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Bias of the Immune Response to Pneumocystis murina Does Not Alter the Ability of Neonatal Mice to Clear the Infection. J Fungi (Basel) 2021; 7:jof7100827. [PMID: 34682248 PMCID: PMC8537783 DOI: 10.3390/jof7100827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 09/25/2021] [Accepted: 09/29/2021] [Indexed: 11/17/2022] Open
Abstract
Newborn mice are unable to clear Pneumocystis (PC) infection with the same efficiency as adults due, in part, to their inability to develop a robust immune response to infection until three weeks of age. It is known that infants tend develop a Th2 skewed response to antigen so we sought to determine whether a biased cytokine response altered the clearance of PC infection in neonatal mice. P. murina infection in neonatal mice resulted in increased IL-4 expression by CD4 T cells and myeloid cells, augmented IL-13 secretion within the airways and increased arginase activity in the airways, indicative of Th2-type responses. P. murina-infected IL-4Rα-/- neonates had a shift towards Th1 cytokine production and increased numbers of CD4 and CD8 T cells within the lung as well as elevated levels of P. murina-specific IgG. IFNγ-/- and IL-23 p19-/- mice had altered CD4-T cell-dependent cytokine and cell responses. Though we could alter the T helper cell environment in neonatal knockout mice, there was no loss in the ability of these pups to clear infection. It is possible that the Th2 phenotype normally seen in neonatal mice protects the developing lung from pro-inflammatory immune responses without compromising host defense against P. murina.
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2
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Gingerich AD, Norris KA, Mousa JJ. Pneumocystis Pneumonia: Immunity, Vaccines, and Treatments. Pathogens 2021; 10:pathogens10020236. [PMID: 33669726 PMCID: PMC7921922 DOI: 10.3390/pathogens10020236] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 02/11/2021] [Accepted: 02/16/2021] [Indexed: 12/18/2022] Open
Abstract
For individuals who are immunocompromised, the opportunistic fungal pathogen Pneumocystis jirovecii is capable of causing life-threatening pneumonia as the causative agent of Pneumocystis pneumonia (PCP). PCP remains an acquired immunodeficiency disease (AIDS)-defining illness in the era of antiretroviral therapy. In addition, a rise in non-human immunodeficiency virus (HIV)-associated PCP has been observed due to increased usage of immunosuppressive and immunomodulating therapies. With the persistence of HIV-related PCP cases and associated morbidity and mortality, as well as difficult to diagnose non-HIV-related PCP cases, an improvement over current treatment and prevention standards is warranted. Current therapeutic strategies have primarily focused on the administration of trimethoprim-sulfamethoxazole, which is effective at disease prevention. However, current treatments are inadequate for treatment of PCP and prevention of PCP-related death, as evidenced by consistently high mortality rates for those hospitalized with PCP. There are no vaccines in clinical trials for the prevention of PCP, and significant obstacles exist that have slowed development, including host range specificity, and the inability to culture Pneumocystis spp. in vitro. In this review, we overview the immune response to Pneumocystis spp., and discuss current progress on novel vaccines and therapies currently in the preclinical and clinical pipeline.
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Affiliation(s)
- Aaron D. Gingerich
- Center for Vaccines and Immunology, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA; (A.D.G.); (K.A.N.)
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
| | - Karen A. Norris
- Center for Vaccines and Immunology, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA; (A.D.G.); (K.A.N.)
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
| | - Jarrod J. Mousa
- Center for Vaccines and Immunology, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA; (A.D.G.); (K.A.N.)
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
- Correspondence:
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3
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Edey MM, Gunasekera PN, Lobb M, Imran M. Intravenous immunoglobulin as adjunctive therapy in kidney transplant recipients with severe pneumocystis pneumonia. Transpl Infect Dis 2020; 23:e13454. [PMID: 32869412 DOI: 10.1111/tid.13454] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 08/17/2020] [Accepted: 08/20/2020] [Indexed: 12/28/2022]
Abstract
Pneumocystis jirovecii is an opportunistic pathogen that may cause severe, life-threatening respiratory infections in immunocompromised patients such as those with kidney transplants. Although antimicrobial prophylaxis is now universally recommended in the early post-transplant period, Pneumocystis pneumonia (PCP) can occur later. If such infection occurs, mortality rates are high. Beyond standard therapy with trimethoprim-sulfamethoxazole, there is a lack of evidence-based options for intensifying treatment when initial therapy fails to show improvement. Moreover, it is usual to minimize immunosuppression in life-threatening infection, but graft damage may occur, particularly in kidney transplant recipients at above-average immunological risk. Here we present two cases of severe PCP in high immunological risk recipients who were managed with adjunctive intravenous immunoglobulin and withdrawal of immunosuppression. Both patients recovered and were discharged from hospital with functioning grafts.
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Affiliation(s)
- Matthew M Edey
- Department of Nephrology, Hull University Teaching Hospitals NHS Trust, Hull, UK.,Hull-York Medical School, Kingston-upon-Hull, UK
| | - Pumali N Gunasekera
- Department of Critical Care Medicine, Hull University Teaching Hospitals NHS Trust, Hull, UK
| | - Mark Lobb
- Department of Transplant and Cellular Immunology, St James's University Hospital, Leeds, UK
| | - Muhammad Imran
- Department of Nephrology, Hull University Teaching Hospitals NHS Trust, Hull, UK.,Hull-York Medical School, Kingston-upon-Hull, UK
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4
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Hoy Z, Wright TW, Elliott M, Malone J, Bhagwat S, Wang J, Gigliotti F. Combination Immunotherapy with Passive Antibody and Sulfasalazine Accelerates Fungal Clearance and Promotes the Resolution of Pneumocystis-Associated Immunopathogenesis. Infect Immun 2020; 88:e00640-19. [PMID: 31611280 PMCID: PMC6977122 DOI: 10.1128/iai.00640-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 10/10/2019] [Indexed: 12/31/2022] Open
Abstract
The pulmonary immune response protects healthy individuals against Pneumocystis pneumonia (PcP). However, the immune response also drives immunopathogenesis in patients who develop severe PcP, and it is generally accepted that optimal treatment requires combination strategies that promote fungal killing and also provide effective immunomodulation. The anti-inflammatory drug sulfasalazine programs macrophages for enhanced Pneumocystis phagocytosis and also suppresses PcP-related immunopathogenesis. Anti-Pneumocystis antibody opsonizes Pneumocystis organisms for greater phagocytosis and may also mask antigens that drive immunopathogenesis. Thus, we hypothesized that combining antibody and sulfasalazine would have the dual benefit of enhancing fungal clearance while dampening immunopathogenesis and allow the rescue of severe PcP. To model a clinically relevant treatment scenario in mice, therapeutic interventions were withheld until clear symptoms of pneumonia were evident. When administered individually, both passive antibody and sulfasalazine improved pulmonary function and enhanced Pneumocystis clearance to similar degrees. However, combination treatment with antibody and sulfasalazine produced a more rapid improvement, with recovery of body weight, a dramatic improvement in pulmonary function, reduced lung inflammation, and the rapid clearance of the Pneumocystis organisms. Accelerated fungal clearance in the combination treatment group was associated with a significant increase in macrophage phagocytosis of Pneumocystis Both passive antibody and sulfasalazine resulted in the suppression of Th1 cytokines and a marked increase in lung macrophages displaying an alternatively activated phenotype, which were enhanced by combination treatment. Our data support the concept that passive antibody and sulfasalazine could be an effective and specific adjunctive therapy for PcP, with the potential to accelerate fungal clearance while attenuating PcP-associated immunopathogenesis.
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Affiliation(s)
- Zachary Hoy
- Department of Pediatrics, Division of Infectious Diseases, University of Rochester Medical Center, Rochester, New York, USA
| | - Terry W Wright
- Department of Pediatrics, Division of Infectious Diseases, University of Rochester Medical Center, Rochester, New York, USA
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, USA
| | - Michael Elliott
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, USA
| | - Jane Malone
- Department of Pediatrics, Division of Infectious Diseases, University of Rochester Medical Center, Rochester, New York, USA
| | - Samir Bhagwat
- Department of Pediatrics, Division of Infectious Diseases, University of Rochester Medical Center, Rochester, New York, USA
| | - Jing Wang
- Department of Pediatrics, Division of Infectious Diseases, University of Rochester Medical Center, Rochester, New York, USA
| | - Francis Gigliotti
- Department of Pediatrics, Division of Infectious Diseases, University of Rochester Medical Center, Rochester, New York, USA
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, USA
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5
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Evans HM, Garvy BA. The trophic life cycle stage of Pneumocystis species induces protective adaptive responses without inflammation-mediated progression to pneumonia. Med Mycol 2019; 56:994-1005. [PMID: 29267980 DOI: 10.1093/mmy/myx145] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 11/22/2017] [Indexed: 12/28/2022] Open
Abstract
Pneumocystis species are fungal pathogens that cause pneumonia in immunocompromised hosts. Lung damage during Pneumocystis pneumonia is predominately due to the inflammatory immune response. Pneumocystis species have a biphasic life cycle. Optimal innate immune responses to Pneumocystis species are dependent on stimulation with the cyst life cycle stage. Conversely, the trophic life cycle stage broadly suppresses proinflammatory responses to multiple pathogen-associated molecular patterns (PAMPs), including β-1,3-glucan. Little is known about the contribution of these life cycle stages to the development of protective adaptive responses to Pneumocystis infection. Here we report that CD4+ T cells primed in the presence of trophic forms are sufficient to mediate clearance of trophic forms and cysts. In addition, primary infection with trophic forms is sufficient to prime B-cell memory responses capable of clearing a secondary infection with Pneumocystis following CD4+ T cell depletion. While trophic forms are sufficient for initiation of adaptive immune responses in immunocompetent mice, infection of immunocompromised recombination-activating gene 2 knockout (RAG2-/-) mice with trophic forms in the absence of cysts does not lead to the severe weight loss and infiltration of innate immune cells associated with the development of Pneumocystis pneumonia.
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Affiliation(s)
- Heather M Evans
- Department of Microbiology, Immunology, and Molecular Genetics
| | - Beth A Garvy
- Department of Microbiology, Immunology, and Molecular Genetics.,Division of Infectious Diseases, College of Medicine, University of Kentucky, Lexington, Kentucky
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Lambert L, Culley FJ. Innate Immunity to Respiratory Infection in Early Life. Front Immunol 2017; 8:1570. [PMID: 29184555 PMCID: PMC5694434 DOI: 10.3389/fimmu.2017.01570] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 11/01/2017] [Indexed: 01/09/2023] Open
Abstract
Early life is a period of particular susceptibility to respiratory infections and symptoms are frequently more severe in infants than in adults. The neonatal immune system is generally held to be deficient in most compartments; responses to innate stimuli are weak, antigen-presenting cells have poor immunostimulatory activity and adaptive lymphocyte responses are limited, leading to poor immune memory and ineffective vaccine responses. For mucosal surfaces such as the lung, which is continuously exposed to airborne antigen and to potential pathogenic invasion, the ability to discriminate between harmless and potentially dangerous antigens is essential, to prevent inflammation that could lead to loss of gaseous exchange and damage to the developing lung tissue. We have only recently begun to define the differences in respiratory immunity in early life and its environmental and developmental influences. The innate immune system may be of relatively greater importance than the adaptive immune system in the neonatal and infant period than later in life, as it does not require specific antigenic experience. A better understanding of what constitutes protective innate immunity in the respiratory tract in this age group and the factors that influence its development should allow us to predict why certain infants are vulnerable to severe respiratory infections, design treatments to accelerate the development of protective immunity, and design age specific adjuvants to better boost immunity to infection in the lung.
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Affiliation(s)
- Laura Lambert
- Faculty of Medicine, Respiratory Infections Section, National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Fiona J Culley
- Faculty of Medicine, Respiratory Infections Section, National Heart and Lung Institute, Imperial College London, London, United Kingdom
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Blount RJ, Daly KR, Fong S, Chang E, Grieco K, Greene M, Stone S, Balmes J, Miller RF, Walzer PD, Huang L. Effects of clinical and environmental factors on bronchoalveolar antibody responses to Pneumocystis jirovecii: A prospective cohort study of HIV+ patients. PLoS One 2017; 12:e0180212. [PMID: 28692651 PMCID: PMC5503245 DOI: 10.1371/journal.pone.0180212] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 06/12/2017] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Humoral immunity plays an important role against Pneumocystis jirovecii infection, yet clinical and environmental factors that impact bronchoalveolar antibody responses to P. jirovecii remain uncertain. METHODS From October 2008-December 2011 we enrolled consecutive HIV-infected adults admitted to San Francisco General Hospital (SFGH) who underwent bronchoscopy for suspected Pneumocystis pneumonia (PCP). We used local air quality monitoring data to assign ozone, nitrogen dioxide, and fine particulate matter exposures within 14 days prior to hospital admission. We quantified serum and bronchoalveolar lavage fluid (BALF) antibody responses to P. jirovecii major surface glycoprotein (Msg) recombinant constructs using ELISA. We then fit linear regression models to determine whether PCP and ambient air pollutants were associated with bronchoalveolar antibody responses to Msg. RESULTS Of 81 HIV-infected patients enrolled, 47 (58%) were diagnosed with current PCP and 9 (11%) had a prior history of PCP. The median CD4+ count was 51 cells/μl (IQR 15-129) and 44% were current smokers. Serum antibody responses to Msg were statistically significantly predictive of BALF antibody responses, with the exception of IgG responses to MsgC8 and MsgC9. Prior PCP was associated with increased BALF IgA responses to Msg and current PCP was associated with decreased IgA responses. For instance, among patients without current PCP, those with prior PCP had a median 73.2 U (IQR 19.2-169) IgA response to MsgC1 compared to a 5.00 U (3.52-12.6) response among those without prior PCP. Additionally, current PCP predicted a 22.5 U (95%CI -39.2, -5.82) lower IgA response to MsgC1. Ambient ozone within the two weeks prior to hospital admission was associated with decreased BALF IgA responses to Msg while nitrogen dioxide was associated with increased IgA responses. CONCLUSIONS PCP and ambient air pollutants were associated with BALF IgA responses to P. jirovecii in HIV-infected patients evaluated for suspected PCP.
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Affiliation(s)
- Robert J. Blount
- Division of Pulmonary and Critical Care Medicine, University of California, San Francisco, California, United States of America
- Division of Pediatric Pulmonology, University of California, San Francisco, California, United States of America
| | - Kieran R. Daly
- Division of Infectious Diseases, University of Cincinnati, Cincinnati, Ohio, United States of America
- Veterans Administration Medical Center, Cincinnati, Ohio, United States of America
| | - Serena Fong
- HIV/AIDS Division, San Francisco General Hospital, University of California, San Francisco, California, United States of America
| | - Emily Chang
- HIV/AIDS Division, San Francisco General Hospital, University of California, San Francisco, California, United States of America
| | - Katherine Grieco
- HIV/AIDS Division, San Francisco General Hospital, University of California, San Francisco, California, United States of America
| | - Meredith Greene
- HIV/AIDS Division, San Francisco General Hospital, University of California, San Francisco, California, United States of America
| | - Stephen Stone
- HIV/AIDS Division, San Francisco General Hospital, University of California, San Francisco, California, United States of America
| | - John Balmes
- Division of Pulmonary and Critical Care Medicine, University of California, San Francisco, California, United States of America
- Environmental Health Sciences, University of California, Berkeley, California, United States of America
| | - Robert F. Miller
- Research Department of Infection and Population Health, Institute of Epidemiology and Healthcare, University College London, London, United Kingdom
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Peter D. Walzer
- Division of Infectious Diseases, University of Cincinnati, Cincinnati, Ohio, United States of America
- Veterans Administration Medical Center, Cincinnati, Ohio, United States of America
| | - Laurence Huang
- Division of Pulmonary and Critical Care Medicine, University of California, San Francisco, California, United States of America
- HIV/AIDS Division, San Francisco General Hospital, University of California, San Francisco, California, United States of America
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8
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Fan H, Guo JY, Ma SL, Zhang N, An CL. Synthetic p55 tandem DNA vaccine against Pneumocystis carinii in rats. Microbiol Immunol 2017; 60:397-406. [PMID: 27185490 DOI: 10.1111/1348-0421.12386] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 04/26/2016] [Accepted: 05/09/2016] [Indexed: 11/30/2022]
Abstract
Pneumocystis spp. are opportunistic fungal pathogens that are closely associated with severe pneumonia and pulmonary complications in patients with impaired immunity. In this study, the antigenic epitopes of the gene encoding the 55 kDa antigen fragment of Pneumocystis (p55), which may play an important role in Pneumocystis pneumonia, were analyzed. A gene containing tandem variants of the p55 antigen was synthesized and named the tandem antigen gene (TAG). TAG's potential as a DNA vaccine was assessed in immunosuppressed rats. Immunization with p55-TAG DNA vaccine significantly reduced both the pathogen burden and lung-weight to body-weight ratios. Additionally, p55-TAG vaccination in immunosuppressed rats elicited both cell-mediated and humoral immunity.
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Affiliation(s)
- Hua Fan
- Department of Pathogen Biology, College of Basic Medical Sciences, China Medical University, Shenyang 110122, China
| | - Jiu-Ying Guo
- Department of Pathogen Biology, College of Basic Medical Sciences, China Medical University, Shenyang 110122, China
| | - Su-Li Ma
- Department of Pathogen Biology, College of Basic Medical Sciences, China Medical University, Shenyang 110122, China
| | - Nan Zhang
- Department of Pathogen Biology, College of Basic Medical Sciences, China Medical University, Shenyang 110122, China
| | - Chun-Li An
- Department of Pathogen Biology, College of Basic Medical Sciences, China Medical University, Shenyang 110122, China
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Immunization with Pneumocystis Cross-Reactive Antigen 1 (Pca1) Protects Mice against Pneumocystis Pneumonia and Generates Antibody to Pneumocystis jirovecii. Infect Immun 2017; 85:IAI.00850-16. [PMID: 28031260 DOI: 10.1128/iai.00850-16] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 12/19/2016] [Indexed: 11/20/2022] Open
Abstract
Pneumocystis pneumonia (PcP) is a life-threatening infection that affects immunocompromised individuals. Nearly half of all PcP cases occur in those prescribed effective chemoprophylaxis, suggesting that additional preventive methods are needed. To this end, we have identified a unique mouse Pneumocystis surface protein, designated Pneumocystis cross-reactive antigen 1 (Pca1), as a potential vaccine candidate. Mice were immunized with a recombinant fusion protein containing Pca1. Subsequently, CD4+ T cells were depleted, and the mice were exposed to Pneumocystis murina Pca1 immunization completely protected nearly all mice, similar to immunization with whole Pneumocystis organisms. In contrast, all immunized negative-control mice developed PcP. Unexpectedly, Pca1 immunization generated cross-reactive antibody that recognized Pneumocystis jirovecii and Pneumocystis carinii Potential orthologs of Pca1 have been identified in P. jirovecii Such cross-reactivity is rare, and our findings suggest that Pca1 is a conserved antigen and potential vaccine target. The evaluation of Pca1-elicited antibodies in the prevention of PcP in humans deserves further investigation.
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10
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Kling HM, Norris KA. Vaccine-Induced Immunogenicity and Protection Against Pneumocystis Pneumonia in a Nonhuman Primate Model of HIV and Pneumocystis Coinfection. J Infect Dis 2016; 213:1586-95. [PMID: 26823337 PMCID: PMC4837913 DOI: 10.1093/infdis/jiw032] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 01/20/2016] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND The ubiquitous opportunistic pathogen Pneumocystis jirovecii causes pneumonia in immunocompromised individuals, including human immunodeficiency virus (HIV)-infected individuals, and pulmonary colonization with P. jirovecii is believed to be a cofactor in the development of chronic obstructive pulmonary disease. There is no vaccine for P. jirovecii; however, most adults are seropositive, indicating natural immune priming to this pathogen. We have shown that humoral response to a recombinant subunit of the P. jirovecii protease kexin (KEX1) correlates with protection from P. jirovecii colonization and pneumonia. METHODS Here we evaluated the immunogenicity and protective capacity of the recombinant KEX1 peptide vaccine in a preclinical, nonhuman primate model of HIV-induced immunosuppression and Pneumocystis coinfection. RESULTS Immunization with KEX1 induced a robust humoral response remained at protective levels despite chronic simian immunodeficiency virus/HIV-induced immunosuppression. KEX1-immunized macaques were protected from Pneumocystis pneumonia, compared with mock-immunized animals (P= .047), following immunosuppression and subsequent natural, airborne exposure to Pneumocystis CONCLUSIONS These data support the concept that stimulation of preexisting immunological memory to Pneumocystis with a recombinant KEX1 vaccine prior to immunosuppression induces durable memory responses and protection in the context of chronic, complex immunosuppression.
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Affiliation(s)
- Heather M Kling
- Department of Immunology, University of Pittsburgh, Pennsylvania
| | - Karen A Norris
- Department of Immunology, University of Pittsburgh, Pennsylvania
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11
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Samuelson DR, de la Rua NM, Charles TP, Ruan S, Taylor CM, Blanchard EE, Luo M, Ramsay AJ, Shellito JE, Welsh DA. Oral Immunization of Mice with Live Pneumocystis murina Protects against Pneumocystis Pneumonia. THE JOURNAL OF IMMUNOLOGY 2016; 196:2655-65. [PMID: 26864029 DOI: 10.4049/jimmunol.1502004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 01/06/2016] [Indexed: 01/01/2023]
Abstract
Pneumocystis pneumonia is a major cause of morbidity and mortality in immunocompromised patients, particularly those infected with HIV. In this study, we evaluated the potential of oral immunization with live Pneumocystis to elicit protection against respiratory infection with Pneumocystis murina. C57BL/6 mice vaccinated with live P. murina using a prime-boost vaccination strategy were protected from a subsequent lung challenge with P. murina at 2, 7, 14, and 28 d postinfection even after CD4(+) T cell depletion. Specifically, vaccinated immunocompetent mice had significantly faster clearance than unvaccinated immunocompetent mice and unvaccinated CD4-depleted mice remained persistently infected with P. murina. Vaccination also increased numbers of CD4(+) T cells, CD8(+) T cells, CD19(+) B cells, and CD11b(+) macrophages in the lungs following respiratory infection. In addition, levels of lung, serum, and fecal P. murina-specific IgG and IgA were increased in vaccinated animals. Furthermore, administration of serum from vaccinated mice significantly reduced Pneumocystis lung burden in infected animals compared with control serum. We also found that the diversity of the intestinal microbial community was altered by oral immunization with P. murina. To our knowledge, our data demonstrate for the first time that an oral vaccination strategy prevents Pneumocystis infection.
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Affiliation(s)
- Derrick R Samuelson
- Section of Pulmonary/Critical Care and Allergy/Immunology, Department of Medicine, Louisiana State University Health Sciences Center, New Orleans, LA 70112
| | - Nicholas M de la Rua
- Section of Pulmonary/Critical Care and Allergy/Immunology, Department of Medicine, Louisiana State University Health Sciences Center, New Orleans, LA 70112
| | - Tysheena P Charles
- Section of Pulmonary/Critical Care and Allergy/Immunology, Department of Medicine, Louisiana State University Health Sciences Center, New Orleans, LA 70112
| | - Sanbao Ruan
- Section of Pulmonary/Critical Care and Allergy/Immunology, Department of Medicine, Louisiana State University Health Sciences Center, New Orleans, LA 70112
| | - Christopher M Taylor
- Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA 70112; and
| | - Eugene E Blanchard
- Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA 70112; and
| | - Meng Luo
- Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA 70112; and
| | - Alistair J Ramsay
- Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA 70112; and Louisiana Vaccine Center, Louisiana State University Health Sciences Center, New Orleans, LA 70112
| | - Judd E Shellito
- Section of Pulmonary/Critical Care and Allergy/Immunology, Department of Medicine, Louisiana State University Health Sciences Center, New Orleans, LA 70112; Louisiana Vaccine Center, Louisiana State University Health Sciences Center, New Orleans, LA 70112
| | - David A Welsh
- Section of Pulmonary/Critical Care and Allergy/Immunology, Department of Medicine, Louisiana State University Health Sciences Center, New Orleans, LA 70112;
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12
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Opata MM, Hollifield ML, Lund FE, Randall TD, Dunn R, Garvy BA, Feola DJ. B Lymphocytes Are Required during the Early Priming of CD4+ T Cells for Clearance of Pneumocystis Infection in Mice. THE JOURNAL OF IMMUNOLOGY 2015; 195:611-20. [PMID: 26041535 DOI: 10.4049/jimmunol.1500112] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 05/12/2015] [Indexed: 11/19/2022]
Abstract
B cells play a critical role in the clearance of Pneumocystis. In addition to production of Pneumocystis-specific Abs, B cells are required during the priming phase for CD4(+) T cells to expand normally and generate memory. Clearance of Pneumocystis was found to be dependent on Ag specific B cells and on the ability of B cells to secrete Pneumocystis-specific Ab, as mice with B cells defective in these functions or with a restricted BCR were unable to control Pneumocystis infection. Because Pneumocystis-specific antiserum was only able to partially protect B cell-deficient mice from infection, we hypothesized that optimal T cell priming requires fully functional B cells. Using adoptive transfer and B cell depletion strategies, we determined that optimal priming of CD4(+) T cells requires B cells during the first 2-3 d of infection and that this was independent of the production of Ab. T cells that were removed from Pneumocystis-infected mice during the priming phase were fully functional and able to clear Pneumocystis infection upon adoptive transfer into Rag1(-/-) hosts, but this effect was ablated in mice that lacked fully functional B cells. Our results indicate that T cell priming requires a complete environment of Ag presentation and activation signals to become fully functional in this model of Pneumocystis infection.
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Affiliation(s)
- Michael M Opata
- Division of Infectious Diseases, Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY 40536
| | - Melissa L Hollifield
- Division of Infectious Diseases, Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY 40536
| | - Frances E Lund
- Department of Microbiology, The University of Alabama at Birmingham, Birmingham, AL 35294
| | - Troy D Randall
- Department of Medicine, The University of Alabama at Birmingham, Birmingham, AL 35294
| | - Robert Dunn
- Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121; and
| | - Beth A Garvy
- Division of Infectious Diseases, Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY 40536;
| | - David J Feola
- Department of Pharmacy Practice and Science, University of Kentucky College of Pharmacy, Lexington, KY 40536
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13
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Abstract
Pneumonia due to the fungus Pneumocystis jirovecii is a life-threatening infection that occurs in immunocompromised patients. The inability to culture the organism as well as the lack of an annotated genome has hindered antigen discovery that could be useful in developing novel vaccine- or antibody-based therapies as well as diagnostics for this infection. Here we report a novel method of surface proteomics analysis of Pneumocystis murina that reliably detected putative surface proteins that are conserved in Pneumocystis jirovecii. This technique identified novel CD4(+) T-cell epitopes as well as a novel B-cell epitope, Meu10, which encodes a glycosylphosphatidylinositol (GPI)-anchored protein thought to be involved in ascospore assembly. The described technique should facilitate the discovery of novel target proteins for diagnostics and therapeutics for Pneumocystis infection.
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Blount RJ, Djawe K, Daly KR, Jarlsberg LG, Fong S, Balmes J, Miller RF, Walzer PD, Huang L. Ambient air pollution associated with suppressed serologic responses to Pneumocystis jirovecii in a prospective cohort of HIV-infected patients with Pneumocystis pneumonia. PLoS One 2013; 8:e80795. [PMID: 24236202 PMCID: PMC3827464 DOI: 10.1371/journal.pone.0080795] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Accepted: 10/07/2013] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Ambient air pollution (AAP) may be associated with increased risk for Pneumocystis pneumonia (PCP). The mechanisms underlying this association remain uncertain. OBJECTIVES To determine if real-life exposures to AAP are associated with suppressed IgM antibody responses to P. jirovecii in HIV-infected (HIV+) patients with active PCP, and to determine if AAP, mediated by suppressed serologic responses to Pneumocystis, is associated with adverse clinical outcomes. METHODS We conducted a prospective cohort study in HIV+ patients residing in San Francisco and admitted to San Francisco General Hospital with microscopically confirmed PCP. Our AAP predictors were ambient air concentrations of particulate matter of < 10 µm in diameter (PM10) and < 2.5 µm in diameter (PM2.5), nitrogen dioxide (NO2), ozone (O3), and sulfur dioxide (SO2) measured immediately prior to hospital admission and 2 weeks prior to admission. Our primary outcomes were the IgM serologic responses to four recombinant P. jirovecii major surface glycoprotein (Msg) constructs: MsgC1, MsgC3, MsgC8, and MsgC9. RESULTS Elevated PM10 and NO2 exposures immediately prior to and two weeks prior to hospital admission were associated with decreased IgM antibody responses to P. jirovecii Msg. For exposures immediately prior to admission, every 10 µg/m(3) increase in PM10 was associated with a 25 to 35% decrease in IgM responses to Msg (statistically significant for all the Msg constructs), and every 10 ppb increase in NO2 was associated with a 19-45% decrease in IgM responses to Msg (statistically significant for MsgC8 and MsgC9). Similar findings were seen with exposures two weeks prior to admission, but for fewer of the Msg constructs. CONCLUSIONS Real life exposures to PM10 and NO2 were associated with suppressed IgM responses to P. jirovecii Msg in HIV+ patients admitted with PCP, suggesting a mechanism of immunotoxicity by which AAP increases host susceptibility to pulmonary infection.
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Affiliation(s)
- Robert J. Blount
- Division of Pulmonary and Critical Care Medicine, San Francisco General Hospital, University of California San Francisco, San Francisco, California, United States of America
- * E-mail:
| | - Kpandja Djawe
- Department of Internal Medicine, Division of Infectious Diseases, University of Cincinnati, Cincinnati, Ohio, United States of America
- Department of Environmental Health, Division of Epidemiology and Biostatistics, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - Kieran R. Daly
- Department of Internal Medicine, Division of Infectious Diseases, University of Cincinnati, Cincinnati, Ohio, United States of America
- Veterans Administration Medical Center, Cincinnati, Ohio, United States of America
| | - Leah G. Jarlsberg
- Division of Pulmonary and Critical Care Medicine, San Francisco General Hospital, University of California San Francisco, San Francisco, California, United States of America
| | - Serena Fong
- HIV/AIDS Division, San Francisco General Hospital, University of California San Francisco, San Francisco, California, United States of America
| | - John Balmes
- Division of Pulmonary and Critical Care Medicine, San Francisco General Hospital, University of California San Francisco, San Francisco, California, United States of America
- School of Public Health, University of California Berkeley, Berkeley, California, United States of America
| | - Robert F. Miller
- Research Department of Infection and Population Health, Institute of Epidemiology and Healthcare, University College London, London, United Kingdom
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Peter D. Walzer
- Department of Internal Medicine, Division of Infectious Diseases, University of Cincinnati, Cincinnati, Ohio, United States of America
- Department of Environmental Health, Division of Epidemiology and Biostatistics, University of Cincinnati, Cincinnati, Ohio, United States of America
- Veterans Administration Medical Center, Cincinnati, Ohio, United States of America
| | - Laurence Huang
- Division of Pulmonary and Critical Care Medicine, San Francisco General Hospital, University of California San Francisco, San Francisco, California, United States of America
- HIV/AIDS Division, San Francisco General Hospital, University of California San Francisco, San Francisco, California, United States of America
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Alveolar macrophages in neonatal mice are inherently unresponsive to Pneumocystis murina infection. Infect Immun 2012; 80:2835-46. [PMID: 22665378 DOI: 10.1128/iai.05707-11] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Pneumocystis pneumonia was first diagnosed in malnourished children and has more recently been found in children with upper respiratory symptoms. We previously reported that there is a significant delay in the immune response in newborn mice infected with Pneumocystis compared to adults (Garvy BA, Harmsen AG, Infect. Immun. 64:3987-3992, 1996, and Garvy BA, Qureshi M, J. Immunol. 165:6480-6486, 2000). This delay is characterized by the failure of neonatal lungs to upregulate proinflammatory cytokines and attract T cells into the alveoli. Here, we report that regardless of the age at which we infected the mice, they failed to mount an inflammatory response in the alveolar spaces until they were 21 days of age or older. Anti-inflammatory cytokines had some role in dampening inflammation, since interleukin-10 (IL-10)-deficient pups cleared Pneumocystis faster than wild-type pups and the neutralization of transforming growth factor beta (TGF-β) with specific antibody enhanced T cell migration into the lungs at later time points. However, the clearance kinetics were similar to those of control pups, suggesting that there is an intrinsic deficiency in the ability of innate immunity to control Pneumocystis. We found, using an adoptive transfer strategy, that the lung environment contributes to association of Pneumocystis organisms with alveolar macrophages, implying no intrinsic deficiency in the binding of Pneumocystis by neonatal macrophages. Using both in vivo and in vitro assays, we found that Pneumocystis organisms were less able to stimulate translocation of NF-κB to the nucleus of alveolar macrophages from neonatal mice. These data indicate that there is an early unresponsiveness of neonatal alveolar macrophages to Pneumocystis infection that is both intrinsic and related to the immunosuppressive environment found in neonatal lungs.
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Abstract
With increases in the immunocompromised patient population and aging of the HIV+ population, the risk of serious fungal infections and their complications will continue to rise. In these populations, infection with the fungal opportunistic pathogen Pneumocystis jirovecii remains a leading cause of morbidity and mortality. Infection with Pneumocystis (Pc) has been shown to be associated with the development of chronic obstructive pulmonary disease (COPD) in human subjects with and without HIV infection and in non-human primate models of HIV infection. In human studies and in a primate model of HIV/Pc co-infection, we have shown that antibody response to the Pc protein, kexin (KEX1), correlates with protection from colonization, Pc pneumonia, and COPD. These findings support the hypothesis that immunity to KEX1 may be critical to controlling Pc colonization and preventing or slowing development of COPD.
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Affiliation(s)
- Karen A Norris
- Department of Immunology, University of Pittsburgh School of Medicine, E 1057 Biomedical Science Tower, Pittsburgh, PA 15261, USA.
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17
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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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Wang J, Gigliotti F, Bhagwat SP, George TC, Wright TW. Immune modulation with sulfasalazine attenuates immunopathogenesis but enhances macrophage-mediated fungal clearance during Pneumocystis pneumonia. PLoS Pathog 2010; 6:e1001058. [PMID: 20808846 PMCID: PMC2924364 DOI: 10.1371/journal.ppat.1001058] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Accepted: 07/22/2010] [Indexed: 11/18/2022] Open
Abstract
Although T cells are critical for host defense against respiratory fungal infections, they also contribute to the immunopathogenesis of Pneumocystis pneumonia (PcP). However, the precise downstream effector mechanisms by which T cells mediate these diverse processes are undefined. In the current study the effects of immune modulation with sulfasalazine were evaluated in a mouse model of PcP-related Immune Reconstitution Inflammatory Syndrome (PcP-IRIS). Recovery of T cell-mediated immunity in Pneumocystis-infected immunodeficient mice restored host defense, but also initiated the marked pulmonary inflammation and severe pulmonary function deficits characteristic of IRIS. Sulfasalazine produced a profound attenuation of IRIS, with the unexpected consequence of accelerated fungal clearance. To determine whether macrophage phagocytosis is an effector mechanism of T cell-mediated Pneumocystis clearance and whether sulfasalazine enhances clearance by altering alveolar macrophage phagocytic activity, a novel multispectral imaging flow cytometer-based method was developed to quantify the phagocytosis of Pneumocystis in vivo. Following immune reconstitution, alveolar macrophages from PcP-IRIS mice exhibited a dramatic increase in their ability to actively phagocytose Pneumocystis. Increased phagocytosis correlated temporally with fungal clearance, and required the presence of CD4(+) T cells. Sulfasalazine accelerated the onset of the CD4(+) T cell-dependent alveolar macrophage phagocytic response in PcP-IRIS mice, resulting in enhanced fungal clearance. Furthermore, sulfasalazine promoted a TH2-polarized cytokine environment in the lung, and sulfasalazine-enhanced phagocytosis of Pneumocystis was associated with an alternatively activated alveolar macrophage phenotype. These results provide evidence that macrophage phagocytosis is an important in vivo effector mechanism for T cell-mediated Pneumocystis clearance, and that macrophage phenotype can be altered to enhance phagocytosis without exacerbating inflammation. Immune modulation can diminish pulmonary inflammation while preserving host defense, and has therapeutic potential for the treatment of PcP-related immunopathogenesis.
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Affiliation(s)
- Jing Wang
- Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States of America
| | - Francis Gigliotti
- Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States of America
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States of America
| | - Samir P. Bhagwat
- Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States of America
| | | | - Terry W. Wright
- Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States of America
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States of America
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19
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Relationship of Pneumocystis jiroveci humoral immunity to prevention of colonization and chronic obstructive pulmonary disease in a primate model of HIV infection. Infect Immun 2010; 78:4320-30. [PMID: 20660609 DOI: 10.1128/iai.00507-10] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Pulmonary colonization by the opportunistic pathogen Pneumocystis jiroveci is common in HIV(+) subjects and has been associated with development of chronic obstructive pulmonary disease (COPD). Host and environmental factors associated with colonization susceptibility are undefined. Using a simian-human immunodeficiency virus (SHIV) model of HIV infection, the immunologic parameters associated with natural Pneumocystis jiroveci transmission were evaluated. SHIV-infected macaques were exposed to P. jiroveci by cohousing with immunosuppressed, P. jiroveci-colonized macaques in two independent experiments. Serial plasma and bronchoalveolar lavage (BAL) fluid samples were examined for changes in antibody titers to recombinant Pneumocystis-kexin protein (KEX1) and evidence of Pneumocystis colonization by nested PCR of BAL fluid. In experiment 1, 10 of 14 monkeys became Pneumocystis colonized (Pc(+)) by 8 weeks post-SHIV infection, while 4 animals remained Pneumocystis colonization negative (Pc(-)) throughout the study. In experiment 2, 11 of 17 animals became Pneumocystis colonized by 16 weeks post-SHIV infection, while 6 monkeys remained Pc(-). Baseline plasma KEX1-IgG titers were significantly higher in monkeys that remained Pc(-), compared to Pc(+) monkeys, in experiments 1 (P = 0.013) and 2 (P = 0.022). Pc(-) monkeys had greater percentages of Pneumocystis-specific memory B cells after SHIV infection compared to Pc(+) monkeys (P = 0.037). After SHIV infection, Pc(+) monkeys developed progressive obstructive pulmonary disease, whereas Pc(-) monkeys maintained normal lung function throughout the study. These results demonstrate a correlation between the KEX1 humoral response and the prevention of Pneumocystis colonization and obstructive lung disease in the SHIV model. In addition, these results indicate that an effective Pneumocystis-specific memory B-cell response is maintained despite progressive loss of CD4(+) T cells during SHIV infection.
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20
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Kling HM, Shipley TW, Patil S, Morris A, Norris KA. Pneumocystis colonization in immunocompetent and simian immunodeficiency virus-infected cynomolgus macaques. J Infect Dis 2009; 199:89-96. [PMID: 19014344 DOI: 10.1086/595297] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Pneumocystis (Pc) colonization is common among human immunodeficiency virus (HIV)-infected subjects, although the clinical consequences of Pc carriage are not fully understood. We examined the frequency of asymptomatic carriage in healthy and simian immunodeficiency virus (SIV)-infected cynomolgus macaques by use of polymerase chain reaction (PCR) and assessment of changes in the serologic response to a recombinant fragment of the Pc protein kexin (KEX1). Anti-KEX1 antibodies were detected in 95% of healthy monkeys. To create a model of natural transmission of Pc, SIV-infected monkeys were cohoused with macaques coinfected with SIV and Pc. Pc colonization occurred when the CD4(+) T cell count decreased to <500 cells/microL, despite anti-Pc prophylaxis with trimethoprim-sulfamethoxazole. Increases in anti-KEX1 antibody titers preceded detection of Pc DNA in bronchoalveolar lavage (BAL) fluid samples by use of PCR. These results demonstrate the usefulness of recombinant KEX1 in serologic studies of Pc colonization and will improve the understanding of Pc transmission and clinical consequences of Pc colonization in HIV-infected patients.
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Affiliation(s)
- Heather M Kling
- Department of Immunology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA
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21
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22
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Hollifield M, Bou Ghanem E, de Villiers WJS, Garvy BA. Scavenger receptor A dampens induction of inflammation in response to the fungal pathogen Pneumocystis carinii. Infect Immun 2007; 75:3999-4005. [PMID: 17548480 PMCID: PMC1951997 DOI: 10.1128/iai.00393-07] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Alveolar macrophages are the effector cells largely responsible for clearance of Pneumocystis carinii from the lungs. Binding of organisms to beta-glucan and mannose receptors has been shown to stimulate phagocytosis of the organisms. To further define the mechanisms used by alveolar macrophages for clearance of P. carinii, mice deficient in the expression of scavenger receptor A (SRA) were infected with P. carinii, and clearance of organisms was monitored over time. SRA-deficient (SRAKO) mice consistently cleared P. carinii faster than did wild-type control mice. Expedited clearance corresponded to elevated numbers of activated CD4(+) T cells in the alveolar spaces of SRAKO mice compared to wild-type mice. Alveolar macrophages from SRAKO mice had increased expression of CD11b on their surfaces, consistent with an activated phenotype. However, they were not more phagocytic than macrophages expressing SRA, as measured by an in vivo phagocytosis assay. SRAKO alveolar macrophages produced significantly more tumor necrosis factor alpha (TNF-alpha) than wild-type macrophages when stimulated with lipopolysaccharide in vitro but less TNF-alpha in response to P. carinii in vitro. However, upon in vivo stimulation, SRAKO mice produced significantly more TNF-alpha, interleukin 12 (IL-12), and IL-18 in response to P. carinii infection than did wild-type mice. Together, these data indicate that SRA controls inflammatory cytokines produced by alveolar macrophages in the context of P. carinii infection.
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Affiliation(s)
- Melissa Hollifield
- University of Kentucky Chandler Medical Center, 800 Rose Street, Lexington, KY 40536-0298, USA
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23
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Empey KM, Hollifield M, Garvy BA. Exogenous heat-killed Escherichia coli improves alveolar macrophage activity and reduces Pneumocystis carinii lung burden in infant mice. Infect Immun 2007; 75:3382-93. [PMID: 17485459 PMCID: PMC1932967 DOI: 10.1128/iai.00174-07] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Pneumocystis carinii is an opportunistic fungal pathogen that causes life-threatening pneumonia in immunocompromised individuals. Infants appear to be particularly susceptible to Pneumocystis pulmonary infections. We have previously demonstrated that there is approximately a 3-week delay in the clearance of Pneumocystis organisms from pup mouse lungs compared to that in adults. We have further shown that there is approximately a 1-week delay in alveolar macrophage activation in pups versus adult mice. Alveolar macrophages are the primary effector cells responsible for the killing and clearance of Pneumocystis, suggesting that pup alveolar macrophages may be involved in the delayed clearance of this organism. Alveolar macrophages cultured in vitro with Pneumocystis alone demonstrate little to no activation, as indicated by a lack of cytokine production. However, when cultured with lipopolysaccharide (LPS) or zymosan, cytokine production was markedly increased, suggesting that pup alveolar macrophages are specifically unresponsive to Pneumocystis organisms rather than being intrinsically unable to become activated. Furthermore, pup mice treated with aerosolized, heat-killed Escherichia coli in vivo were able to clear Pneumocystis more efficiently than were control mice. Together, these data suggest that while pup alveolar macrophages are unresponsive to P. carinii f. sp. muris organisms, they are capable of activation by heat-killed E. coli in vivo, as well as LPS and zymosan in vitro. The lack of response of pup mice to P. carinii f. sp. muris may reflect protective mechanisms specific to the developing pup lung, but ultimately it results in insufficient clearance of Pneumocystis organisms.
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Affiliation(s)
- Kerry M Empey
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky Medical Center, 800 Rose Street, Lexington, KY 40536-0298, USA
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Larsen HH, von Linstow ML, Lundgren B, Høgh B, Westh H, Lundgren JD. Primary pneumocystis infection in infants hospitalized with acute respiratory tract infection. Emerg Infect Dis 2007; 13:66-72. [PMID: 17370517 PMCID: PMC2725833 DOI: 10.3201/eid1301.060315] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Acquisition of Pneumocystis jirovecii infection early in life has been confirmed by serologic studies. However, no evidence of clinical illness correlated with the primary infection has been found in immunocompetent children. We analyzed 458 nasopharyngeal aspirates from 422 patients hospitalized with 431 episodes of acute respiratory tract infection (RTI) by using a real-time PCR assay. In 68 episodes in 67 infants, P. jirovecii was identified. The odds ratio (95% confidence interval) of a positive signal compared with the first quartile of age (7-49 days) was 47.4 (11.0-203), 8.7 (1.9-39.7), and 0.6 (0.1-6.7) for infants in the second (50-112 days), third (113-265 days), and fourth (268-4,430 days) age quartiles, respectively. Infants with an episode of upper RTI (URTI) were 2.0 (1.05-3.82) times more likely to harbor P. jirovecii than infants with a lower RTI. P. jirovecii may manifest itself as a self-limiting URTI in infants, predominantly those 1.5-4 months of age.
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25
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Keely SP, Linke MJ, Cushion MT, Stringer JR. Pneumocystis murina MSG gene family and the structure of the locus associated with its transcription. Fungal Genet Biol 2007; 44:905-19. [PMID: 17320432 PMCID: PMC2063445 DOI: 10.1016/j.fgb.2007.01.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2006] [Revised: 12/26/2006] [Accepted: 01/03/2007] [Indexed: 11/20/2022]
Abstract
Analysis of the Pneumocystis murina MSG gene family and expression-site locus showed that, as in Pneumocystis carinii, P. murina MSG genes are arranged in head-to-tail tandem arrays located on multiple chromosomes, and that a variety of MSG genes can reside at the unique P. murina expression site. Located between the P. murina expression site and attached MSG gene is a block of 132 basepairs that is also present at the beginning of MSG genes that are not at the expression site. The center of this sequence block resembles the 28 basepair CRJE of P. carinii, but the block of conserved sequence in P. murina is nearly five times longer than in P. carinii, and much shorter than in P. wakefieldiae. These data indicate that the P. murina expression-site locus has a distinct structure.
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Affiliation(s)
- Scott P Keely
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH 45220, USA
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26
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Gigliotti F, Crow EL, Bhagwat SP, Wright TW. Sensitized CD8+ T cells fail to control organism burden but accelerate the onset of lung injury during Pneumocystis carinii pneumonia. Infect Immun 2006; 74:6310-6. [PMID: 16940142 PMCID: PMC1695514 DOI: 10.1128/iai.00668-06] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
While CD8+ cells have been shown to contribute to lung injury during Pneumocystis carinii pneumonia (PCP), there are conflicting reports concerning the ability of CD8+ cells to kill P. carinii. To address these two issues, we studied the effect of the presence of CD8+ cells in two mouse models of PCP. In the reconstituted SCID mouse model, depletion of CD8+ cells in addition to CD4+ cells after reconstitution did not result in increased numbers of P. carinii cysts compared to the numbers of cysts in mice with only CD4+ cells depleted. This result was observed regardless of whether the mice were reconstituted with naïve or P. carinii-sensitized lymphocytes. In contrast, reconstitution with sensitized lymphocytes resulted in more rapid onset of lung injury that was dependent on the presence of CD8+ cells. The course of organism replication over a 6-week period was also examined in the CD4+-T-cell-depleted and CD4+- and CD8+-T-cell-depleted mouse model of PCP. Again, the organism burdens were identical at all times regardless of whether CD8+ cells were present. Thus, in the absence of CD4+ T cells, CD8+ T cells are a key contributor to the inflammatory lung injury associated with PCP. However, we were unable to demonstrate an in vivo effect of these cells on the course of P. carinii infection.
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Affiliation(s)
- Francis Gigliotti
- Department of Pediatrics, University of Rochester School of Medicine & Dentistry, 601 Elmwood Avenue, Box 690, Rochester, NY 14642, USA.
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Abstract
Innate and adaptive immune responses target pathogenic fungi and provide defense against fungal infections. Recent studies demonstrate that specific host receptors recognize ligands that are unique to fungi and activate signaling cascades that lead to phagocytosis of fungi, generation of pro-inflammatory mediators, formation of reactive oxygen species, trafficking of inflammatory cells to sites of infection, and initiation of adaptive immune responses. Greater understanding of the molecular mechanisms that underlie antifungal defense has provided a framework for the investigation of protective vaccines and strategies for therapeutic adoptive cell transfer.
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Affiliation(s)
- Tobias M Hohl
- Infectious Diseases Service, Department of Medicine, Sloan-Kettering Institute, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA
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28
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Winkelstein JA, Marino MC, Lederman HM, Jones SM, Sullivan K, Burks AW, Conley ME, Cunningham-Rundles C, Ochs HD. X-linked agammaglobulinemia: report on a United States registry of 201 patients. Medicine (Baltimore) 2006; 85:193-202. [PMID: 16862044 DOI: 10.1097/01.md.0000229482.27398.ad] [Citation(s) in RCA: 352] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
X-linked agammaglobulinemia (XLA) is a primary immunodeficiency caused by mutations in the gene for Bruton tyrosine kinase (BTK) that result in the deficient development of B lymphocytes and hypogammaglobulinemia. Because the disorder is uncommon, no single institution has had sufficient numbers of patients to develop a comprehensive clinical picture of the disorder. Accordingly, a national registry of United States residents with XLA was established in 1999 to provide an updated clinical view of the disorder in a large cohort of patients. A total of 201 patients were registered by 66 physicians. The estimated birth rate for the 10-year period of 1988-1997 was 1/379,000. Infection was the most common initial clinical presentation (85%), followed by a positive family history (41%) and neutropenia (11%). Although the average age of diagnosis was younger in patients with a positive family history (mean, 2.59 yr) than in patients with a negative family history (mean, 5.37 yr) (p < 0.001), only 34.5% of patients with a positive family history at the time of their birth were diagnosed before clinical symptoms developed-that is, based on family history alone. Seventy percent of patients had at least 1 episode of otitis, 62% at least 1 episode of pneumonia, 60% at least 1 episode of sinusitis, 23% at least 1 episode of chronic/recurrent diarrhea, 21% at least 1 episode of conjunctivitis, 18% at least 1 episode of pyoderma and/or cellulitis, 11% at least 1 episode of meningitis/encephalitis, 10% at least 1 episode of sepsis, 8% at least 1 episode of septic arthritis, 6% at least 1 episode of hepatitis, and 3% at least 1 episode of osteomyelitis. Fourteen of 201 (6.9%) patients were dead at the time they were entered in the Registry. However, in a prospective 4 /4-year follow-up of living patients, only 3/80 (3.75%) patients died. Causes of death included disseminated enterovirus infection (n = 6), pulmonary insufficiency (n = 5), adenovirus infection (n = 1), sepsis (n = 1), acquired immunodeficiency disease syndrome (AIDS) (n = 1), myocarditis (n = 1), hepatitis (n = 2), and stem cell transplantation (n = 1).
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Affiliation(s)
- Jerry A Winkelstein
- From United States Immune Deficiency Network (JAW, MCM, CCR, HDO), the Immune Deficiency Foundation (JAW, MCM), the Johns Hopkins University School of Medicine (JAW, HML), the University of Arkansas for Medical Sciences (SMJ, AWB), the University of Pennsylvania School of Medicine (KS), the University of Tennessee School of Medicine (MEC), the Mt Sinai School of Medicine (CCR), and the University of Washington School of Medicine (HDO)
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Hung CY, Seshan KR, Yu JJ, Schaller R, Xue J, Basrur V, Gardner MJ, Cole GT. A metalloproteinase of Coccidioides posadasii contributes to evasion of host detection. Infect Immun 2005; 73:6689-703. [PMID: 16177346 PMCID: PMC1230962 DOI: 10.1128/iai.73.10.6689-6703.2005] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Coccidioides posadasii is a fungal respiratory pathogen of humans that can cause disease in immunocompetent individuals. Coccidioidomycosis ranges from a mild to a severe infection. It is frequently characterized either as a persistent disease that requires months to resolve or as an essentially asymptomatic infection that can reactivate several years after the original insult. In this report we describe a mechanism by which the pathogen evades host detection during the pivotal reproductive (endosporulation) phase of the parasitic cycle. A metalloproteinase (Mep1) secreted during endospore differentiation digests an immunodominant cell surface antigen (SOWgp) and prevents host recognition of endospores during the phase of development when these fungal cells are most vulnerable to phagocytic cell defenses. C57BL/6 mice were immunized with recombinant SOWgp and then challenged with a mutant strain of C. posadasii in which the MEP1 gene was disrupted. The animals showed a significant increase in percent survival compared to SOWgp-immune mice challenged with the parental strain. To explain these results, we proposed that retention of SOWgp on the surfaces of endospores of the mutant strain in the presence of high titers of antibody to the immunodominant antigen contributes to opsonization, increased phagocytosis, and killing of the fungal cells. In vitro studies of the interaction between a murine alveolar macrophage cell line and parasitic cells coated with SOWgp showed that the addition of anti-SOWgp antibody could enhance phagocytosis and killing of Coccidioides. We suggest that Mep1 plays a pivotal role as a pathogenicity determinant during coccidioidal infections and contributes to the ability of the pathogen to persist within the mammalian host.
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Affiliation(s)
- Chiung-Yu Hung
- Department of Medical Microbiology and Immunology, Medical College of Ohio, Toledo, 43614-5806, USA
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