Histopathological and immunopathological studies on experimental pulmonary candidiasis]

Experimental pulmonary candidiasis was produced by intratracheal inoculation of candida albicans in mice. The pathological changes could be divided into two stages, dominated by polymorphonuclear leukocyte infiltration and granuloma formation respectively. Preincubation of C. albicans with mouse anti-C. albicans antibody showed no obvious effect on pathological changes of the lungs as compared with the changes in the control mice, indicating that specific antibody did not play a crucial role in the defence mechanism of the lungs against C. albicans infection in normal mice. In the mice injected with antineoplastic drugs and hormones, abundant pseudohyphae were found in the lungs. Tissue necrosis and hemorrhage were obvious.     

Infection with the roundworm Toxocara canis leads to exacerbation of experimental allergic airway inflammation

Background Epidemiological studies performed in developing as well as in western countries suggest that infection with Toxocara canis contributes to the development of atopic diseases. Objectives To investigate the association between infection with this helminth and allergy, we examined the effect of T. canis infection on experimental allergic airway inflammation. Methods BALB/c mice were infected by oral administration with 500 embryonated T. canis eggs followed by ovalbumin (OVA) sensitization and challenge to induce allergic airway inflammation. Results Infection with T. canis in combination with OVA treatment leads to exacerbation of pulmonary inflammation, eosinophilia, airway hyperresponsiveness, OVA specific and total IgE. Relative quantification of cytokine expression in the lungs of these mice showed increased expression of IL‐4 compared with mice that were only T. canis infected or OVA treated. Increased expression of IL‐5 and IL‐10 was measured in the lungs of T. canis‐infected or OVA‐treated mice compared with controls; however, combining infection and OVA treatment did not significantly change the expression of these cytokines. Conclusion A previous infection with T. canis leads to exacerbation of experimental allergic airway inflammation. These results have important consequences for findings on the helminths–allergy association. Several factors, including parasite species, infection of definitive vs. accidental host, parasite load and timing of infection, may influence whether an infection with helminths protects one from or enhances allergic manifestations.     

Induction of matrix metalloproteinase-9 in mice during Toxocara canis larvae migration

The relationships between inflammation in organs with Toxocara canis larval migration and matrix metalloproteinase-9 (MMP-9) were investigated following the infection of mice with 1,000 infective eggs. Gelatinase activity was defined by gelatin zymography, optimum pH, inhibitor specificity and Western blot analysis. MMP-9 activity was present in the lungs, liver, muscles, and brain during T. canis larval migration. This enzyme had a molecular weight of about 94 kDa and showed maximum activity in the pH range of 6–8. The increased MMP-9 proteinases coincided with larval recovery and the degree of inflammation among the four organs. These results suggest that MMP-9 may be associated with the inflammatory reaction to larval toxocariasis during early migration, and may therefore be a useful marker during T. canis larvae migration.     

Characterization of the Major Antigenic Protein 2 of Ehrlichia canis and Ehrlichia chaffeensis and Its Application for Serodiagnosis of Ehrlichiosis

Canine monocytic ehrlichiosis, caused by Ehrlichia canis or Ehrlichia chaffeensis, can result in clinical disease in naturally infected animals. Coinfections with these agents may be common in certain areas of endemicity. Currently, a species-specific method for serological diagnosis of monocytic ehrlichiosis is not available. Previously, we developed two indirect enzyme-linked immunosorbent assays (ELISAs) using the major antigenic protein 2 (MAP2) of E. chaffeensis and E. canis. In this study, we further characterized the conservation of MAP2 among various geographic isolates of each organism and determined if the recombinant MAP2 (rMAP2) of E. chaffeensis would cross-react with E. canis-infected dog sera. Genomic Southern blot analysis using digoxigenin-labeled species-specific probes suggested that map2 is a single-copy gene in both Ehrlichia species. Sequences of the single map2 genes of seven geographically different isolates of E. chaffeensis and five isolates of E. canis are highly conserved among the various isolates of each respective ehrlichial species. ELISA and Western blot analysis confirmed that the E. chaffeensis rMAP2 failed to serologically differentiate between E. canis and E. chaffeensis infections.     

Production of eosinophil chemotactic factor by CD8+ T-cells in Toxocara canis-infected mice

Production of eosinophil chemotactic factor by T-lymphocytes (ECF-L) was examined in Toxocara canis-infected mice. When spleen cells from T. canis-infected mice were cultured in serum-free RPMI1640, ECF-L production was detectable in an antigen-specific manner. The ECF-L production peaked at day 9 post-infection and then decreased. Depletion of Thy 1.2⁺ cells or CD8⁺ cells completely abrogated ECF-L production, whereas depletion of CD4⁺ cells did not, indicating that CD8⁺ T-cells are involved in the production of ECF-L. When bone marrow eosinophils obtained from T. canis-infected mice were preincubated with ECF-L, their chemotactic reactivity to parasite-derived ECFs was enhanced, whereas that of peritoneal cavity-derived eosinophils was not. Thus, ECF-L seems to be important not only as a chemoattractant but also as an activator of the chemotactic reactivity of naive eosinophils to the parasite-derived ECF in T. canis infection. Received: 4 June 1997 / Accepted: 11 July 1997     

Ultrasonically nebulized distilled water prevents exogenous histamine hyperreactivity in Toxocara canis-infected mice

Objective: This study examines the effect of ultrasonically nebulized distilled water inhalation on the systemic histamine hyperreactivity of Toxocara canis-infected mice.Methods: Uninfected and T. canis-infected mice received an intravenous sublethal dose of histamine and lethality rates were documented. At 24 days post infection, infected mice received ultrasonically nebulized distilled water inhalation for 1 h. Twenty-four hours later histamine levels were determined in bronchoalveolar lavage fluid as well as histamine lethality and toluidine blue-stained mast cell number in the lung.Results: T. canis-infected mice showed increased lethality after exposure to histamine in comparison to uninfected mice. Ultrasonically nebulized distilled water inhalation prevented histamine-induced lethality and reduced toluidine blue-stained mast cell numbers in the lung.Conclusions: The correlation between decreases in stained mast cells in the lung after ultrasonically nebulized distilled water inhalation and inhibition of histamine-induced lethality in these animals suggests participation of mast cells in the phenomenon and could be helpful in understanding the mechanisms of hyperreactivity during helminth parasite infections.Received 25 November 2004; returned for revision 14 January 2005; accepted by A. Falus 8 February 2005     

Effects of heterologous helminth infections on passive transfer of immunity using a mouse monoclonal IgE antibody againstSchistosoma japonicum

Passive transfer of immunity using a mouse monoclonal IgE antibody againstSchistosoma japonicum was found to be enhanced by heterologous helminth infections. BALB/c mice were infected withToxocara canis orNippostrongylus brasiliensis so as to induce eosinophilia prior to a challenge infection withS. japonicum. Recovery of adult schisotomes decreased in a group of mice that had been infected withT. canis and challenged with cercariae at the cutaneous site of sensitization with the IgE antibody as compared with that in mice that had been similarly treated with normal serum in the absence ofT. canis infection. Histological examinations revealed a close association of polymorphonuclear cells, including eosinophils, with damaged schistosomula in the skin ofT. canis-infected mice that had received the IgE antibody. An enhancement in worm reduction was also observed in mice harboring either of both nematodes when the monoclonal antibody had been injected intraperitoneally during the phase of migration of schistosomula from the skin to the lungs. In vitro studies on macrophage-mediated damage to schistosomula suggested that the enhancement in worm reduction was at least partly due to the activation of macrophages induced by the heterologous infections.     

Insertion of the CXC chemokine ligand 9 (CXCL9) into the mouse hepatitis virus genome results in protection from viral-induced encephalitis and hepatitis

The role of the CXC chemokine ligand 9 (CXCL9) in host defense following infection with mouse hepatitis virus (MHV) was determined. Inoculation of the central nervous system (CNS) of CXCL9−/− mice with MHV resulted in accelerated and increased mortality compared to wild type mice supporting an important role for CXCL9 in anti-viral defense. In addition, infection of RAG1−/− or CXCL9−/− mice with a recombinant MHV expressing CXCL9 (MHV-CXCL9) resulted in protection from disease that correlated with reduced viral titers within the brain and NK cell-mediated protection in the liver. Survival in MHV-CXCL9-infected CXCL9−/− mice was associated with reduced viral burden within the brain that coincided with increased T cell infiltration. Similarly, viral clearance from the livers of MHV-CXCL9-infected mice was accelerated but independent of increased T cell or NK cell infiltration. These observations indicate that CXCL9 promotes protection from coronavirus-induced neurological and liver disease.     

Acute respiratory distress syndrome induced by H9N2 virus in mice

H9N2 avian influenza viruses have repeatedly caused infections in swine and humans in some countries. The purpose of the present study was to evaluate the pulmonary pathology caused by H9N2 viral infection in mice. Six- to eight-week-old BALB/c mice were infected intranasally with 1 × 10⁴ MID₅₀ of A/Chicken/Hebei/4/2008(H9N2) virus. Clinical signs, pathological changes and viral replication in lungs, arterial blood gas, and cytokines in bronchoalveolar lavage fluid (BALF) were observed at different time points after infection. A control group was infected intranasally with noninfectious allantoic fluid. H9N2-infected mice exhibited severe respiratory syndrome, with a mortality rate of 60%. Gross observations showed that infected lungs were highly edematous. Major histopathological changes in infected lungs included diffuse pneumonia and alveolar damage, with neutrophil-dominant inflammatory cellular infiltration, interstitial and alveolar edema, hemorrhage, and severe bronchiolitis/peribronchiolitis. In addition, H9N2 viral infection resulted in severe progressive hypoxemia, lymphopenia, and a significant increase in neutrophils, tumor necrosis factor-α and interleukin-6 in BALF. The features described above satisfy the criteria for acute respiratory distress syndrome (ARDS). Our data show that H9N2 viral infection resulted in ARDS in mice, and this may facilitate studies of the pathogenesis of future potential H9N2 disease in humans.     

Monocyte-derived dendritic cells link localized secretory IgA deficiency to adaptive immune activation in COPD

Although activation of adaptive immunity is a common pathological feature of chronic obstructive pulmonary disease (COPD), particularly during later stages of the disease, the underlying mechanisms are poorly understood. In small airways of COPD patients, we found that localized disruption of the secretory immunoglobulin A (SIgA)-containing mucosal immunobarrier correlated with lymphocyte accumulation in airway walls and development of tertiary lymphoid structures (TLS) around small airways. In SIgA-deficient mice, we observed bacterial invasion into the airway epithelial barrier with lymphocytic infiltration and TLS formation, which correlated with the progression of COPD-like pathology with advanced age. Depletion of either CD4⁺ or CD8⁺ T lymphocytes reduced the severity of emphysema in SIgA-deficient mice, indicating that adaptive immune activation contributes to progressive lung destruction. Further studies revealed that lymphocyte infiltration into the lungs of SIgA-deficient mice was dependent on monocyte-derived dendritic cells (moDCs), which were recruited through a CCR2-dependent mechanism in response to airway bacteria. Consistent with these results, we found that moDCs were increased in lungs of COPD patients, along with CD4⁺ and CD8⁺ effector memory T cells. Together, these data indicate that endogenous bacteria in SIgA-deficient airways orchestrate a persistent and pathologic T lymphocyte response through monocyte recruitment and moDC differentiation.     

Arhgef1 Regulates α5β1 Integrin-Mediated Matrix Metalloproteinase Expression and Is Required for Homeostatic Lung Immunity

Pulmonary immunity depends on the ability of leukocytes to neutralize potentially harmful and frequent insults to the lung, and appropriate regulation of leukocyte migration and adhesion is integral to this process. Arhgef1 is a hematopoietic-restricted signaling molecule that regulates leukocyte migration and integrin-mediated adhesion. To explore a possible regulatory role for Arhgef1 in pulmonary immunity we examined the lung and its leukocytes in wild-type and Arhgef1-deficient animals. Here we report that the lungs of Arhgef1^−/− mice harbored significantly more leukocytes, increased expression and activity of matrix metalloproteinases (MMPs), airspace enlargement, and decreased lung elastance compared with wild-type lungs. Transfer of Arhgef1^−/− lung leukocytes to wild-type mice led to airspace enlargement and impaired lung function, indicating that loss of Arhgef1 in leukocytes was sufficient to induce pulmonary pathology. Furthermore, we showed that Arhgef1-deficient peritoneal macrophages when either injected into the lungs of wild-type mice or cultured on fibronectin significantly increased expression and activity of MMPs relative to control macrophages, and the in vitro fibronectin induction was dependent on the α5β1 integrin pair. Together these data demonstrate that Arhgef1 regulates α5β1-mediated MMP expression by macrophages and that loss of Arhgef1 by leukocytes leads to pulmonary pathology.Leukocytes are resident in the lungs of healthy individuals and are necessary for the innate and adaptive immune response toward potentially harmful foreign antigens that are exposed to the lung on a constant basis. Protection provided by innate lung immunity is controlled in part through the action of sentinel alveolar macrophages (AMs)¹ and alveolar epithelial cells.² Integrin-mediated signaling is a critical component of macrophage function and has been shown to be important for pulmonary immunity.^3,4 Furthermore, expression of extracellular matrix proteins are increased in several types of immune-related lung disease including chronic obstructive pulmonary disease (COPD).⁵Inappropriate regulation of pulmonary immune function has significant consequences and contributes to a number of lung diseases. In particular, it has been shown that the severity of COPD in humans correlates with the extent of inflammatory cell infiltrate comprising macrophages, neutrophils, CD4, CD8, and B lymphocytes.⁶ COPD has also been characterized by lung tissue damage, elevated production of matrix metalloproteinases (MMPs) by pulmonary leukocytes, and impaired lung function.^7–9 Precisely how, if at all, the increased leukocyte presence leads to lung pathology is not yet established.Leukocytes migrate in response to chemoattractants that signal via G-protein–coupled receptors to polarize the cell.¹⁰ Cell polarization is accomplished by the localized activation within the cell of Rho GTPase family members where Cdc42 and Rac are activated at the migrating cell leading edge and Rho at the trailing edge.¹⁰ Arhgef1 (Human Genome Organization nomenclature, formerly known as Lsc in mouse and p115RhoGEF in humans) is an intracellular protein restricted in expression to hematopoietic cells that regulates signaling from select G-protein–coupled receptors as well as RhoA activation.^11,12 Characterization of Arhgef1^−/− mice by our lab, and similar mouse mutants by others, have demonstrated a role for Arhgef1 in regulating leukocyte migration and adhesion.^13–16We have previously demonstrated that T lymphocytes depend on Arhgef1 to mount an adaptive secondary immune response to airway challenge.¹⁷ In the course of those studies, we found that naïve Arhgef1-deficient lungs reproducibly harbor an increased number of leukocytes compared with wild-type controls.¹⁷ To determine whether this increased presence of pulmonary leukocytes has functional consequences, we examined mutant pulmonary leukocytes and lung function in Arhgef1^−/− mice in the absence of experimental challenge. In this report, we show that loss of Arhgef1 expression by pulmonary leukocytes leads to airspace enlargement and decreased lung elastance and that elevated integrin-mediated expression of MMPs by mutant macrophages likely contributes to lung pathology.     

Degeneration of sensory afferent nerves enhances pulmonary inflammatory alterations in acute myocardial infarction in rats

BackgroundEvidence suggests proinflammatory changes in the lungs during acute myocardial infarction and a participation of neural mechanisms and substance P in the pathology. This study was undertaken to investigate the role and the mechanisms by which sensory afferent degeneration at neonatal stages exacerbates the pulmonary inflammatory responses to acute myocardial infarction in the adult rats.MethodsThe degeneration of capsaicin-sensitive afferent nerves was induced by administration of capsaicin to neonatal rats. The pulmonary inflammatory changes following coronary artery occlusion (CAO) were assessed by the analysis of the infiltration of neutrophils and tissue morphology in the lungs.ResultsSignificant increases in the pulmonary infiltration of neutrophils, up to 240% and 218% of the sham controls at 3 and 6 h, respectively, after CAO (P<.05) and marked pulmonary edema were observed. Degeneration of capsaicin-sensitive afferent nerves or antagonism of endogenous neurokinin (NK)-1 receptor exacerbated the pulmonary infiltration of neutrophils (up to 214% and 254% of the controls, respectively) and pulmonary tissue edema following the CAO.ConclusionThe findings indicate that degeneration of sensory afferent nerves enhances the pulmonary inflammatory changes in acute myocardial infarction, in which the endogenous NK may play a role.     

Vaccinated C57BL/6 Mice Develop Protective and Memory T Cell Responses to Coccidioides posadasii Infection in the Absence of Interleukin-10

High concentrations of lung tissue-associated interleukin-10 (IL-10), an anti-inflammatory and immunosuppressive cytokine, correlate with susceptibility of mice to Coccidioides spp. infection. In this study, we found that macrophages, dendritic cells, neutrophils, and both CD8⁺ and CD4⁺ T cells recruited to Coccidioides posadasii-infected lungs of nonvaccinated and vaccinated mice contributed to the production of IL-10. The major IL-10-producing leukocytes were CD8⁺ T cells, neutrophils, and macrophages in lungs of nonvaccinated mice, while both Foxp3⁺ and Foxp3⁻ subsets of IL-10⁺ CD4⁺ T cells were significantly elevated in vaccinated mice. Profiles of the recruited leukocytes in lungs revealed that only CD4⁺ T cells were significantly increased in IL-10^−/− knockout mice compared to their wild-type counterparts. Furthermore, ex vivo recall assays showed that CD4⁺ T cells isolated from vaccinated IL-10^−/− mice compared to vaccinated wild-type mice produced significantly higher amounts of IL-2, gamma interferon (IFN-γ), IL-4, IL-6, and IL-17A in the presence of a coccidioidal antigen, indicating that IL-10 suppresses Th1, Th2, and Th17 immunity to Coccidioides infection. Analysis of absolute numbers of CD44⁺ CD62L⁻ CD4⁺ T effector memory T cells (T_EM) and IFN-γ- and IL-17A-producing CD4⁺ T cells in the lungs of Coccidioides-infected mice correlated with better fungal clearance in nonvaccinated IL-10^−/− mice than in nonvaccinated wild-type mice. Our results suggest that IL-10 suppresses CD4⁺ T-cell immunity in nonvaccinated mice during Coccidioides infection but does not impede the development of a memory response nor exacerbate immunopathology of vaccinated mice over at least a 4-month period after the last immunization.     

Azilsartan attenuates lipopolysaccharide-induced acute lung injury via the Nrf2/HO-1 signaling pathway

Acute lung injury (ALI) is a severe complication of sepsis and hemorrhagic shock with high morbidity. In the present study, the protective effect of Azilsartan on lipopolysaccharide (LPS)-induced ALI in mice was investigated to explore the potential therapeutic property of Azilsartan for the treatment of ALI. LPS was used to induce an ALI model in mice. Hematoxylin–eosin (HE) staining sections were then evaluated for the pathological state of lung tissues. Bronchoalveolar lavage fluid (BALF) protein concentration, wet/dry weight ratios of lung tissues, and pulmonary myeloperoxidase (MPO) activity were detected to determine the degree of pulmonary injury. The number of total cells, macrophages, and neutrophils in BALF were counted using a hemocytometer to illustrate the inflammatory cell infiltration. The lung function was monitored using a spirometer. The concentrations of interleukin-1β (IL-1β), monocyte chemoattractant protein-1 (MCP-1), and interleukin-8 (IL-8) were determined using enzyme-linked immunosorbent assay (ELISA). Oxidative stress was evaluated by the superoxide dismutase (SOD) activity, glutathione (GSH), and malondialdehyde (MDA) concentrations in the lung tissue. The expressions of nuclear erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) were determined using Western blot analysis. Azilsartan therapy alleviated LPS-induced lung tissue damage, increased BALF protein concentration, lung wet to dry weight ratio, MPO activity, and macrophage and neutrophils infiltration. Also, Azilsartan ameliorated the production of inflammatory factors (IL-1β, MCP-1, and IL-8). Azilsartan ameliorated LPS-impaired lung SOD activity, the GSH concentration, and the MDA concentration. Mechanistically, Azilsartan activated the LPS-impaired Nrf2/HO-1 signaling pathway. Azilsartan therapy attenuates LPS-induced ALI via the Nrf2/HO-1 signaling pathway.

     

Up-regulation of tumor necrosis factor-alpha and interferon-gamma expression in the spleen and lungs of mice infected with the human Babesia isolate WA1

We analyzed cytokine expression in mice infected with the intraerythrocytic parasites Babesia microti and WA1. In C3H/HeN mice, WA1 infections were fatal, whereas B. microti infections were resolved. We propose that the proinflammatory cytokines tumor necrosis factor-alpha (TNFα) and interferon-gamma (IFNγ) contribute to the WA1-associated disease. WA1 infection was characterized by up-regulation of TNFα and IFNγ mRNA in the spleen. Previous studies in WA1-infected mice showed that pathologic lesions occurred primarily in the lungs, including pulmonary edema and intravascular margination of leukocytes. Analysis of cytokine expression in the lungs is important for an understanding of the disease process in WA1-infected mice. Expression of both TNFα and IFNγ mRNA was increased in the lungs of WA1-infected mice. Immunohistochemical staining confirmed the up-regulation of these proinflammatory cytokines in the lungs. Expression of TNFα and IFNγ was not up-regulated in the lungs of B. microti-infected mice. The results implicate TNFα and IFNγ in the pathogenesis of WA1-associated disease. Received: 30 June 1999 / Accepted: 27 August 1999     

Experimental disseminated aspergillosis in mice: Histopathological study

ObjectiveSystemic response to intravenous administration of Aspergillus fumigatus conidia was investigated in laboratory mice by survival/mortality, peripheral blood leukocyte response and histopathological evaluation of lung, liver, kidney and spleen.MethodsFemale C57Bl/6 mice were inoculated intravenously with 10⁶–5 × 10⁷ conidia of A. fumigatus (human isolate). Survival was monitored for two weeks. Histopathological analysis of organ was conducted postmortem and in survivors. Peripheral blood cells and leukocyte aggregation were determined in survivors.ResultsAdministration of all doses of A. fumigatus conidia caused mortality, but the highest mortality rate and the shortest time of survival were noted at the highest doses applied. Increased peripheral blood lymphocyte counts and their propensity to aggregate were observed in survivors. Histological analysis revealed : (1) pulmonary inflammatory response proportional to the applied dose of conidia with detectable fungi in lungs of animals that received the highest applied dose; (2) pronounced kidney inflammatory response with variable intensity of tubular dilation in survivors versus tubular destruction in nonsurvivors and proteinuria as well as hemoglobinuria at the highest doses applied; (3) presence of microabscesses in the liver; (4) white pulp hyperplasia and dose-dependent increase in lymphoid follicles in the spleen of infected animals that survived.ConclusionLymphocytosis and state of aggregation/adhesion in survivors and local histologically evident inflammatory response in all examined organs of mice characterize the response to systemic application of A. fumigatus conidia. The results obtained may contribute to our understanding of pathological mechanisms underlying disseminated aspergillosis and to the evaluation of therapeutic interventions that might improve survival or lessen pathology.     

Interleukin-4 Enhances Pulmonary Clearance of Pseudomonas aeruginosa

To determine the effects of interleukin-4 (IL-4) on bacterial clearance from the mouse lung, transgenic mice expressing IL-4 in respiratory epithelial cells under the control of the Clara cell secretory protein promoter (CCSP-IL-4 mice) were infected intratracheally with Pseudomonas aeruginosa. Survival of CCSP-IL-4 mice following bacterial administration was markedly improved compared with that of control mice. While bacteria proliferated in lungs of wild-type mice, a rapid reduction in the number of bacteria was observed in the IL-4 mice as early as 6 h postinfection. Similarly, intranasal administration of IL-4 enhanced bacterial clearance from the lungs of wild-type mice. While acute and chronic IL-4 increased the numbers of neutrophils in bronchoalveolar lavage fluid, bacterial infection was associated with acute neutrophilic pulmonary infiltration, and this response was similar in the presence or absence of IL-4. Local administration or expression of IL-4 in the mouse lung enhanced pulmonary clearance of P. aeruginosa in vivo and decreased mortality following infection.     

OASL1-Mediated Inhibition of Type I IFN Reduces Influenza A Infection-Induced Airway Inflammation by Regulating ILC2s

PurposeThree observations drove this study. First, 2′-5′-oligoadenylate synthetase-like protein (OASL) is a negative regulator of type I interferon (IFN). Second, type I IFN plays a central role during virus infections and the pathogenesis of various diseases, including asthma. Third, influenza A virus (IAV) causes non-eosinophilic asthma. To evaluate the potential relationships between OASL, type I IFN, and pulmonary innate immune cells in IAV-induced acute airway inflammation by using Oasl1^-/- mice.MethodsAsthma was induced in wild-type (WT) and Oasl1^-/- mice with IAV or ovalbumin (OVA). Airway hyperreactivity (AHR) and immune cell infiltration in the bronchoalveolar lavage (BAL) fluids were measured. The immune cells in the lungs were analyzed by flow cytometry. To investigate the ability of type I IFN to shape the response of lung type 2 innate lymphoid cells (ILC2s), IFN-α was treated intratracheally. Plasmacytoid dendritic cells (pDCs) sorted from bone marrow and ILC2s sorted from lungs of naive mice were co-cultured with/without interferon-alpha receptor subunit 1 (IFNAR-1)-blocking antibodies.ResultsIn the IAV-induced asthma model, Oasl1^-/- mice developed greater AHR and immune cell infiltration in the BAL fluids than WT mice. This was not observed in OVA-induced asthma, a standard model of allergen-induced asthma. The lungs of infected Oasl1^-/- mice also had elevated DC numbers and Ifna expression and depressed IAV-induced ILC2 responses, namely, proliferation and type 2 cytokine and amphiregulin production. Intratracheal administration of type I IFN in naïve mice suppressed lung ILC2 production of type 2 cytokines and amphiregulin. Co-culture of ILC2s with pDCs showed that pDCs inhibit the function of ILC2s by secreting type I IFN.ConclusionsOASL1 may impede the IAV-induced acute airway inflammation that drives AHR by inhibiting IAV-induced type I IFN production from lung DCs, thereby preserving the functions of lung ILC2s, including their amphiregulin production.     

H3N2猪流感病毒诱导的小鼠急性肺损伤与SOD、NO、MDA和OH·变化的相关性

目的: 探讨超氧化物歧化酶(SOD)活性以及一氧化氮(NO)、丙二醛(MDA)和羟自由基(OH·)含量的变化与H3N2猪流感病毒诱导的小鼠肺损伤的关系。方法: 选用6-8周龄、SPF级BALB/c小鼠80只,随机分为H3N2病毒感染急性肺损伤组和模拟感染对照组,每组各40只。在感染后的第3、5、7、10和14 d,每组处死小鼠6只,做如下处理:其中2只小鼠取肺组织进行HE染色,观察肺组织的病理学变化;剩余4只小鼠处死,收集血液分离血清;然后进行支气管肺泡灌洗,收集支气管肺泡灌洗液(BALF)。测BALF 和血清内SOD活性以及NO、MDA和OH·含量。结果: 病毒感染小鼠肺脏 组织学变化表现为以严重的肺泡间质水肿、炎性细胞渗出、出血为特征的弥漫性肺泡损伤;与模拟感染对照组相比,感染组BALF与血清内的NO、MDA和OH·的含量均明显增加,差异显著;感染组SOD活性与对照组相比显著下降。BALF内SOD、NO、MDA和OH·的变化幅度明显大于血清的变化。结论: 感染小鼠血清和BALF内NO、MDA和OH·显著升高,表明在H3N2猪流感病毒诱导的小鼠肺损伤过程中上述自由基可能发挥重要作用。     

Salmonella typhimurium exacerbates injuries but resolves fibrosis in liver and spleen during Schistosoma mansoni infection

BackgroundIn most developing or undeveloped countries, patients are often co-infected with multiple pathogens rather than a single pathogen. While different pathogens have their impact on morbidity and mortality, co-infection of more than one pathogen usually made the disease outcome different. Many studies reported the co-infection of Schistosoma with Salmonella in pandemic areas. However, the link or the underlying mechanism in the pathogenesis caused by Schistosoma-Salmonella co-infection is still unknown.MethodsIn this study, Salmonella typhimurium (S. typhimurium) was challenged to Schistosoma mansoni (S. mansoni)-infected mice. Further experiments such as bacterial culture, histopathological examination, western blotting, and flow cytometry were performed to evaluate the outcomes of the infection. Cytokine responses of the mice were also determined by ELISA and real-time quantitative PCR.ResultsOur results demonstrated that co-infected mice resulted in higher bacterial excretion in the acute phase but higher bacterial colonization in the chronic phase. Lesser egg burden was also observed during chronic schistosomiasis. Infection with S. typhimurium during schistosomiasis induces activation of the inflammasome and apoptosis, thereby leading to more drastic tissue damage. Interestingly, co-infected mice showed a lower fibrotic response in the liver and spleen. Further, co-infection alters the immunological functioning of the mice, possibly the reason for the observed pathological outcomes.ConclusionCollectively, our findings here demonstrated that S. mansoni-infected mice challenged with S. typhimurium altered their immunological responses, thereby leading to different pathological outcomes.