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Wang J, Zhang ZQ, Gigliotti F, Wright TW. IFN-γ Limits Immunopathogenesis but Delays Fungal Clearance during Pneumocystis Pneumonia. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2023; 211:1397-1405. [PMID: 37721419 PMCID: PMC10635584 DOI: 10.4049/jimmunol.2300460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 08/29/2023] [Indexed: 09/19/2023]
Abstract
High levels of IFN-γ are produced in the lung during an adaptive immune response to Pneumocystis, but the effects of this prototypical Th1 cytokine on fungal clearance and immunopathogenesis have not been fully defined. Therefore, Pneumocystis-infected immunodeficient mice were immune reconstituted and administered control or anti-IFN-γ neutralizing Ab to determine how IFN-γ regulates the balance between host defense and immune-mediated lung injury. Mice treated with anti-IFN-γ demonstrated an initial worsening of Pneumocystis pneumonia-related immunopathogenesis, with greater weight loss, heightened lung inflammation, and more severe pulmonary function deficits than control mice. However, IFN-γ neutralization also enhanced macrophage phagocytosis of Pneumocystis and accelerated fungal clearance. When anti-IFN-γ-treated mice were also given IL-4 and IL-13 to promote a Th2-biased lung environment, the accelerated fungal clearance was preserved, but the severity of immunopathogenesis was reduced, and a more rapid recovery was observed. A direct suppressive effect of IFN-γ on macrophages was required but was not solely responsible for delayed fungal clearance, suggesting that IFN-γ acts through multiple mechanisms that likely include modulation of both macrophage and Th polarization. Enhanced Pneumocystis clearance in anti-IFN-γ-treated and IFN-γR-deficient mice was associated with significantly elevated IL-17+ CD4+ T cells and IL-17 protein in the lungs. Furthermore, neutralization of IL-17, but not IL-4, signaling blocked the accelerated fungal clearance observed in anti-IFN-γ-treated mice. Together, these data demonstrate that although IFN-γ delays fungal clearance by suppressing the lung Th17 response, it also serves an important regulatory role that limits immunopathogenesis and preserves pulmonary function.
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Affiliation(s)
- Jing Wang
- Department of Pediatrics, University of Rochester School of Medicine and Dentistry Rochester, NY 14642
| | - Zhuo-Qian Zhang
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry Rochester, NY 14642
| | - Francis Gigliotti
- Department of Pediatrics, University of Rochester School of Medicine and Dentistry Rochester, NY 14642
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry Rochester, NY 14642
| | - Terry W. Wright
- Department of Pediatrics, University of Rochester School of Medicine and Dentistry Rochester, NY 14642
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry Rochester, NY 14642
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2
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Zhang NN, Huang X, Feng HY, Huang LN, Xia JG, Wang Y, Zhang Y, Wu XJ, Li M, Cui W, Zhan QY. Circulating and Pulmonary T-cell Populations Driving the Immune Response in Non-HIV Immunocompromised Patients with Pneumocystis jirovecii Pneumonia. Int J Med Sci 2019; 16:1221-1230. [PMID: 31588187 PMCID: PMC6775264 DOI: 10.7150/ijms.34512] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 07/17/2019] [Indexed: 12/15/2022] Open
Abstract
Background: Previous studies in human subjects have mostly been confined to peripheral blood lymphocytes for Pneumocystis infection. We here aimed to compare circulating and pulmonary T-cell populations derived from human immunodeficiency virus (HIV)-uninfected immunocompromised patients with Pneumocystis jirovecii pneumonia (PCP) in order to direct new therapies. Methods: Peripheral blood and bronchoalveolar lavage samples were collected from patients with and without PCP. Populations of Th1/Tc1, Th2/Tc2, Th9/Tc9, and Th17/Tc17 CD4+ and CD8+ T cells were quantified using multiparameter flow cytometry. Results: No significant differences were found between PCP and non-PCP groups in circulating T cells. However, significantly higher proportions of pulmonary Th1 and Tc9 were observed in the PCP than in the non-PCP group. Interestingly, our data indicated that pulmonary Th1 was negatively correlated with disease severity, whereas pulmonary Tc9 displayed a positive correlation in PCP patients. Conclusions: Our findings suggest that pulmonary expansion of Th1 and Tc9 subsets may play protective and detrimental roles in PCP patients, respectively. Thus, these specific T-cell subsets in the lungs may serve as targeted immunotherapies for patients with PCP.
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Affiliation(s)
- Nan-Nan Zhang
- Center for Respiratory Diseases, China-Japan Friendship Hospital, Beijing 100029, China.,Department of Pulmonary and Critical Care Medicine, China-Japan Friendship Hospital, Beijing 100029, China.,National Clinical Research Center for Respiratory Diseases, Beijing 100029, China.,Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Xu Huang
- Center for Respiratory Diseases, China-Japan Friendship Hospital, Beijing 100029, China.,Department of Pulmonary and Critical Care Medicine, China-Japan Friendship Hospital, Beijing 100029, China.,National Clinical Research Center for Respiratory Diseases, Beijing 100029, China
| | - Hui-Ying Feng
- Center for Respiratory Diseases, China-Japan Friendship Hospital, Beijing 100029, China.,Department of Pulmonary and Critical Care Medicine, China-Japan Friendship Hospital, Beijing 100029, China.,National Clinical Research Center for Respiratory Diseases, Beijing 100029, China.,Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Lin-Na Huang
- Center for Respiratory Diseases, China-Japan Friendship Hospital, Beijing 100029, China.,Department of Pulmonary and Critical Care Medicine, China-Japan Friendship Hospital, Beijing 100029, China.,National Clinical Research Center for Respiratory Diseases, Beijing 100029, China
| | - Jin-Gen Xia
- Center for Respiratory Diseases, China-Japan Friendship Hospital, Beijing 100029, China.,Department of Pulmonary and Critical Care Medicine, China-Japan Friendship Hospital, Beijing 100029, China.,National Clinical Research Center for Respiratory Diseases, Beijing 100029, China
| | - Yan Wang
- Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Yi Zhang
- Center for Respiratory Diseases, China-Japan Friendship Hospital, Beijing 100029, China.,Department of Pulmonary and Critical Care Medicine, China-Japan Friendship Hospital, Beijing 100029, China.,National Clinical Research Center for Respiratory Diseases, Beijing 100029, China
| | - Xiao-Jing Wu
- Center for Respiratory Diseases, China-Japan Friendship Hospital, Beijing 100029, China.,Department of Pulmonary and Critical Care Medicine, China-Japan Friendship Hospital, Beijing 100029, China.,National Clinical Research Center for Respiratory Diseases, Beijing 100029, China
| | - Min Li
- Center for Respiratory Diseases, China-Japan Friendship Hospital, Beijing 100029, China.,Department of Pulmonary and Critical Care Medicine, China-Japan Friendship Hospital, Beijing 100029, China.,National Clinical Research Center for Respiratory Diseases, Beijing 100029, China
| | - Wei Cui
- Beijing Key Laboratory of Remodeling-Related Cardiovascular Diseases, Beijing Anzhen Hospital of Capital Medical University, Beijing Institute of Heart Lung and Blood Vessel Diseases, Beijing 100029, China
| | - Qing-Yuan Zhan
- Center for Respiratory Diseases, China-Japan Friendship Hospital, Beijing 100029, China.,Department of Pulmonary and Critical Care Medicine, China-Japan Friendship Hospital, Beijing 100029, China.,National Clinical Research Center for Respiratory Diseases, Beijing 100029, China
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3
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B cell production of tumor necrosis factor in response to Pneumocystis murina infection in mice. Infect Immun 2013; 81:4252-60. [PMID: 24002064 DOI: 10.1128/iai.00744-13] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pneumocystis species are opportunistic fungal pathogens that induce tumor necrosis factor (TNF) production by alveolar macrophages. Here we report that B cells from the draining lymph nodes as well as lung CD4(+) T cells are important producers of TNF upon Pneumocystis murina infection. To determine the importance of B cell-derived TNF in the primary response to P. murina, we generated bone marrow chimeras whose B cells were unable to produce TNF. The lung P. murina burden at 10 days postinfection in TNF knockout (TNFKO) chimeras was significantly higher than that in wild-type (WT) chimeras, which corresponded to reduced numbers of activated CD4(+) T cells in the lungs at this early time point. Furthermore, CD4(+) T cells isolated from P. murina-infected TNFKO chimeras were unable to stimulate clearance of P. murina upon adoptive transfer to recombinase-deficient (RAG1KO) hosts. Together, these data indicate that B cell-derived TNF plays an important function in promoting CD4(+) T cell expansion and production of TNF and facilitating protection against P. murina infection.
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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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5
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Bhagwat SP, Gigliotti F, Xu H, Wright TW. Contribution of T cell subsets to the pathophysiology of Pneumocystis-related immunorestitution disease. Am J Physiol Lung Cell Mol Physiol 2006; 291:L1256-66. [PMID: 16891394 PMCID: PMC4161614 DOI: 10.1152/ajplung.00079.2006] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Immune-mediated lung injury is an important component of Pneumocystis pneumonia (PcP)-related immunorestitution disease (IRD). However, the individual contribution of CD4(+) and CD8(+) T cells to the pathophysiology of IRD remains undetermined. Therefore, IRD was modeled in severe combined immunodeficient mice, and specific T cell depletion was used to determine how T cell subsets interact to affect the nature and severity of disease. CD4(+) cells were more abundant than CD8(+) cells during the acute stage of IRD that coincided with impaired pulmonary physiology and organism clearance. Conversely, CD8(+) cells were more abundant during the resolution phase following P. carinii clearance. Depletion of CD4(+) T cells protected mice from the acute pathophysiology of IRD. However, these mice could not clear the infection and developed severe PcP at later time points when a pathological CD8(+) T cell response was observed. In contrast, mice depleted of CD8(+) T cells efficiently cleared the infection but developed more severe disease, an increased frequency of IFN-gamma-producing CD4(+) cells, and a prolonged CD4(+) T cell response than mice with both CD4(+) and CD8(+) cells. These data suggest that CD4(+) T cells mediate the acute respiratory disease associated with IRD. In contrast, CD8(+) T cells contributed to neither lung injury nor organism clearance when CD4(+) cells were present, but instead served to modulate CD4 function. In the absence of CD4(+) cells, CD8(+) T cells produced a nonprotective, pathological immune response. These data suggest that the interplay of CD4(+) and CD8(+) T cells affects the ultimate outcome of PcP-related IRD.
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Affiliation(s)
- Samir P. Bhagwat
- Department of Pediatrics, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, NY 14642
| | - Francis Gigliotti
- Department of Pediatrics, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, NY 14642
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue Rochester, NY 14642
| | - Haodong Xu
- Department of Pathology and Laboratory Medicine, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, NY 14642
| | - Terry W. Wright
- Department of Pediatrics, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, NY 14642
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue Rochester, NY 14642
- Corresponding Author: Terry W. Wright, Ph.D., Department of Pediatrics, P.O. Box 850, University of Rochester School of Medicine and Dentistry, 601 Elmwood Ave., Rochester, NY 14642., TEL: (585) 275-4246, FAX: (585) 756-7780,
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6
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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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7
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Bruckner L, Gigliotti F, Wright T, Harmsen A, Notter RH, Chess P, Wang Z, Finkelstein J. Pneumocystis carinii infection sensitizes lung to radiation-induced injury after syngeneic marrow transplantation: role of CD4+ T cells. Am J Physiol Lung Cell Mol Physiol 2006; 290:L1087-96. [PMID: 16399785 DOI: 10.1152/ajplung.00441.2005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A murine model of bone marrow transplant (BMT)-related lung injury was developed to study how infection sensitizes lung to the damaging effects of total body irradiation (TBI) at infectious and TBI doses that individually do not cause injury. Mice infected with Pneumocystis carinii exhibited an asymptomatic, rapid, and transient influx of eosinophils and T cells in bronchoalveolar lavage fluid (BALF). In contrast, mice infected with P. carinii 7 days before receiving TBI and syngeneic BMT (P. carinii/TBI mice) exhibited severe pulmonary dysfunction, surfactant aggregate depletion, and surfactant activity reductions at 17 days post-BMT. BALF from P. carinii/TBI mice contained a disproportionate initial influx of CD4(+) T cells (CD4(+):CD8(+) ratio of 2.7) that correlated with progressive lung injury (from 8 to 17 days post-BMT). Levels of TNF-alpha in BALF were significantly increased in P. carinii/TBI mice compared with mice given either insult alone, with peak values found at 11 days post-BMT. In vivo depletion of CD4(+) T cells in P. carinii/TBI mice abrogated pulmonary dysfunction and reduced TNF-alpha levels in BALF, whereas depletion of CD8(+) T cells did not affect lung compliance or TNF-alpha. Lung injury was not attributable to direct P. carinii damage, since CD4-depleted P. carinii/TBI mice that exhibited no injury had higher average lung P. carinii burdens than either mice given P. carinii alone or undepleted P. carinii/TBI mice. Together, these results indicate that P. carinii infection can sensitize the lung to subsequent TBI-mediated lung injury via a process dependent on non-alloreactive CD4(+) T cells.
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Affiliation(s)
- Lauren Bruckner
- Division of Hematology/Oncology/Bone Marrow Transplant, Department of Pediatrics, University of Rochester Medical Center, 601 Elmwood Ave., Rochester, NY 14642, USA.
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8
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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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9
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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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10
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Kumar RK, Herbert C, Webb DC, Li L, Foster PS. Effects of anticytokine therapy in a mouse model of chronic asthma. Am J Respir Crit Care Med 2004; 170:1043-8. [PMID: 15306533 DOI: 10.1164/rccm.200405-681oc] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The relative contribution of Th2 and Th1 cytokines to the pathogenesis of lesions of chronic asthma remains poorly understood. To date, therapeutic inhibition of Th2 cytokines has proved disappointing. We used a clinically relevant model of chronic allergic asthma in mice to compare the effects of administering neutralizing antibodies to interleukin (IL)-13, IL-5, and interferon-gamma (IFN-gamma) to animals with established disease. As has been observed in clinical studies, anti-IL-5 inhibited both inflammation and remodeling but had no effect on airway responsiveness to methacholine. Anti-IL-13 effectively suppressed eosinophil recruitment and accumulation of chronic inflammatory cells in the airways. This treatment also partially suppressed changes of airway wall remodeling, including goblet cell hyperplasia/metaplasia and subepithelial fibrosis, but had limited ability to inhibit airway hyperreactivity (AHR). In contrast, treatment with anti-IFN-gamma markedly suppressed AHR. This antibody inhibited accumulation of chronic inflammatory cells but did not affect eosinophil recruitment or changes of remodeling. We conclude that inhibition of IL-5 is beneficial and that inhibition of IL-13 has considerable potential as a therapeutic strategy in chronic asthma, that IFN-gamma may play an important role in the pathogenesis of AHR, and that co-operative interaction between Th2 and Th1 cytokines contributes to the pathogenesis of the lesions of chronic asthma.
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Affiliation(s)
- Rakesh K Kumar
- Department of Pathology, University of New South Wales, Sydney, Australia.
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11
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Thomas CF, Vohra PK, Park JG, Puri V, Limper AH, Kottom TJ. Pneumocystis carinii BCK1 functions in a mitogen-activated protein kinase cascade regulating fungal cell-wall assembly. FEBS Lett 2003; 548:59-68. [PMID: 12885408 DOI: 10.1016/s0014-5793(03)00730-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Pneumocystis pneumonia remains the most common AIDS-defining opportunistic infection in people with HIV. The process by which Pneumocystis carinii constructs its cell wall is not well known, although recent studies reveal that molecules such as beta-1-3-glucan synthetase (GSC1) and environmental pH-responsive genes such as PHR1 are important for cell-wall integrity. In closely related fungi, a specific mitogen-activated protein kinase (MAPK) cascade regulates cell-wall assembly in response to elevated temperature. The upstream mitogen-activated protein kinase kinase kinase (MAPKKK, or MEKK), BCK1, is an essential component in this pathway for maintaining cell-wall integrity and preventing fungal cell lysis. We have identified a P. carinii MEKK gene and have expressed it in Saccharomyces cerevisiae to gain insights into its function. The P. carinii MEKK, PCBCK1, corrects the temperature-sensitive cell lysis defect of bck1Delta yeast. Further, at elevated temperature PCBCK1 restored the signaling defect in bck1Delta yeast to maintain expression of the temperature-inducible beta-1-3-glucan synthetase gene, FKS2. PCBCK1, as a functional kinase, is capable of autophosphorylation and substrate phosphorylation. Since glucan machinery is not present in mammals, a better understanding of this pathway in P. carinii might aid in the development of novel medications which interfere with the integrity of the Pneumocystis cell wall.
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Affiliation(s)
- Charles F Thomas
- Thoracic Diseases Research Unit, Division of Pulmonary, Critical Care and Internal Medicine, Department of Medicine, 826 Stabile Building, Mayo Clinic and Foundation, Rochester, MN 55905, USA.
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12
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Qureshi MH, Harmsen AG, Garvy BA. IL-10 modulates host responses and lung damage induced by Pneumocystis carinii infection. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:1002-9. [PMID: 12517967 DOI: 10.4049/jimmunol.170.2.1002] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Host responses to Pneumocystis carinii infection mediate impairment of pulmonary function and contribute to the pathogenesis of pneumonia. IL-10 is known to inhibit inflammation and reduce the severity of pathology caused by a number of infectious organisms. In the present studies, IL-10-deficient (IL-10 knockout (KO)) mice were infected with P. carinii to determine whether the severity of pathogenesis and the efficiency of clearance of the organisms could be altered in the absence of IL-10. The clearance kinetics of P. carinii from IL-10 KO mice was significantly enhanced compared with that of wild-type (WT) mice. This corresponded to a more intense CD4(+) and CD8(+) T cell response as well as an earlier neutrophil response in the lungs of IL-10 KO mice. Furthermore, IL-12, IL-18, and IFN-gamma were found in the bronchoalveolar lavage fluids at earlier time points in IL-10 KO mice suggesting that alveolar macrophages were activated earlier than in WT mice. However, when CD4(+) cells were depleted from P. carinii-infected IL-10 KO mice, the ability to enhance clearance was lost. Furthermore, CD4-depleted IL-10 KO mice had significantly more lung injury than CD4-depleted WT mice even though the intensity of the inflammatory responses was similar. This was characterized by increased vascular leakage, decreased oxygenation, and decreased arterial pH. These data indicate that IL-10 down-regulates the immune response to P. carinii in WT mice; however, in the absence of CD4(+) T cells, IL-10 plays a critical role in controlling lung damage independent of modulating the inflammatory response.
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MESH Headings
- Adjuvants, Immunologic/deficiency
- Adjuvants, Immunologic/genetics
- Adjuvants, Immunologic/physiology
- Animals
- CD4-Positive T-Lymphocytes/immunology
- CD4-Positive T-Lymphocytes/parasitology
- Carbon Dioxide/blood
- Cell Movement/genetics
- Cell Movement/immunology
- Chemokines/biosynthesis
- Chemokines/genetics
- Cytokines/biosynthesis
- Host-Parasite Interactions/genetics
- Host-Parasite Interactions/immunology
- Interleukin-10/deficiency
- Interleukin-10/genetics
- Interleukin-10/physiology
- Lung/immunology
- Lung/parasitology
- Lung/pathology
- Lymphocyte Depletion
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, SCID
- Oxygen/blood
- Pneumocystis/immunology
- Pneumocystis/pathogenicity
- Pneumonia, Pneumocystis/genetics
- Pneumonia, Pneumocystis/immunology
- Pneumonia, Pneumocystis/parasitology
- Pneumonia, Pneumocystis/physiopathology
- RNA, Messenger/biosynthesis
- Respiratory Function Tests
- Up-Regulation/genetics
- Up-Regulation/immunology
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Affiliation(s)
- Mahboob H Qureshi
- Department of Internal Medicine and Microbiology, University of Kentucky, Lexington 40536, USA
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13
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Yang YG. The role of interleukin-12 and interferon-gamma in GVHD and GVL. CYTOKINES, CELLULAR & MOLECULAR THERAPY 2000; 6:41-6. [PMID: 10976538 DOI: 10.1080/13684730050515903] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
The production of interleukin (IL)-12 by antigen-presenting cells after antigen stimulation is a critical step for initiating antigen-specific cellular immune responses, and interferon (IFN)-gamma produced by natural killer cells and activated T cells is a potent mediator of IL-12 effect. However, recent studies have demonstrated that administration of exogenous IL-12 paradoxically inhibits antigen-specific immunity of T cells in vivo, including allogeneic, autoimmune, and viral antigen-initiated T-cell responses. Interestingly, these inhibitory effects are also mediated by IFN-gamma, whose production is induced by IL-12. Thus, IL-12, a potent immunostimulatory cytokine, can paradoxically lead to immunosuppression. Notably, this cytokine has been shown to preserve graft-versus-leukemia (GVL) effects of allogeneic CD8+ T cells while inhibiting graft-versus-host disease (GVHD) in murine allogeneic bone marrow transplantation models. This article will review recent studies concerning the effect of IL-12 and IFN-gamma on the development of GVHD and the induction of GVL effects, and discuss the possible mechanisms responsible for IL-12-mediated separation of GVL effects from the GVHD-promoting activity of allogeneic T cells.
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Affiliation(s)
- Y G Yang
- Transplantation Biology Research Center, Surgical Service, Massachusetts General Hospital/Harvard Medical School, Boston 02129, USA.
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Yang YG, Sykes M. The role of interleukin-12 in preserving the graft-versus-leukemia effect of allogeneic CD8 T cells independently of GVHD. Leuk Lymphoma 1999; 33:409-20. [PMID: 10342569 DOI: 10.3109/10428199909058446] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Interleukin (IL)-12 is a potent immunostimulatory cytokine and inducer of Th1 cell activity and of cytotoxic T lymphocyte and natural killer cell function. This cytokine also has anti-tumor activity. Although IL-12 has been shown to be an important pathogenic cytokine in the induction of graft-versus-host disease (GVHD), injection of exogenous IL-12 to murine allogeneic bone marrow transplantation (BMT) recipients paradoxically leads to a significant delay in the onset of GVHD mortality in fully MHC plus multiple minor antigen-mismatched strain combinations, and to complete inhibition of GVHD in a single haplotype-mismatched murine BMT model. IL-12-induced inhibition of GVHD is associated with reduced donor T cell activation and expansion, in part through an interferon (IFN)-gamma-mediated mechanism. Fas-mediated apoptosis of donor T cells also plays a significant role in IL-12-induced GVHD protection. Importantly, IL-12 preserves the graft-versus-leukemia (GVL) effect of allogeneic CD8 T cells against EL4, a host-type leukemia/lymphoma, while inhibiting GVHD. Like the protective effect against GVHD, the GVL effect in IL-12-treated mice is dependent on IFN-gamma. Thus, treatment with IL-12 leads to separation of GVHD-promoting and GVL effects of allogeneic BMT via an IFN-gamma-dependent mechanism.
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Affiliation(s)
- Y G Yang
- Bone Marrow Transplantation Section, Transplantation Biology Research Center, Massachusetts General Hospital/Harvard Medical School, Boston 02129, USA
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15
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Pascale JM, Shaw MM, Durant PJ, Amador AA, Bartlett MS, Smith JW, Gregory RL, McLaughlin GL. Intranasal immunization confers protection against murine Pneumocystis carinii lung infection. Infect Immun 1999; 67:805-9. [PMID: 9916094 PMCID: PMC96390 DOI: 10.1128/iai.67.2.805-809.1999] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/1998] [Accepted: 11/19/1998] [Indexed: 11/20/2022] Open
Abstract
To evaluate the feasibility of mucosal immunization against Pneumocystis carinii (Pc) experimental infection, female BALB/c mice were intranasally immunized three times with soluble Pc antigens plus cholera toxin fraction B (Pc-CTB); control groups received either Pc antigen, CTB, or phosphate-buffered saline (PBS) alone. Two weeks after the last immunization, five animals from each group were sacrificed, and cellular and humoral immune responses were evaluated. The remaining five mice were CD4 depleted using a monoclonal antibody against mouse CD4 and inoculated with viable Pc. Significantly higher specific lymphoproliferative responses from tracheobronchial lymph node cells, immunoglobulin M (IgM) and IgG antibody levels in serum, and bronchoalveolar lavage (BAL)-derived IgA antibody concentrations were observed in the Pc-CTB group of mice relative to control groups (P < 0.01). Five weeks after challenge, no Pc organisms were observed in the lung smears of the Pc-CTB group, while the animals receiving antigen, adjuvant, or PBS had progressively higher numbers of Pc microorganisms. By Western blot analysis, a strongly reactive 55- to 60-kDa antigen was recognized by BAL IgA and by serum IgG. In summary, mucosal immunization elicited specific cellular and humoral immune responses and protected against Pc lung infection after immunosuppression.
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Affiliation(s)
- J M Pascale
- Department of Pathology and Laboratory Medicine, School of Medicine, Indiana University, Indianapolis, Indiana, USA
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16
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Yang YG, Dey BR, Sergio JJ, Pearson DA, Sykes M. Donor-derived interferon gamma is required for inhibition of acute graft-versus-host disease by interleukin 12. J Clin Invest 1998; 102:2126-35. [PMID: 9854048 PMCID: PMC509167 DOI: 10.1172/jci4992] [Citation(s) in RCA: 150] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
We have demonstrated that a single injection of interleukin (IL)-12 on the day of bone marrow transplantation (BMT) inhibits acute graft-versus-host disease (GVHD) in mice. This effect of IL-12 can be diminished by anti-interferon (IFN)-gamma mAb. To determine the mechanism by which IFN-gamma affects IL-12-mediated GVHD protection, we have compared the effect of IL-12 on GVHD in C57BL/6 wild-type (WT) or IFN-gamma gene knockout (GKO) recipients of fully major histocompatibility complex plus minor antigen-mismatched allogeneic BMT from WT or GKO BALB/c mice. Lethal acute GVHD was readily induced in the absence of IFN-gamma. IL-12 inhibited GVHD mortality to a similar extent in WT and GKO recipients of WT allogeneic BMT. However, neither WT nor GKO recipients were protected by IL-12 from GVHD induced by GKO allogeneic BMT. Moreover, the effective inhibition of host-reactive donor T cell activation and expansion that is associated with IL-12-mediated GVHD protection was dependent on the ability of BALB/c donors to produce IFN-gamma. These results demonstrate that (a) acute GVHD can be induced in the absence of IFN-gamma, (b) host IFN-gamma does not play a critical role in IL-12-induced GVHD protection, and (c) the protective effect of IL-12 against GVHD is dependent on the ability of the donor to produce IFN-gamma.
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Affiliation(s)
- Y G Yang
- Bone Marrow Transplantation Section, Transplantation Biology Research Center, Surgical Service, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts 02129, USA
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17
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Affiliation(s)
- J A Fishman
- Infectious Disease Unit, Massachusetts General Hosptial, Boston, Massachusetts 02114, USA.
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