui-Inchima S. Involvement of neutrophil hyporesponse and the role of Toll-like receptors in human immunodeficiency virus 1 protection. PLoS One 2015; 10:e0119844. [PMID: 25785697 PMCID: PMC4364960 DOI: 10.1371/journal.pone.0119844] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Accepted: 01/16/2015] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVES Neutrophils contribute to pathogen clearance through pattern recognition receptors (PRRs) activation. However, the role of PRRs in neutrophils in both HIV-1-infected [HIV-1(+)] and HIV-1-exposed seronegative individuals (HESN) is unknown. Here, a study was carried out to evaluate the level of PRR mRNAs and cytokines produced after activation of neutrophils from HIV-1(+), HESN and healthy donors. METHODS The neutrophils were stimulated with specific agonists for TLR2, TLR4 and TLR9 in the presence of HIV-1 particles. Pro-inflammatory cytokine production, expression of neutrophil activation markers and reactive oxygen species (ROS) production were analyzed in neutrophils from HESN, HIV-1(+) and healthy donors (controls). RESULTS We found that neutrophils from HESN presented reduced expression of PRR mRNAs (TLR4, TLR9, NOD1, NOD2, NLRC4 and RIG-I) and reduced expression of cytokine mRNAs (IL-1β, IL-6, IL-18, TNF-α and TGF-β). Moreover, neutrophils from HESN were less sensitive to stimulation through TLR4. Furthermore, neutrophils from HESN challenged with HIV-1 and stimulated with TLR2 and TLR4 agonists, produced significantly lower levels of reactive oxygen species, versus HIV-1(+). CONCLUSIONS A differential pattern of PRR expression and release of innate immune factors in neutrophils from HESN is evident. Our results suggest that lower neutrophil activation can be involved in protection against HIV-1 infection.
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Affiliation(s)
- Juan C. Hernandez
- INFETTARE, Facultad de Medicina, Universidad Cooperativa de Colombia, Medellin, Colombia
| | - Diana M. Giraldo
- Grupo Inmunovirología, Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia
| | - Stephane Paul
- GIMAP EA3064, Faculté de Medicine de Saint Etienne, Université de Lyon, Lyon, France
| | - Silvio Urcuqui-Inchima
- Grupo Inmunovirología, Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia
- * E-mail:
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Khalife S, Aliouat EM, Gantois N, Jakobczyk H, Demay F, Chabé M, Pottier M, Dabboussi F, Hamze M, Dei-Cas E, Standaert-Vitse A, Aliouat-Denis CM. Complementation of a manganese-dependent superoxide dismutase-deficient yeast strain with Pneumocystis carinii sod2 gene. Fungal Biol 2014; 118:885-95. [PMID: 25442292 DOI: 10.1016/j.funbio.2014.07.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 07/22/2014] [Accepted: 07/30/2014] [Indexed: 11/25/2022]
Abstract
Manganese-dependent superoxide dismutase (MnSOD) is one of the key enzymes involved in the cellular defense against oxidative stress. Previously, the Pneumocystis carinii sod2 gene (Pcsod2) was isolated and characterized. Based on protein sequence comparison, Pcsod2 was suggested to encode a putative MnSOD protein likely to be targeted into the mitochondrion. In this work, the Pcsod2 was cloned and expressed as a recombinant protein in EG110 Saccharomyces cerevisiae strain lacking the MnSOD-coding gene (Scsod2) in order to investigate the function and subcellular localization of P. carinii MnSOD (PcMnSOD). The Pcsod2 gene was amplified by PCR and cloned into the pYES2.1/V5-His-TOPO(®) expression vector. The recombinant construct was then transformed into EG110 strain. Once its expression had been induced, PcMnSOD was able to complement the growth defect of EG110 yeast cells that had been exposed to the redox-cycling compound menadione. N-term sequencing of the PcMnSOD protein allowed identifying the cleavage site of a mitochondrial targeting peptide. Immune-colocalization of PcMnSOD and yeast CoxIV further confirmed the mitochondrial localization of the PcMnSOD. Heterologous expression of PcMnSOD in yeast indicates that Pcsod2 encodes an active MnSOD, targeted to the yeast mitochondrion that allows the yeast cells to grow in the presence of reactive oxygen species (ROS).
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Affiliation(s)
- Sara Khalife
- Centre d'Infection et d'Immunité de Lille, INSERM U1019, CNRS UMR 8204, Univ Lille Nord de France, Institut Pasteur de Lille, Univ Lille2, Lille F-59019, France; Laboratoire de Microbiologie Santé et Environnement, Centre AZM pour la Recherche en Biotechnologie et ses Applications, Université Libanaise, Tripoli, Liban
| | - El Moukhtar Aliouat
- Centre d'Infection et d'Immunité de Lille, INSERM U1019, CNRS UMR 8204, Univ Lille Nord de France, Institut Pasteur de Lille, Univ Lille2, Lille F-59019, France; Laboratoire de Parasitologie, Faculté de Pharmacie, Univ Lille 2, Lille F-59006, France
| | - Nausicaa Gantois
- Centre d'Infection et d'Immunité de Lille, INSERM U1019, CNRS UMR 8204, Univ Lille Nord de France, Institut Pasteur de Lille, Univ Lille2, Lille F-59019, France
| | - Hélène Jakobczyk
- Centre d'Infection et d'Immunité de Lille, INSERM U1019, CNRS UMR 8204, Univ Lille Nord de France, Institut Pasteur de Lille, Univ Lille2, Lille F-59019, France
| | - François Demay
- Centre d'Infection et d'Immunité de Lille, INSERM U1019, CNRS UMR 8204, Univ Lille Nord de France, Institut Pasteur de Lille, Univ Lille2, Lille F-59019, France
| | - Magali Chabé
- Centre d'Infection et d'Immunité de Lille, INSERM U1019, CNRS UMR 8204, Univ Lille Nord de France, Institut Pasteur de Lille, Univ Lille2, Lille F-59019, France; Laboratoire de Parasitologie, Faculté de Pharmacie, Univ Lille 2, Lille F-59006, France
| | - Muriel Pottier
- Centre d'Infection et d'Immunité de Lille, INSERM U1019, CNRS UMR 8204, Univ Lille Nord de France, Institut Pasteur de Lille, Univ Lille2, Lille F-59019, France; Laboratoire de Parasitologie, Faculté de Pharmacie, Univ Lille 2, Lille F-59006, France
| | - Fouad Dabboussi
- Laboratoire de Microbiologie Santé et Environnement, Centre AZM pour la Recherche en Biotechnologie et ses Applications, Université Libanaise, Tripoli, Liban
| | - Monzer Hamze
- Laboratoire de Microbiologie Santé et Environnement, Centre AZM pour la Recherche en Biotechnologie et ses Applications, Université Libanaise, Tripoli, Liban
| | - Eduardo Dei-Cas
- Centre d'Infection et d'Immunité de Lille, INSERM U1019, CNRS UMR 8204, Univ Lille Nord de France, Institut Pasteur de Lille, Univ Lille2, Lille F-59019, France; Laboratoire de Parasitologie-Mycologie, CHRU de Lille & Faculté de Médecine de Lille, Univ Lille Nord de France, Univ Lille 2, Lille F-59045, France
| | - Annie Standaert-Vitse
- Centre d'Infection et d'Immunité de Lille, INSERM U1019, CNRS UMR 8204, Univ Lille Nord de France, Institut Pasteur de Lille, Univ Lille2, Lille F-59019, France; Laboratoire de Parasitologie, Faculté de Pharmacie, Univ Lille 2, Lille F-59006, France.
| | - Cécile-Marie Aliouat-Denis
- Centre d'Infection et d'Immunité de Lille, INSERM U1019, CNRS UMR 8204, Univ Lille Nord de France, Institut Pasteur de Lille, Univ Lille2, Lille F-59019, France; Laboratoire de Parasitologie, Faculté de Pharmacie, Univ Lille 2, Lille F-59006, France
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15
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Classical versus alternative macrophage activation: the Ying and the Yang in host defense against pulmonary fungal infections. Mucosal Immunol 2014; 7:1023-35. [PMID: 25073676 DOI: 10.1038/mi.2014.65] [Citation(s) in RCA: 112] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 06/21/2014] [Indexed: 02/04/2023]
Abstract
Macrophages are innate immune cells that possess unique abilities to polarize toward different phenotypes. Classically activated macrophages are known to have major roles in host defense against various microbial pathogens, including fungi, while alternatively activated macrophages are instrumental in immune-regulation and wound healing. Macrophages in the lungs are often the first responders to pulmonary fungal pathogens, and the macrophage polarization state has the potential to be a deciding factor in disease progression or resolution. This review discusses the distinct macrophage polarization states and their roles during pulmonary fungal infection. We focus primarily on Cryptococcus neoformans and Pneumocystis model systems as disease resolution of these two opportunistic fungal pathogens is linked to classically or alternatively activated macrophages, respectively. Further research considering macrophage polarization states that result in anti-fungal activity has the potential to provide a novel approach for the treatment of fungal infections.
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16
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Almodovar S. The complexity of HIV persistence and pathogenesis in the lung under antiretroviral therapy: challenges beyond AIDS. Viral Immunol 2014; 27:186-99. [PMID: 24797368 DOI: 10.1089/vim.2013.0130] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Antiretroviral therapy (ART) represents a significant milestone in the battle against AIDS. However, we continue learning about HIV and confronting challenges 30 years after its discovery. HIV has cleverly tricked both the host immune system and ART. First, the many HIV subtypes and recombinant forms have different susceptibilities to antiretroviral drugs, which may represent an issue in countries where ART is just being introduced. Second, even under the suppressive pressures of ART, HIV still increases inflammatory mediators, deregulates apoptosis and proliferation, and induces oxidative stress in the host. Third, the preference of HIV for CXCR4 as a co-receptor may also have noxious outcomes, including potential malignancies. Furthermore, HIV still replicates cryptically in anatomical reservoirs, including the lung. HIV impairs bronchoalveolar T-lymphocyte and macrophage immune responses, rendering the lung susceptible to comorbidities. In addition, HIV-infected individuals are significantly more susceptible to long-term HIV-associated complications. This review focuses on chronic obstructive pulmonary disease (COPD), pulmonary arterial hypertension, and lung cancer. Almost two decades after the advent of highly active ART, we now know that HIV-infected individuals on ART live as long as the uninfected population. Fortunately, its availability is rapidly increasing in low- and middle-income countries. Nevertheless, ART is not risk-free: the developed world is facing issues with antiretroviral drug toxicity, resistance, and drug-drug interactions, while developing countries are confronting issues with immune reconstitution inflammatory syndrome. Several aspects of the complexity of HIV persistence and challenges with ART are discussed, as well as suggestions for new avenues of research.
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Affiliation(s)
- Sharilyn Almodovar
- Pulmonary Sciences and Critical Care Medicine, University of Colorado Denver Anschutz Medical Campus , Aurora, Colorado
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17
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Olivetta E, Tirelli V, Chiozzini C, Scazzocchio B, Romano I, Arenaccio C, Sanchez M. HIV-1 Nef impairs key functional activities in human macrophages through CD36 downregulation. PLoS One 2014; 9:e93699. [PMID: 24705461 PMCID: PMC3976297 DOI: 10.1371/journal.pone.0093699] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 03/08/2014] [Indexed: 01/01/2023] Open
Abstract
Monocytes and macrophages utilize the class A and B scavenger receptors to recognize and perform phagocytosis of invading microbes before a pathogen-specific immune response is generated. HIV-1 Nef protein affects the innate immune system impairing oxidative burst response and phagocytic capacity of macrophages. Our data show that exogenous recombinant myristoylated Nef protein induces a marked CD36 downregulation in monocytes from Peripheral Blood Mononuclear Cells, in Monocyte-Derived Macrophages (MDMs) differentiated by cytokines and in MDMs contained in a mixed culture obtained expanding PBMCs under Human Erythroid Massive Amplification condition. Under the latter culture condition we identify three main populations after 6 days of expansion: lymphocytes (37.8±14.7%), erythroblasts (46.7±6.1%) and MDMs (15.7±7.5%). The Nef addition to the cell culture significantly downregulates CD36 expression in MDMs, but not in erythroid cells. Furthermore, CD36 inhibition is highly specific since it does not modify the expression levels of other MDM markers such as CD14, CD11c, CD86, CD68, CD206, Toll-like Receptor 2 and Toll-like Receptor 4. Similar results were obtained in MDMs infected with VSV-G pseudotyped HIV-1-expressing Nef. The reduced CD36 membrane expression is associated with decrease of correspondent CD36 mRNA transcript. Furthermore, Nef-induced CD36 downregulation is linked to both impaired scavenger activity with reduced capability to take up oxidized lipoproteins and to significant decreased phagocytosis of fluorescent beads and GFP-expressing Salmonella tiphymurium. In addition we observed that Nef induces TNF-α release in MDMs. Although these data suggest a possible involvement of TNF-α in mediating Nef activity, our results exclude a possible relationship between Nef-induced TNF-α release and Nef-mediated CD36 downregulation. The present work shows that HIV-1 Nef protein may have a role in the strategies elaborated by HIV-1 to alter pathogen disease outcomes, by modulating CD36 expression in macrophages, favoring the onset of opportunistic infections in HIV-1 infected people.
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Affiliation(s)
| | - Valentina Tirelli
- Department of Cell Biology and Neurosciences, Istituto Superiore di Sanità, Rome, Italy
| | | | - Beatrice Scazzocchio
- Department of Veterinary, Public Health and Food Safety, Istituto Superiore di Sanità, Rome, Italy
| | - Ignazio Romano
- Department of Cell Biology and Neurosciences, Istituto Superiore di Sanità, Rome, Italy
| | - Claudia Arenaccio
- National AIDS Centre, Istituto Superiore di Sanità, Rome, Italy; Department of Science, University Roma TRE, Rome, Italy
| | - Massimo Sanchez
- Department of Cell Biology and Neurosciences, Istituto Superiore di Sanità, Rome, Italy
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18
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Nelson B, Zhou X, White M, Hartshorn K, Takahashi K, Kinane TB, Anandaiah A, Koziel H. Recombinant human mannose-binding lectin dampens human alveolar macrophage inflammatory responses to influenza A virus in vitro. J Leukoc Biol 2014; 95:715-722. [PMID: 24399838 DOI: 10.1189/jlb.0313161] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 11/21/2013] [Accepted: 11/29/2013] [Indexed: 11/24/2022] Open
Abstract
IAV pneumonia remains a serious global health problem, and preventative and therapeutic strategies remain limited. AM are critical effector cells in the control of influenza, impairing IAV replication, promoting IAV clearance, and promoting efferocytosis and resolution of lung inflammation. MBL, an innate immune pattern recognition molecule, present in the lungs, binds IAV, and plasma MBL deficiency is associated with increased susceptibility to IAV, although the mechanism remains incompletely understood, and the influence of MBL on the IAV-AM interaction has not been established. In the current study, focusing on human macrophages (U937 cell line and clinically relevant human AM), data demonstrated that unopsonized IAV is readily internalized, induced release of TNF and ROS, and promoted macrophage apoptosis. In contrast, IAV, opsonized with rhMBL, reduced IAV uptake and macrophage apoptosis and dramatically reduced TNF release and ROS. Macrophage host-defense responses were reduced further in the presence of MASPs. Taken together, these data support the concept that rhMBL may serve a protective innate host response and a critical biological response modifier function by limiting AM inflammation, oxidative injury, and AM apoptosis, which may allow effective IAV clearance while limiting collateral damage to vital organs, such as the lungs.
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Affiliation(s)
- Benjamin Nelson
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.,Division of Pulmonary Medicine, Department of Pediatrics, Massachusetts General Hospital for Children and Harvard Medical School, Boston, Massachusetts, USA
| | - Xiuqin Zhou
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Mitchell White
- Departments of Medicine and Pathology, Boston University School of Medicine and the Department of Medicine, Boston City Hospital, Boston, Massachusetts, USA; and
| | - Kevan Hartshorn
- Departments of Medicine and Pathology, Boston University School of Medicine and the Department of Medicine, Boston City Hospital, Boston, Massachusetts, USA; and
| | - Kazue Takahashi
- Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - T Bernard Kinane
- Division of Pulmonary Medicine, Department of Pediatrics, Massachusetts General Hospital for Children and Harvard Medical School, Boston, Massachusetts, USA.,Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Asha Anandaiah
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Henry Koziel
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA;
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19
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Costiniuk CT, Jenabian MA. The lungs as anatomical reservoirs of HIV infection. Rev Med Virol 2013; 24:35-54. [DOI: 10.1002/rmv.1772] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 09/25/2013] [Accepted: 09/26/2013] [Indexed: 12/24/2022]
Affiliation(s)
- Cecilia T. Costiniuk
- KwaZulu-Natal Research Institute for Tuberculosis and HIV (K-RITH); Durban South Africa
- Division of Infectious Diseases, Department of Medicine; University of Ottawa; Ottawa ON Canada
| | - Mohammad-Ali Jenabian
- Chronic Viral Illnesses Service; Montreal Chest Institute; Montreal QC Canada
- Research Institute; McGill University Health Centre; Montreal QC Canada
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20
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The alveolar microenvironment of patients infected with human immunodeficiency virus does not modify alveolar macrophage interactions with Streptococcus pneumoniae. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2013; 20:882-91. [PMID: 23576675 DOI: 10.1128/cvi.00582-12] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
We tested the hypothesis that HIV infection results in activation of alveolar macrophages and that this might be associated with impaired defense against pneumococcus. We compared alveolar macrophages and lymphocytes in 131 bronchoalveolar lavage samples from HIV-infected and healthy controls using inflammatory gene microarrays, flow cytometry, real-time PCR, and enzyme-linked immunosorbent assay (ELISA) to determine the pattern of macrophage activation associated with HIV infection and the effect of this activation on defense against pneumococcus. We used gamma interferon (IFN-γ) priming to mimic the cellular milieu in HIV-infected lungs. InnateDB and BioLayout 3D were used to analyze the interactions of the upregulated genes. Alveolar macrophages from HIV-infected adults showed increased gene expression and cytokine production in a classical pattern. Bronchoalveolar lavage from HIV-infected subjects showed excess CD8(+) lymphocytes with activated phenotype. Toll-like receptor 4 (TLR4) expression was increased in macrophages from HIV-infected subjects, but function was similar between the groups; lung lavage fluid did not inhibit TLR function in transfected HeLa cells. Alveolar macrophages from HIV-infected subjects showed normal binding and internalization of opsonized pneumococci, with or without IFN-γ priming. Alveolar macrophages from HIV-infected subjects showed classical activation compared to that of healthy controls, but this does not alter macrophage interactions with pneumococci.
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21
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Alli OAT, Ogbolu DO, Ademola O, Oyenike MA. Molecular detection of pneumocystis jirovecii in patients with respiratory tract infections. NORTH AMERICAN JOURNAL OF MEDICAL SCIENCES 2012; 4:479-85. [PMID: 23112970 PMCID: PMC3482780 DOI: 10.4103/1947-2714.101993] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Background: Pneumocystis jirovecii, formerly known as P. carinii, is an opportunistic fungus causing Pneumocystis carinii pneumonia especially in immunocompromised patients. Aim: The aim of this study was to detect P. jirovecii in sputum samples from patients suspected of having respiratory tract infections. Materials and Methods: In this study, 230 acid fast bacilli negative sputum samples from 230 patients presenting with respiratory tract infections submitted to three teaching hospitals’ medical microbiology laboratories in Osun and Oyo States, Nigeria for routine investigation were examined for P. jirovecii by microscopical and polymerase chain reaction methods. Results: P. jirovecii cysts were observed in 15 (6.5%) samples and polymerase chain reaction was positive for 29 (12.6%) samples out of 230 samples examined. It was observed that the detection of P. jirovecii was associated with age (P < 0.05) while there were no associations between diagnosis, sex, and prevalence of P. jirovecii (P > 0.05). Polymerase chain reaction was showed to be a better method for the detection of P. jirovecii based on the 51.7% sensitivity and 100% specificity of the microscopy. Conclusion: The study concluded that P. jirovecii is prevalent in patients with respiratory tract infections in hospitals from the southwestern part of Nigeria and should be included in diagnosis of these infections in this part of the world.
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Affiliation(s)
- Oyebode Armstrong Terry Alli
- Department of Biomedical Sciences, College of Health Sciences, Ladoke Akintola University of Technology, Osogbo, Nigeria
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22
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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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23
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Porter KM, Sutliff RL. HIV-1, reactive oxygen species, and vascular complications. Free Radic Biol Med 2012; 53:143-59. [PMID: 22564529 PMCID: PMC3377788 DOI: 10.1016/j.freeradbiomed.2012.03.019] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Revised: 03/16/2012] [Accepted: 03/18/2012] [Indexed: 02/07/2023]
Abstract
Over 1 million people in the United States and 33 million individuals worldwide suffer from HIV/AIDS. Since its discovery, HIV/AIDS has been associated with an increased susceptibility to opportunistic infection due to immune dysfunction. Highly active antiretroviral therapies restore immune function and, as a result, people infected with HIV-1 are living longer. This improved survival of HIV-1 patients has revealed a previously unrecognized risk of developing vascular complications, such as atherosclerosis and pulmonary hypertension. The mechanisms underlying these HIV-associated vascular disorders are poorly understood. However, HIV-induced elevations in reactive oxygen species (ROS), including superoxide and hydrogen peroxide, may contribute to vascular disease development and progression by altering cell function and redox-sensitive signaling pathways. In this review, we summarize the clinical and experimental evidence demonstrating HIV- and HIV antiretroviral therapy-induced alterations in reactive oxygen species and how these effects are likely to contribute to vascular dysfunction and disease.
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Affiliation(s)
- Kristi M Porter
- Pulmonary, Allergy and Critical Care Division, Emory University School of Medicine/Atlanta VA Medical Center, 1670 Clairmont Road, Mailstop 151P, Decatur, GA 30033, USA.
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24
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Duan YN, Yi LH, Chen JL, Zhu DD, Wang JX, Feng JR, Qin YW, Zhu Y. Protective effect of DNA vaccine with the gene encoding 55kDa antigen fragment against Pneumocystis carinii in mice. ASIAN PAC J TROP MED 2011; 4:353-6. [PMID: 21771675 DOI: 10.1016/s1995-7645(11)60102-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Revised: 04/27/2011] [Accepted: 05/05/2011] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE To evaluate the protective effect of DNA vaccine with the gene encoding 55kDa antigen fragment of Pneumocystis carinii (P. carinii) against P. carinii in mice. METHODS The fragment of the antigen within p55(p55-582) was cloned. Then recombinant plasmid was constructed based on the eukaryotic expression vector pcDNA3.1(+). BALB/c mice were used as experimental models to examine the immunogenicity of pcDNA3.1(+)-p55-582. ELISA and RT-PCR were used to evaluate the role of this kind of DNA vaccine. RESULTS The results of western blot indicated that the recombinant DNA[pcDNA3.1(+)-p55-582] could be expressed correctly and had antigenicity in transfected COS-7 cells. ELISA and RT-PCR showed that pcDNA3.1(+)-p55-582 elicited antibody production, stimulated lymphocyte proliferation and provided partial protection by reducing the P. carinii burden. CONCLUSIONS The data demonstrate that pcDNA3.1(+)-p55-582 might be potent vaccination that can afford the partial protection for the immunized animals.
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Affiliation(s)
- Yi-nong Duan
- Department of Parasitology and Microbiology, School of Medicine, Nantong University, Nantong, Jiangsu Province, 226001, China.
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25
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Nelson MP, Christmann BS, Werner JL, Metz AE, Trevor JL, Lowell CA, Steele C. IL-33 and M2a alveolar macrophages promote lung defense against the atypical fungal pathogen Pneumocystis murina. THE JOURNAL OF IMMUNOLOGY 2011; 186:2372-81. [PMID: 21220696 DOI: 10.4049/jimmunol.1002558] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We have recently reported that mice deficient in the myeloid Src-family tyrosine kinases Hck, Fgr, and Lyn (Src triple knockout [TKO]) had augmented innate lung clearance of Pneumocystis murina that correlated with a higher ability of alveolar macrophages (AMs) from these mice to kill P. murina. In this article, we show that despite possessing enhanced killing, AMs from naive Src TKO mice did not demonstrate enhanced inflammatory responses to P. murina. We subsequently discovered that both AMs and lungs from P. murina-infected Src TKO mice expressed significantly greater levels of the M2a markers RELM-α and Arg1, and the M2a-associated chemokines CCL17 and CCL22 than did wild-type mice. IL-4 and IL-13, the primary cytokines that promote M2a polarization, were not differentially produced in the lungs between wild-type and Src TKO mice. P. murina infection in Src TKO mice resulted in enhanced lung production of the novel IL-1 family cytokine IL-33. Immunohistochemical analysis of IL-33 in lung tissue revealed localization predominantly in the nucleus of alveolar epithelial cells. We further demonstrate that experimental polarization of naive AMs to M2a resulted in more efficient killing of P. murina compared with untreated AMs, which was further enhanced by the addition of IL-33. Administration of IL-33 to C57BL/6 mice increased lung RELM-α and CCL17 levels, and enhanced clearance of P. murina, despite having no effect on the cellular composition of the lungs. Collectively, these results indicate that M2a AMs are potent effector cells against P. murina. Furthermore, enhancing M2a polarization may be an adjunctive therapy for the treatment of Pneumocystis.
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Affiliation(s)
- Michael P Nelson
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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26
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Iriart X, Witkowski B, Courtais C, Abbes S, Tkaczuk J, Courtade M, Cassaing S, Fillaux J, Blancher A, Magnaval JF, Pipy B, Berry A. Cellular and cytokine changes in the alveolar environment among immunocompromised patients during Pneumocystis jirovecii infection. Med Mycol 2010; 48:1075-87. [PMID: 20470237 DOI: 10.3109/13693786.2010.484027] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Limited data exist on the cytokine and cellular changes in the alveolar environment in immunocompromised patients during Pneumocystis jirovecii infection. A cellular and a cytokine analysis were performed on bronchoalveolar lavage (BAL) samples from three groups of patients, i.e., an initial study group of 64 immunocompromised P. jirovecii-positive individuals and two control groups of P. jirovecii-negative patients who had been or not immunosuppressed (65 patients). The results were related to alveolar dilution as determined by urea measurement. Compared with non-infected groups, P. jirovecii-infected patients had a lower level of alveolar macrophages (AM), particularly those with high burdens of P. jirovecii. Alveolar macrophages over-expressed the Dectin-1 receptor, which was largely implicated in P. jirovecii clearance. The alveolar CD8+T and CD4+T lymphocyte counts were increased and an inverse correlation was observed between the alveolar CD4+ cell count and the P. jirovecii burden. Although the alveolar IL-6 level was considerably increased, alveolar IL-17, IL-10, TNF-α, TGF-β concentrations of P. jirovecii patients were not different from the control groups. Changes in the pulmonary environment were also highlighted during P. jirovecii colonization. Our study suggests that there is a correlation between the P. jirovecii burden in the alveolus (from colonization to a high P. jirovecii burden), and the degree of impairment of the alveolar immune response.
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Affiliation(s)
- Xavier Iriart
- Service de Parasitologie Mycologie, Centre Hospitalier Universitaire de Toulouse, H ô pital Rangueil, Toulouse, France.
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27
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Catherinot E, Lanternier F, Bougnoux ME, Lecuit M, Couderc LJ, Lortholary O. Pneumocystis jirovecii Pneumonia. Infect Dis Clin North Am 2010; 24:107-38. [PMID: 20171548 DOI: 10.1016/j.idc.2009.10.010] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Pneumocystis jirovecii has gained attention during the last decade in the context of the AIDS epidemic and the increasing use of cytotoxic and immunosuppressive therapies. This article summarizes current knowledge on biology, pathophysiology, epidemiology, diagnosis, prevention, and treatment of pulmonary P jirovecii infection, with a particular focus on the evolving pathophysiology and epidemiology. Pneumocystis pneumonia still remains a severe opportunistic infection, associated with a high mortality rate.
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Affiliation(s)
- Emilie Catherinot
- Université Paris Descartes, Service de Maladies Infectieuses et Tropicales, 149 Rue de Sèvres, Centre d'Infectiologie Necker-Pasteur, Hôpital Necker-Enfants Malades, Paris 75015, France
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28
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Abstract
Pneumocystis jirovecii is the opportunistic fungal organism that causes Pneumocystis pneumonia (PCP) in humans. Similar to other opportunistic pathogens, Pneumocystis causes disease in individuals who are immunocompromised, particularly those infected with HIV. PCP remains the most common opportunistic infection in patients with AIDS. Incidence has decreased greatly with the advent of HAART. However, an increase in the non-HIV immunocompromised population, noncompliance with current treatments, emergence of drug-resistant strains and rise in HIV(+) cases in developing countries makes Pneumocystis a pathogen of continued interest and a public health threat. A great deal of research interest has addressed therapeutic interventions to boost waning immunity in the host to prevent or treat PCP. This article focuses on research conducted during the previous 5 years regarding the host immune response to Pneumocystis, including innate, cell-mediated and humoral immunity, and associated immunotherapies tested against PCP.
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Affiliation(s)
- Michelle N Kelly
- Section of Pulmonary/Critical Care Medicine, LSU Health Sciences Center, Medical Education Building 3205, 1901 Perdido Street, New Orleans, LA 70112, USA.
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29
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The macrophage marches on its phagosome: dynamic assays of phagosome function. Nat Rev Immunol 2009; 9:594-600. [PMID: 19590530 DOI: 10.1038/nri2591] [Citation(s) in RCA: 132] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Professional phagocytes ingest particulate material to fulfil a diverse array of functions in a multicellular organism. The ancestral function of phagosomes is digestion; however, through evolution this degradative capacity has become pivotal to the adaptive immune response by processing antigens to be presented to lymphocytes. Moreover, phagocytes have also acquired an active role in microbial killing. This Innovation article describes new assays that probe the biological activities which occur within phagosomes. These assays provide functional insights into how the phagosome fulfils its diverse roles in homeostasis and in innate and adaptive immune responses.
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30
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Olivetta E, Mallozzi C, Ruggieri V, Pietraforte D, Federico M, Sanchez M. HIV-1 Nef induces p47(phox) phosphorylation leading to a rapid superoxide anion release from the U937 human monoblastic cell line. J Cell Biochem 2009; 106:812-22. [PMID: 19130504 DOI: 10.1002/jcb.22041] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The Nef protein of the human immunodeficiency virus type 1 (HIV-1) plays a crucial role in AIDS pathogenesis by modifying host cell signaling pathways. We investigated the effects of Nef on the NADPH oxidase complex, a key enzyme involved in the generation of reactive oxygen species during the respiratory burst in human monocyte/macrophages. We have recently shown that the inducible expression of HIV-1 Nef in human macrophages cell line modulates in bi-phasic mode the superoxide anion release by NADPH oxidase, inducing a fast increase of the superoxide production, followed by a delayed strong inhibition mediated by Nef-induced soluble factor(s). Our study is focused on the molecular mechanisms involved in Nef-mediated activation of NADPH oxidase and superoxide anion release. Using U937 cells stably transfected with different Nef alleles, we found that both Nef membrane localization and intact SH3-binding domain are needed to induce superoxide release. The lack of effect during treatment with a specific MAPK pathway inhibitor, PD98059, demonstrated that Nef-induced superoxide release is independent of Erk1/2 phosphorylation. Furthermore, Nef induced the phosphorylation and then the translocation of the cytosolic subunit of NADPH oxidase complex p47(phox) to the plasma membrane. Adding the inhibitor PP2 prevented this process, evidencing the involvement of the Src family kinases on Nef-mediated NADPH oxidase activation. In addition, LY294002, a specific inhibitor of phosphoinositide 3-kinase (PI3K) inhibited both the Nef-induced p47(phox) phosphorylation and the superoxide anion release. These data indicate that Nef regulates the NADPH oxidase activity through the activation of the Src kinases and PI3K.
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Affiliation(s)
- Eleonora Olivetta
- National AIDS Centre, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Roma, Italy
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31
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Linke MJ, Ashbaugh AA, Koch JV, Levin L, Tanaka R, Walzer PD. Effects of surfactant protein-A on the interaction of Pneumocystis murina with its host at different stages of the infection in mice. J Eukaryot Microbiol 2009; 56:58-65. [PMID: 19335775 DOI: 10.1111/j.1550-7408.2008.00363.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We examined the effects of surfactant protein A (SP-A), a collectin, on the interaction of Pneumocystis murina with its host at the beginning, early to middle, and late stages of infection. Pneumocystis murina from SP-A wild-type (WT) mice inoculated intractracheally into WT mice (WT(S)-WT(R)) adhered well to alveolar macrophages, whereas organisms from SP-A knockout (KO) mice inoculated into KO mice (KO(S)-KO(R)) did not. Substitution of WT mice as the source of organisms (WT(S)-KO(R)) or recipient host macrophages (KO(S)-WT(R)) restored adherence to that found with WT(S)-WT(R) mice. In contrast, when immunosuppressed KO and WT mice were inoculated with P. murina from a homologous source (KO(S)-KO(R), WT(S)-WT(R)) or heterologous source (WT(S)-KO(R), KO(S)-WT(R)) and followed sequentially, WT(S)-KO(R) mice had the highest levels of infection at weeks 3 and 4; these mice also had the highest levels of the chemokine macrophage inflammatory protein-2 and neutrophils in lavage fluid at week 3. Surfactant protein-A administered to immunosuppressed KO(S)-KO(R) mice with Pneumocystis pneumonia for 8 wk as a therapeutic agent failed to lower the organism burden. We conclude that SP-A can correct the host immune defect in the beginning of P. murina infection, but not in the middle or late stages of the infection.
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Affiliation(s)
- Michael J Linke
- Research Service, Department of Veterans Affairs Medical Center, Cincinnati, Ohio 45220, USA
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32
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Rappleye CA, Goldman WE. Fungal stealth technology. Trends Immunol 2008; 29:18-24. [DOI: 10.1016/j.it.2007.10.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2007] [Revised: 09/11/2007] [Accepted: 10/12/2007] [Indexed: 10/22/2022]
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Primary macrophages from HIV-infected adults show dysregulated cytokine responses to Salmonella, but normal internalization and killing. AIDS 2007; 21:2399-408. [PMID: 18025876 DOI: 10.1097/qad.0b013e3282f25107] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Adults with advanced HIV are susceptible to invasive and recrudescent infections with nontyphoidal salmonellae. OBJECTIVES To examine whether persistence and recurrence of salmonella infection results from HIV-related defects in macrophage internalization and intracellular killing or from ineffective type 1 cytokine responses. Such defects could be a direct consequence of macrophage HIV infection or secondary to reduced enhancement of macrophage effector functions by interferon-gamma (IFNgamma) as CD4 cell count falls. DESIGN Ex-vivo scientific case-control study. METHODS Primary ex-vivo human alveolar macrophages (huAM) from HIV-negative and HIV-positive subjects were challenged with Salmonella typhimurium under unprimed and IFNgamma-primed conditions to study internalization and intracellular killing of bacteria and cytokine responses of huAM. RESULTS Priming of huAM with IFNgamma reduced bacterial internalization but enhanced microbicidal activity against intracellular salmonellae. HuAM from HIV-positive subjects showed unimpaired internalization and intracellular killing of salmonellae, with and without IFNgamma priming. Opsonic and mannose receptor (CD206)-mediated entry was not required for optimal internalization. HuAM from HIV-positive subjects, however, exhibited increased secretion of tumour necrosis factor alpha (TNFalpha), interleukin (IL)-10 and IL-12 in response to S. typhimurium challenge, regardless of IFNgamma priming. This cytokine dysregulation showed a trend to a curvilinear relationship with peripheral CD4 cell count, with marked decline at values < 250 cell/mul. CONCLUSIONS Dysregulation of proinflammatory cytokine release, including IL-12, by macrophages during salmonella infection may underlie the susceptibility to severe salmonellosis in patients with AIDS. This defect was not reversed by IFNgamma and may represent a proinflammatory effect of HIV infection upon the macrophage or the alveolar milieu.
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Patel NR, Zhu J, Tachado SD, Zhang J, Wan Z, Saukkonen J, Koziel H. HIV Impairs TNF-α Mediated Macrophage Apoptotic Response toMycobacterium tuberculosis. THE JOURNAL OF IMMUNOLOGY 2007; 179:6973-80. [DOI: 10.4049/jimmunol.179.10.6973] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Lundborg M, Bouhafs R, Gerde P, Ewing P, Camner P, Dahlén SE, Jarstrand C. Aggregates of ultrafine particles modulate lipid peroxidation and bacterial killing by alveolar macrophages. ENVIRONMENTAL RESEARCH 2007; 104:250-7. [PMID: 17303107 DOI: 10.1016/j.envres.2007.01.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2006] [Revised: 12/19/2006] [Accepted: 01/04/2007] [Indexed: 05/14/2023]
Abstract
We hypothesized that aggregates of ultrafine carbon and washed diesel particles impair the ability of alveolar macrophages (AM) to kill bacteria and enhance the AM lipid peroxidation (LPO) of lung surfactant. Rat AM were exposed, 5h, to particles 20 microg/ml. The AM, containing carbon or washed diesel particles, were incubated 2h, with Streptococcus pneumoniae, an American Type Culture Collection (ATCC) strain or clinical isolates. Surviving bacteria were quantified. Surfactant was incubated, 5h, with carbon or washed diesel loaded AM and LPO was measured. The particle load was approximately 1 microg/10(6) AM, representing accepted exposure to ambient particles in Europe. Metal concentrations were 10 to 100 fold higher in washed diesel--than in carbon particles. There was a dose dependent increase in bacterial survival with carbon-loaded macrophages, but not with washed diesel-loaded AM. Clinical isolates had a higher survival rate with carbon-loaded macrophages than the ATCC strain. Surfactant LPO was increased with washed diesel-loaded macrophages (95%) and with carbon-loaded macrophages (55%) compared to controls. High LPO caused by washed diesel-loaded AM reflects their increased oxidative metabolism, probably caused by particle metals. The additional oxygen metabolites maintained bactericidal activity of AM, while corresponding activity was decreased in carbon-loaded AM. Altered functions of AM may explain health problems related to air pollution.
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Affiliation(s)
- Margot Lundborg
- Division of Physiology, The National Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
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Tachado SD, Zhang J, Zhu J, Patel N, Cushion M, Koziel H. Pneumocystis-mediated IL-8 release by macrophages requires coexpression of mannose receptors and TLR2. J Leukoc Biol 2006; 81:205-11. [PMID: 17020928 DOI: 10.1189/jlb.1005580] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Interaction with the unique fungus Pneumocystis (Pc) promotes IL-8 release by human alveolar macrophages (AM), although the receptor(s) mediating IL-8 release have not been identified. TLR2 recognizes fungal components and mediates release of host defense cytokines and chemokines, although whether TLR2 mediates signaling in response to Pc is not known. In the current study, Pc induced IL-8 release by human AM, and AM pretreatment with anti-TLR2 neutralizing antibody reduced IL-8 release. However, in nonphagocytic human embryonic kidney (HEK)293 cells transfected with human TLR2 cDNA, incubation with Pc did not induce IL-8 release, whereas these same cells released IL-8 in response to the TLR2 agonist lipoteichoic acid. Targeted gene silencing of AM mannose receptors (MR; phagocytic receptors for Pc) using small interfering RNA also reduced Pc-mediated IL-8 release in human AM. However, HEK293 cells transfected with human MR cDNA alone did not release IL-8 in response to Pc. In contrast, HEK293 cells cotransfected with human TLR2 and human MR cDNA released IL-8 in response to Pc. In human AM, Pc promoted direct interaction of MR and TLR2, IL-8 release was reduced markedly upon simultaneous blocking of TLR2 and gene silencing of MR, and IL-8 release was dependent in part on transcription factor NF-kappaB and ERK1/2 and JNK MAPKs. These studies demonstrate that Pc-mediated IL-8 release by human AM requires the coexpression of MR and TLR2 and further supports the concept that combinatorial interactions of macrophage innate receptors provide specificity of host defense cell responses to infectious challenge.
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Affiliation(s)
- Souvenir D Tachado
- Division of Pulmoary, Critical Care and Sleep Medicine, Department of Medicine, Kirstein Hall, Room E/KSB-23, Beth Israel Deaconess Medical Center and Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, USA
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Angelici E, Spezzano M, Vaccari S, Valentini SB, Romani R, Contini C, Canipari R. Urokinase plasminogen activator and TGF-β production in immunosuppressed patients with and without P. Jiroveci infection. Microb Pathog 2006; 41:1-9. [PMID: 16704917 DOI: 10.1016/j.micpath.2006.03.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2005] [Revised: 03/13/2006] [Accepted: 03/16/2006] [Indexed: 10/24/2022]
Abstract
Macrophages play a pivotal role in a host's defence against pulmonary infections. Macrophage functions are impaired in immunosuppressed (IS) patients, regardless of whether they are HIV-positive (HIV+) or -negative (HIV-). Several studies have indicated that urokinase plasminogen activator (uPA) and transforming growth factor beta (TGF-beta) are important factors in a host's defence against pulmonary pathogens. We measured uPA and TGF-beta activity in unstimulated peripheral blood monocytes (PBM) of both HIV-infected and non-infected IS patients with or without Pneumocystis jiroveci (formerly carinii) pneumonia (PCP). As previously found in alveolar macrophages (AMs), the majority of uPA activity was found in cell lysates. The highest values of uPA activity were found in control subjects. All the patients displayed a decreased production of uPA, irrespective of HIV infection. Similarly, active TGF-beta was higher in control subjects than in HIV+ and IS patients. The presence of P. jiroveci infection further lowered uPA and TGF-beta activity. Decreased TGF-beta activation might be a consequence of lower uPA production, which may, in turn, influence virus replication, since it has been demonstrated that TGF-beta can suppress human HIV expression in monocytes/macrophages. Further studies are warranted to elucidate whether the decrease in uPA and TGF-beta activity impairs a host's defence against P. jiroveci infection.
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Affiliation(s)
- Elena Angelici
- Department of Clinical Medicine, University La Sapienza, Rome, Italy
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Lasbury ME, Durant PJ, Ray CA, Tschang D, Schwendener R, Lee CH. Suppression of alveolar macrophage apoptosis prolongs survival of rats and mice with pneumocystis pneumonia. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2006; 176:6443-53. [PMID: 16709801 DOI: 10.4049/jimmunol.176.11.6443] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The number of alveolar macrophages is decreased in patients or animals with Pneumocystis pneumonia (Pcp). This loss of alveolar macrophages is in part due to apoptosis caused by Pneumocystis infection. The mechanism of apoptosis induction is unknown. Cell-free bronchoalveolar lavage fluids from Pneumocystis-infected rats or mice have the ability to induce apoptosis in normal alveolar macrophages. To characterize the mechanisms by which apoptosis proceeds in alveolar macrophages during Pcp, specific caspase inhibitors are tested for their ability to suppress the apoptosis. In vitro induction of apoptosis can be inhibited by the caspase-9 inhibitor (Z-LEHD-FMK) but not by the inhibitor to caspase-8 or -10. The caspase-9 inhibitor can also inhibit apoptosis of alveolar macrophages in vivo when it is intranasally instilled into dexamethasone-immunosuppressed, Pneumocystis-infected rats or L3T4 cell-depleted, Pneumocystis-infected mice. The number of alveolar macrophages rebounds in caspase-9 inhibitor-treated Pcp animals. Phagocytic activity of alveolar macrophages in treated animals is also recovered, and organism burden in these animals is reduced. Administration of caspase-9 inhibitor also clears the exudate that normally fills the alveoli during Pcp and decreases lung inflammation. Furthermore, caspase-9-treated Pcp animals survive for the entire 70-day period of the study, whereas nontreated Pcp animals die 40-60 days after initiation of infection. Depletion of recovered alveolar macrophages by intranasal administration of clodronate-containing liposomes in caspase-9 inhibitor-treated animals abrogates the effects of the inhibitor. Together, these results indicate that immunomodulation of the host response may be an alternative to current treatments for Pcp.
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Affiliation(s)
- Mark E Lasbury
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
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Olivetta E, Pietraforte D, Schiavoni I, Minetti M, Federico M, Sanchez M. HIV-1 Nef regulates the release of superoxide anions from human macrophages. Biochem J 2006; 390:591-602. [PMID: 15847608 PMCID: PMC1198939 DOI: 10.1042/bj20042139] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The NADPH oxidase enzymatic complex participates in the oxidative burst by producing ROS (reactive oxygen species). Altered levels of ROS production may have pathogenetic implications due to the loss of some innate immune functions such as oxidative burst and phagocytosis. Considering that HIV-1 Nef protein plays a primary role in AIDS pathogenesis, by affecting the immune system, we sought to dissect possible effects of Nef on the release of superoxide anions. We show here that the inducible expression of Nef in human phagocytic cells modulates the superoxide release in a biphasic manner. In particular, an early Nef-induced increase of the superoxide release was followed by a dramatic decrease starting from 10 h after the Nef induction. This was observed whatever the presence of cell activators such as GM-CSF (granulocyte/macrophage colony-stimulating factor) or fMLP (N-formyl-L-methionyl-L-leucyl-L-phenylalanine). Whereas the early increase in superoxide release is probably the result of the already described Nef-dependent activation of PAK-2 (p21-activated kinase 2)-Rac2, we were interested in investigating the mechanisms underlying the late inhibition of superoxide release observed originally. In this regard, we individuated at least three independent requirements for the Nef-induced blockade of superoxide release: (i) the active protein synthesis; (ii) both the membrane localization and the interaction with endocytotic machinery of Nef; and (iii) the release of soluble factor(s). Moreover, we observed that IL-10 (interleukin-10) inhibits superoxide release, whereas its depletion restored NADPH oxidase activity. We propose that the cell membrane-to-lysosome Nef transit leads to the synthesis and release of soluble factor(s) and, among them, IL-10 might significantly contribute to the inhibition of NAPDH oxidase activity.
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Affiliation(s)
- Eleonora Olivetta
- *Department of Infectious, Parasitic and Immune-mediated Diseases, Istituto Superiore di Sanità, viale Regina Elena 299, 00161 Rome, Italy
| | - Donatella Pietraforte
- †Department of Cell Biology and Neurosciences, Istituto Superiore di Sanità, viale Regina Elena 299, 00161 Rome, Italy
| | - Ilaria Schiavoni
- *Department of Infectious, Parasitic and Immune-mediated Diseases, Istituto Superiore di Sanità, viale Regina Elena 299, 00161 Rome, Italy
| | - Maurizio Minetti
- †Department of Cell Biology and Neurosciences, Istituto Superiore di Sanità, viale Regina Elena 299, 00161 Rome, Italy
| | - Maurizio Federico
- *Department of Infectious, Parasitic and Immune-mediated Diseases, Istituto Superiore di Sanità, viale Regina Elena 299, 00161 Rome, Italy
| | - Massimo Sanchez
- †Department of Cell Biology and Neurosciences, Istituto Superiore di Sanità, viale Regina Elena 299, 00161 Rome, Italy
- To whom correspondence should be addressed (email )
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Zhang J, Tachado SD, Patel N, Zhu J, Imrich A, Manfruelli P, Cushion M, Kinane TB, Koziel H. Negative regulatory role of mannose receptors on human alveolar macrophage proinflammatory cytokine release in vitro. J Leukoc Biol 2005; 78:665-74. [PMID: 16000387 DOI: 10.1189/jlb.1204699] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Alveolar macrophages (AM) are critical components of lung innate immunity and contribute to an effective host response to Pneumocystis pneumonia. Recognition of unopsonized Pneumocystis organisms by human AM is mediated predominantly via mannose receptors and results in phagocytosis, release of reactive oxygen species, and activation of the nuclear transcription factor (NF)-kappaB. However, the AM host defense genes activated by Pneumocystis have not been defined. In the present study, incubation of AM with unopsonized Pneumocystis organisms was not associated with release of interleukin (IL)-1beta, IL-6, or tumor necrosis factor (TNF)-alpha (important cytokines in the host response to Pneumocystis) and did not induce IL-1beta, IL-6, or TNF-alpha mRNA transcripts. These findings were not attributed to Pneumocystis-induced cytopathic changes, as these same AM released IL-8 and matrix metalloproteinase-9 in response to Pneumocystis. NF-kappaB-mediated IL-8 release was independent of Pneumocystis phagocytosis. The observed response was specific, as IL-1beta, IL-6, and TNF-alpha release and mRNA induction were preserved in response to lipopolysaccharide or serum-opsonized Pneumocystis. The absence of IL-1beta, IL-6, and TNF-alpha release in response to Pneumocystis was predominately influenced by AM mannose receptors, as blocking mannose receptors or targeted mannose receptor small interfering RNA functional gene silencing resulted in TNF-alpha release in response to unopsonized Pneumocystis organisms. Furthermore, ligation of AM mannose receptors by unopsonized Pneumocystis organisms reduced Toll-like receptor 4-mediated TNF-alpha release. Taken together, these data suggest that mannose receptors on human AM may suppress select proinflammatory cytokine release and may serve to regulate the innate inflammatory responses to infectious challenge in the lungs.
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MESH Headings
- Adolescent
- Adult
- Animals
- Cytokines/biosynthesis
- Feedback, Physiological/immunology
- Female
- Gene Silencing
- Humans
- In Vitro Techniques
- Interleukin-8/biosynthesis
- Interleukin-8/immunology
- Lectins, C-Type/genetics
- Lectins, C-Type/immunology
- Lipopolysaccharides/pharmacology
- Macrophages, Alveolar/drug effects
- Macrophages, Alveolar/immunology
- Macrophages, Alveolar/microbiology
- Male
- Mannose Receptor
- Mannose-Binding Lectins/genetics
- Mannose-Binding Lectins/immunology
- Matrix Metalloproteinase 9/biosynthesis
- Matrix Metalloproteinase 9/immunology
- Middle Aged
- NF-kappa B/immunology
- Pneumocystis/immunology
- Pulmonary Alveoli/immunology
- Rats
- Rats, Inbred Lew
- Rats, Inbred Strains
- Receptors, Cell Surface/genetics
- Receptors, Cell Surface/immunology
- Reference Values
- Tumor Necrosis Factor-alpha/biosynthesis
- Tumor Necrosis Factor-alpha/drug effects
- Tumor Necrosis Factor-alpha/immunology
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Affiliation(s)
- Jianmin Zhang
- Critical Care and Sleep Medicine, Kirstein Hall, Room E/KSB-23, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02215, USA
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41
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Craig S, Lopez A, Hoskin D, Markham F. Meconium inhibits phagocytosis and stimulates respiratory burst in alveolar macrophages. Pediatr Res 2005; 57:813-8. [PMID: 15774832 DOI: 10.1203/01.pdr.0000157724.02332.8b] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The meconium aspiration syndrome is an important cause of respiratory distress in newborn infants. Alveolar macrophages (AMs) provide a first line of defense in the lower respiratory tract against inhaled pathogens and particles such as meconium. In this study, we examined the effect of meconium on two primary macrophage functions: phagocytosis and respiratory burst. Short-term exposure of rat NR8383 AMs to sterile meconium from human or equine neonates (1.2-24 mg/mL) produced a dose-dependent decrease in phagocytosis of fluorescent latex beads. This effect was not due to decreased cell viability or to an elevation of intracellular cAMP. The effect of short-term exposure to meconium on the respiratory burst response in AMs was quantified using flow cytometry to measure oxidation of dichlorofluorescin diacetate. A robust respiratory burst was triggered when AMs were exposed to 12 or 24 mg/mL meconium. This effect was attenuated but not eliminated by filtration of the meconium. However, subsequent to meconium exposure, AMs had a reduced respiratory burst in response to stimulation with phorbol myristate acetate. In addition, AMs that were exposed to meconium for an extended period (24 h) showed DNA fragmentation indicative of apoptosis. Meconium therefore may interfere with AM function by inducing oxidative stress and apoptosis. Tissue injury from release of reactive oxygen species by AMs may be important in the pathophysiology of the meconium aspiration syndrome.
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Affiliation(s)
- Sylvia Craig
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia B3H 1X5, Canada.
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Linke M, Ashbaugh A, Koch J, Tanaka R, Walzer P. Surfactant protein A limits Pneumocystis murina infection in immunosuppressed C3H/HeN mice and modulates host response during infection. Microbes Infect 2005; 7:748-59. [PMID: 15857803 DOI: 10.1016/j.micinf.2005.01.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2004] [Revised: 01/19/2005] [Accepted: 01/26/2005] [Indexed: 12/31/2022]
Abstract
The development of Pneumocystis murina pneumonia and host response were characterized over time and at different levels of infection in corticosteroid immunosuppressed surfactant protein A (SP-A) knockout and wild-type (WT) mice. Infection increased over time in both strains of mice; however, significantly more cyst forms were detected in the knockout mice at intermediate and late stages of infection. In mice with heavy infections, TNF-alpha and IFN-gamma protein concentrations were significantly higher in pulmonary lavage fluid from knockout mice. There was a significant positive correlation between TNF-alpha and IFN-gamma concentrations and the level of infection in knockout mice, but not in WT mice. No significant differences were detected in IL-1 levels between the two strains of mice at any of the time points or at any level of infection. At heavier infection levels, significantly more MIP-2 protein was detected in the lungs of knockout mice, but a significant positive correlation between MIP-2 concentrations and the infection level was detected in both groups of mice. At the intermediate stage of infection, a significantly higher percentage of neutrophils was detected in the lungs of knockout mice than in WT mice. There was no difference in SP-D levels between WT and KO mice with identical levels of infection. These data support a protective role for SP-A in host defense against Pneumocystis and suggest that the effects of SP-A on the host response vary based on the intensity of the infection.
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Affiliation(s)
- Michael Linke
- Department of Veterans Affairs Medical Center, Research Service, 3200 Vine Street, Cincinnati, OH 45220, USA.
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Abstract
Species of the genus Pneumocystis exist as opportunistic fungal pathogens and are associated with severe pneumonia and pulmonary complications in immunocompromised individuals. Although prophylactic therapy for Pneumocystis has significantly decreased the overall incidence of infection, more than 80% of cases in current patient populations are considered breakthrough cases. In the HIV-infected population, in the years following the initiation of highly active antiretroviral therapy (HAART), significant reductions in the incidence of Pneumocystis infection were observed, although trends over the last several years suggest that the incidence of Pneumocystis has plateaued rather than decreased. Furthermore, with the more prominent usage of immunosuppressive therapies, the frequency of Pneumocystis infection in the HIV-negative population, such as those with hematologic malignancies and those who have undergone transplantation, has risen significantly. Investigating host defense mechanisms against P. carinii has historically been problematic due to the difficulty in achieving continuous in vitro propagation of proliferating Pneumocytis organisms. Nevertheless, clinical and experimental studies have documented that host defense against Pneumocystis involves a concerted effort between innate, cell-mediated (T lymphocyte) and humoral (B lymphocyte) responses. However, the pulmonary environment is a tissue site where heightened inflammatory responses can often lead to inflammation-mediated injury, thereby contributing to the pathogenesis of Pneumocystis infection. Accordingly, clearance of Pneumocystis from the pulmonary environment is dependent on a delicate equilibrium between the inflammatory response and immune-mediated clearance of the organism. Furthermore, innate and adaptive responses against Pneumocystis are strikingly similar to those against other medically-important fungi, thus providing additional evidence that Pneumocystis exists as a fungal organism.
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Affiliation(s)
- Chad Steele
- Department of Pediatrics, Division of Pulmonology Children's Hospital of Pittsburgh, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA.
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Hermann AC, Millard PJ, Blake SL, Kim CH. Development of a respiratory burst assay using zebrafish kidneys and embryos. J Immunol Methods 2004; 292:119-29. [PMID: 15350517 DOI: 10.1016/j.jim.2004.06.016] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2004] [Revised: 05/06/2004] [Accepted: 06/09/2004] [Indexed: 11/20/2022]
Abstract
The innate immune response constitutes the first line of defense against invading pathogens and consists of a variety of immune defense mechanisms including the respiratory burst of phagocytes. Respiratory burst can be used as a reliable measure of the immune response of a host, and numerous assays have been developed to measure this response in a variety of mammal and fish species. Phagocytes, like granulocytes and macrophages, that are derived from different tissues, or grown in cell culture, have been employed in a range of assay formats employing a variety of detection methods. The small size of the zebrafish has prevented the large-scale extraction of these cells for respiratory burst assays in the zebrafish. In this work, we describe a respiratory burst assay developed for the zebrafish using intact kidneys and embryos as sources of phagocytes. Phorbol myristate acetate (PMA)-inducible reactive oxygen species (ROS) were detected following the oxidation of a non-fluorescent dye 2',7'-dihydrodichlorofluorescein diacetate (H2DCFDA) to dichlorofluorescein (DCF), a fluorescent product. Embryos from 1 day post-fertilization until 5 days post-fertilization (dpf) were employed in this assay. Abrogation of H2DCFDA oxidation by the protein kinase C (PKC) inhibitor bisindolylmaleimide I (BisI) indicated a reduction in the respiratory burst. Fluorescence from the PMA-induced respiratory burst in kidneys and embryos was significantly elevated above DMSO-treated controls, while preincubation with BisI inhibited the increase in fluorescence. Colocalization of cell-associated chloromethyl-dihydrodichlorofluorescein diacetate (CM-H2DCFDA) with the phagocyte-selective dye neutral red is consistent with the observation that macrophages and granulocytes are the ROS-producing cells in the zebrafish.
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Affiliation(s)
- Andrea C Hermann
- Department of Biochemistry, Microbiology, and Molecular Biology, 5735 Hitchner Hall, University of Maine, Orono, ME 04469, USA
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45
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Zhang J, Zhu J, Imrich A, Cushion M, Kinane TB, Koziel H. Pneumocystis activates human alveolar macrophage NF-kappaB signaling through mannose receptors. Infect Immun 2004; 72:3147-60. [PMID: 15155616 PMCID: PMC415687 DOI: 10.1128/iai.72.6.3147-3160.2004] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Alveolar macrophages (AM) represent important effector cells in the innate immune response to the AIDS-related pathogen Pneumocystis, but the early AM host defense signaling events are poorly defined. Using AM from healthy individuals, we showed in the present study that Pneumocystis organisms stimulate AM NF-kappaB p50 and p65 nuclear translocation in a time-dependent and multiplicity-of-infection-dependent manner as determined by electrophoretic mobility shift assay and immunofluorescence microscopy and that NF-kappaB nuclear translocation is associated with I-kappaB phosphorylation. Importantly, competitive inhibition of mannose receptor and targeted short interfering RNA-mediated gene suppression of mannose receptor mRNA and protein is associated with complete elimination of NF-kappaB nuclear translocation in response to Pneumocystis. Furthermore, human immunodeficiency virus (HIV) infection of AM (as a model human disease state of reduced AM mannose receptor expression and function) inhibits Pneumocystis-mediated NF-kappaB nuclear translocation and is associated with reduced I-kappaB phosphorylation and reduced interleukin-8 (IL-8) release. In contrast, NF-kappaB nuclear translocation and IL-8 release in response to lipopolysaccharide are intact in AM from both healthy and HIV-infected individuals, indicating that the observed impairment is not a global disturbance of the NF-kappaB pathway. Thus, in addition to phagocytic and endocytic effector functions, the present study identifies mannose receptors as pattern recognition receptors capable of NF-kappaB activation in response to infectious non-self challenge. AM mannose receptor-mediated NF-kappaB activation may represent an important mechanism of the host cell response to Pneumocystis, and altered NF-kappaB activation in the context of HIV infection may impair a critical innate immune signaling response and may contribute to pathogenesis of opportunistic lung infections.
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Affiliation(s)
- Jianmin Zhang
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215, USA
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Steele C, Marrero L, Swain S, Harmsen AG, Zheng M, Brown GD, Gordon S, Shellito JE, Kolls JK. Alveolar macrophage-mediated killing of Pneumocystis carinii f. sp. muris involves molecular recognition by the Dectin-1 beta-glucan receptor. ACTA ACUST UNITED AC 2004; 198:1677-88. [PMID: 14657220 PMCID: PMC2194130 DOI: 10.1084/jem.20030932] [Citation(s) in RCA: 238] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Innate immune mechanisms against Pneumocystis carinii, a frequent cause of pneumonia in immunocompromised individuals, are not well understood. Using both real time polymerase chain reaction as a measure of organism viability and fluorescent deconvolution microscopy, we show that nonopsonic phagocytosis of P. carinii by alveolar macrophages is mediated by the Dectin-1 β-glucan receptor and that the subsequent generation of hydrogen peroxide is involved in alveolar macrophage–mediated killing of P. carinii. The macrophage Dectin-1 β-glucan receptor colocalized with the P. carinii cyst wall. However, blockage of Dectin-1 with high concentrations of anti–Dectin-1 antibody inhibited binding and concomitant killing of P. carinii by alveolar macrophages. Furthermore, RAW 264.7 macrophages overexpressing Dectin-1 bound P. carinii at a higher level than control RAW cells. In the presence of Dectin-1 blockage, killing of opsonized P. carinii could be restored through FcγRII/III receptors. Opsonized P. carinii could also be efficiently killed in the presence of FcγRII/III receptor blockage through Dectin-1–mediated phagocytosis. We further show that Dectin-1 is required for P. carinii–induced macrophage inflammatory protein 2 production by alveolar macrophages. Taken together, these results show that nonopsonic phagocytosis and subsequent killing of P. carinii by alveolar macrophages is dependent upon recognition by the Dectin-1 β-glucan receptor.
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Affiliation(s)
- Chad Steele
- Department of Pediatrics, Division of Pulmonology, Children's Hospital of Pittsburgh, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
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47
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Abstract
Pneumocystis jiroveci (P. carinii) is an opportunistic pathogen that has gained particular prominence since the onset of the AIDS epidemic. Among several important advances in diagnosis and management, appropriately targeting chemoprophylaxis to HIV-infected patients at high clinical risk for P. jiroveci pneumonia and the introduction of effective combination anti-retroviral therapy (including highly active antiretroviral therapy [HAART]) have contributed to the reduced incidence of P. jiroveci pneumonia. Despite the success of these clinical interventions, P. jiroveci pneumonia remains the most common opportunistic pneumonia and the most common life-threatening infectious complication in HIV-infected patients. Trimethoprim/sulfamethoxazole (cotrimoxazole) remains the first-line agent for effective therapy and chemoprophylaxis, and corticosteroids represent an important adjunctive agent in the treatment of moderate-to-severe P. jiroveci pneumonia. However, problems of chemoprophylaxis and treatment failures, high rates of adverse drug reactions and drug intolerance to first-line antimicrobials, high rates of relapse or recurrence with second-line agents, and newer concerns about the development of P. jiroveci drug resistance represent formidable challenges to the management and treatment of AIDS-related P. jiroveci pneumonia. With the expanding global problem of HIV infection, the intolerance or unavailability of HAART to many individuals and limited access to healthcare for HIV-infected patients, P. jiroveci pneumonia will remain a major worldwide problem in the HIV-infected population. New drugs under development as anti-Pneumocystis agents such as echinocandins and pneumocandins, which inhibit beta-glucan synthesis, or sordarins, which inhibit fungal protein synthesis, show promise as effective agents. Continued basic research into the biology and genetics of P. jiroveci and host defense response to P. jiroveci will allow the development of newer antimicrobials and immunomodulatory therapeutic agents to more effectively treat life-threatening pneumonia caused by this organism.
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Affiliation(s)
- Naimish Patel
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, 330 Brookline Avenue, Boston, MA 02115, USA
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48
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Swain SD, Lee SJ, Nussenzweig MC, Harmsen AG. Absence of the macrophage mannose receptor in mice does not increase susceptibility to Pneumocystis carinii infection in vivo. Infect Immun 2003; 71:6213-21. [PMID: 14573639 PMCID: PMC219593 DOI: 10.1128/iai.71.11.6213-6221.2003] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Host defense against the opportunistic pathogen Pneumocystis carinii requires functional interactions of many cell types. Alveolar macrophages are presumed to be a vital host cell in the clearance of P. carinii, and the mechanisms of this interaction have come under scrutiny. The macrophage mannose receptor is believed to play an important role as a receptor involved in the binding and phagocytosis of P. carinii. Although there is in vitro evidence for this interaction, the in vivo role of this receptor in P. carinii clearance in unclear. Using a mouse model in which the mannose receptor has been deleted, we found that the absence of this receptor is not sufficient to allow infection by P. carinii in otherwise immunocompetent mice. Furthermore, when mice were rendered susceptible to P. carinii by CD4(+) depletion, mannose receptor knockout mice (MR-KO) had pathogen loads equal to those of wild-type mice. However, the MR-KO mice exhibited a greater influx of phagocytes into the alveoli during infection. This was accompanied by increased pulmonary pathology in the MR-KO mice, as well as greater accumulation of glycoproteins in the alveoli (glycoproteins, including harmful hydrolytic enzymes, are normally cleared by the mannose receptor). We also found that the surface expression of the mannose receptor is not downregulated during P. carinii infection in wild-type mice. Our findings suggest that while the macrophage mannose receptor may be important in the recognition of P. carinii, in vivo, this mechanism may be redundant, and the absence of this receptor may be compensated for.
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Affiliation(s)
- Steve D Swain
- Department of Veterinary Molecular Biology, Montana State University, Bozeman, Montana 59717, USA.
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Yong SJ, Vuk-Pavlovic Z, Standing JE, Crouch EC, Limper AH. Surfactant protein D-mediated aggregation of Pneumocystis carinii impairs phagocytosis by alveolar macrophages. Infect Immun 2003; 71:1662-71. [PMID: 12654779 PMCID: PMC152070 DOI: 10.1128/iai.71.4.1662-1671.2003] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pneumocystis carinii remains an important and potentially fatal cause of opportunistic pneumonia. Animal studies reveal that substantial quantities of surfactant protein D (SP-D) accumulate in the airspaces during P. carinii pneumonia and are particularly abundant in aggregates of organisms. Due to the multimeric structure of SP-D, we hypothesized that SP-D mediates aggregation of the organism. From previous clinical studies it is known that aggregated organisms are conspicuous in sections of lung tissue and bronchoalveolar lavage (BAL) fluids of humans with active P. carinii pneumonia. Herein, we observe that SP-D levels increased at least fourfold in BAL fluids of patients with P. carinii pneumonia. Next, a spectrophotometric sedimentation assay was developed to assess the aggregation of P. carinii in vitro by SP-D. P. carinii organisms were first stripped with glutathione to remove bound SP-D and subsequently incubated in the presence of SP-D and 2 mM calcium. P. carinii incubated with natural SP-D (10 micro g/ml) containing dodecamers and higher-order forms exhibited aggregation and enhanced sedimentation compared to that of glutathione-stripped P. carinii. Aggregation was also enhanced by the concentrated supernatant of rat BAL fluid, and this effect was abolished by the selective removal of SP-D from the lavage fluid. P. carinii aggregation was reduced by maltose, mannose, and EDTA, consistent with the role of the SP-D C-type lectin domain (CRD) in the aggregation event. Comparisons of different molecular forms of SP-D showed that dodecamers-but not trimeric subunits-mediate optimal aggregation of P. carinii. Aggregation of P. carinii by SP-D was shown to be responsible for the impaired phagocytosis of the organisms by alveolar macrophages. Thus, SP-D-mediated aggregation of P. carinii may represent one means by which the organism avoids elimination by the host.
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Affiliation(s)
- Suk-Joong Yong
- Thoracic Diseases Research Unit, Division of Pulmonary, Critical Care, and Internal Medicine, 8-24 Stabile Building, Mayo Clinic, Rochester, MN 55905, USA
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50
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Abstract
Pulmonary macrophages with a key role in defence against respiratory infection are a heterogeneous family of cells with phagocytic, antigen processing and immunomodulatory functions. Macrophages are important in both innate and acquired immunity in the respiratory tract, and have a role in lung defence against viruses, bacteria, mycobacteria and fungi. Interactions of pathogens with lung macrophages is strongly influenced by soluble immune components including complement, collectins and immunoglobulins. Macrophage function can be modulated by cytokines, environmental exposures, recent and chronic infection including HIV infection, drug therapy and gene transfer.
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Affiliation(s)
- S B Gordon
- Wellcome Trust Research Laboratory, University of Malawi, Queen Elizabeth Central Hospital, Blantyre, Malawi
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