Project description:Type I IFN-signaling suppresses an excessive IFN-{gamma} response and prevents lung damage and chronic inflammation following Pneumocystis (PC)-infection and clearance in CD4 T cell-competent mice. Type I IFN -signaling in pulmonary CD11c+ DCs and alveolar macrophages may prevent chronic inflammation following PC lung infection and clearance by suppressing an excessive IFN-g-response via the induction of SOCS1.
Project description:Type I IFN-signaling suppresses an excessive IFN-{gamma} response and prevents lung damage and chronic inflammation following Pneumocystis (PC)-infection and clearance in CD4 T cell-competent mice. Type I IFN -signaling in pulmonary CD11c+ DCs and alveolar macrophages may prevent chronic inflammation following PC lung infection and clearance by suppressing an excessive IFN-g-response via the induction of SOCS1. IFNAR-/- and wildtype mice were both Pneumocystis infected via itratracheal instillation. Pulmonary CD11c+ cells were isolated from collagen digested lungs at day 7 and day 14 post infection from both wildtype and IFNAR-/- mice using a magnetic cell sorting technique from Miltenyi with CD11c microbeads. Cells from three individual animals per group were isolated and assessed. Comparison of 2 treatment types at 2 timepoints to determine whether type I IFN signaling is initiated in resident and early recruited pulmonary CD11c+ cells following Pneumocystis lung infection and whether this is relevant to the outcome of the inflammatory response during the initiation of clearance.
Project description:In wild-type mice, expression of chemokines that are ligands for Ccr2, Cxcr3, and Cxcr2 increased at days 32 to 41 post-infection, with a return to baseline by day 75. Concomitant increases were seen in Ccr2 and Cxcr3 but not in Cxcr2 expression. Induction of these same factors also occurred in CD40-ligand and CD40 knockout mice but only at a much later time-point, during uncontrolled Pneumocystis pneumonia (PCP). Expression of CD4 Th1 markers was increased in wild-type mice during clearance of infection. Ccr2 and Cx3cr1 knockout mice cleared Pneumocystis infection with kinetics similar to wild-type mice, and all animals developed anti-Pneumocystis antibodies. Upregulation of Ccr2 and Cxcr3 and their ligands supports an important role for T helper cells and mononuclear phagocytes in the clearance of Pneumocystis infection. However, based on the current and prior studies, no single chemokine receptor appears to be critical to the clearance of Pneumocystis.
Project description:In wild-type mice, expression of chemokines that are ligands for Ccr2, Cxcr3, and Cxcr2 increased at days 32 to 41 post-infection, with a return to baseline by day 75. Concomitant increases were seen in Ccr2 and Cxcr3 but not in Cxcr2 expression. Induction of these same factors also occurred in CD40-ligand and CD40 knockout mice but only at a much later time-point, during uncontrolled Pneumocystis pneumonia (PCP). Expression of CD4 Th1 markers was increased in wild-type mice during clearance of infection. Ccr2 and Cx3cr1 knockout mice cleared Pneumocystis infection with kinetics similar to wild-type mice, and all animals developed anti-Pneumocystis antibodies. Upregulation of Ccr2 and Cxcr3 and their ligands supports an important role for T helper cells and mononuclear phagocytes in the clearance of Pneumocystis infection. However, based on the current and prior studies, no single chemokine receptor appears to be critical to the clearance of Pneumocystis.
Project description:Pulmonary hypertension (PH) is a disease of diverse etiology. While primary PH can develop in the absence of prior disease, PH more commonly develops in conjunction with other pulmonary pathologies. We previously reported a mouse model in which PH occurs as a sequelae of Pneumocystis infection in the context of transient CD4 depletion. Here, we demonstrate that instead of the expected Th2 pathways, the Th1 cytokine IFN-M-NM-3 was essential for the development of PH, as wild type mice developed PH, but not IFN-M-NM-3 knockout mice. Because gene expression analysis showed few strain differences that were not immune function related, we focused on those responses as potential pathologic mechanisms. While there were several differences in cellular and cytokine response that warrant further examination, we focused on three important aspects. First, if CD4 cells were continuously depleted, but the infection was limited by antibiotic treatment, then PH did not occur, confirming that CD4 T-cells are required for PH development. Second, although CD8 T-cells are implicated in the pathology of unabated Pneumocystis pneumonia, they did not have a role in the onset of PH. Finally, although there are differences in the amounts of the pulmonary immune cells, differences existed in phenotypes of immune cells that correlated with PH, such as elevated CD204 expression in lung CD11c+ cells. Two groups of BALB/c mice (3 per group) were infected i.t. with 10e7 Pneumocystis; one of those groups also received 4 injections of CD4 T-cell depleting antibodies beginning 3 days prior to infection and ending 7 days after infection. A third group was IFN-gamma knockout mice infected with Pneumocystis and depleted of CD4 cells in the same way. A fourth group of control non-treated BALB/c mice were also used. AT 38 days post infection, lung tissues were taken, and RNA was extracted to allow for differential gene expression analysis
Project description:Pneumocystis is a pathogen of immunocompromised hosts but can also infect healthy hosts, in whom infection is rapidly controlled and cleared. To better understand the immune mechanisms contributing to clearance of infection, microarray methods were used to examine differential gene expression in the lungs of C57BL/6 and CD40 ligand knock-out (CD40L-KO) mice over time following exposure to Pneumocystis. Immuncompetent C57BL/6 mice, which control and clear infection efficiently, showed a robust response to infection characterized by the upregulation of 349 primarily immune-response associated genes. Temporal changes in the expression of these genes suggested that there was an early (week 2) primarily innate response, that waned without controlling infection; this were followed by primarily adaptive immune responses that peaked at week 5 and successfully cleared the infection. In conjunction with the latter, there was an increased expression of B cell associated (immunoglobulin) genes at week 6 that persisted through 11 weeks. In contrast, CD40L-KO mice, which are highly susceptible to developing severe Pneumocystis pneumonia, showed essentially no upregulation of immune-response associated genes at days 35 to 75. Immunohistochemical staining supported these observations by demonstrating an increase in CD4+, CD68+, and CD19+ cells in C57BL/6 but not CD40L-KO mice. Thus, the healthy host demonstrates a robust biphasic response to infection by Pneumocystis; CD40 ligand is an essential upstream regulator of the adaptive immune responses that efficiently control infection and prevent development of progressive pneumonia. Keywords: Time course response Pneumocystis murina infection wild type versus CD40L-KO mice
Project description:Inhibition of IFN-I signaling promotes the control of persistent virus infection, but the underlying mechanisms remain poorly understood. Here we report that genetic ablation of IFNAR1 specifically in NK cells led to elevated numbers of T follicular helper cells, germinal center B cells, and plasma cells, resulting in hastened virus clearance comparable to IFNAR1 blockade by an IFNAR1 neutralizing antibody. Antigen-specific B cells and antiviral antibodies were essential for the accelerated control of LCMV Cl13 infection following IFNAR1 blockade. IFNAR1 signaling in NK cells promoted NK cell maturation, function, and killing of antigenspecific CD4 and CD8 T cells. Therefore, Inhibition of IFN I signaling in NK cells enhances CD4 and CD8 T cell responses, elevates humoral immune response, and thereby facilitates the control of persistent virus infection.
Project description:Pneumocystis is a pathogen of immunocompromised hosts but can also infect healthy hosts, in whom infection is rapidly controlled and cleared. To better understand the immune mechanisms contributing to clearance of infection, microarray methods were used to examine differential gene expression in the lungs of C57BL/6 and CD40 ligand knock-out (CD40L-KO) mice over time following exposure to Pneumocystis. Immuncompetent C57BL/6 mice, which control and clear infection efficiently, showed a robust response to infection characterized by the upregulation of 349 primarily immune-response associated genes. Temporal changes in the expression of these genes suggested that there was an early (week 2) primarily innate response, that waned without controlling infection; this were followed by primarily adaptive immune responses that peaked at week 5 and successfully cleared the infection. In conjunction with the latter, there was an increased expression of B cell associated (immunoglobulin) genes at week 6 that persisted through 11 weeks. In contrast, CD40L-KO mice, which are highly susceptible to developing severe Pneumocystis pneumonia, showed essentially no upregulation of immune-response associated genes at days 35 to 75. Immunohistochemical staining supported these observations by demonstrating an increase in CD4+, CD68+, and CD19+ cells in C57BL/6 but not CD40L-KO mice. Thus, the healthy host demonstrates a robust biphasic response to infection by Pneumocystis; CD40 ligand is an essential upstream regulator of the adaptive immune responses that efficiently control infection and prevent development of progressive pneumonia. Keywords: Time course response Pneumocystis murina infection wild type versus CD40L-KO mice In experiment 1, C57BL/6 and CD40L-KO mice were co-housed in 2 cages; one cage was exposed to a P. murina-infected seeder, while the second was unexposed. Mice (3 per group) were sacrificed at day 32. Because the initial study demonstrated very little change in gene expression in CD40L-KO mice, only C57BL/6 mice were used for experiments 2 and 3. In Experiment 2, three cages (10 animals/cage) were set up: 2 cages were exposed to P. murina, and one was unexposed. Animals (5 per cage) were sacrificed at days 34 and 41. In Experiment 3, which focused on gene expression early after exposure to P. murina, five cages (9-10 animals/cage) were set up, of which 3 were exposed and 2 were unexposed. Animals (1-3 per cage) were sacrificed at days 7, 14 and 21 of exposure. Experiment 4 was designed to verify the initial results in CD40L-KO mice, and included 5 unexposed controls and 4 mice exposed for 35 days.
Project description:With the extensive use of glucocorticoids (GCs), the occurrence of immunocompromised patients is increasingly raised. Pneumonia, caused by opportunistic pathogens including Pneumocystis (PC), is a major cause of morbidity and mortality. The loss of adaptive immune responses have been demonstrated as a key reason for the infection of Pneumocystis. Nevertheless, the alterations of innate immunity by GCs treatment and the subsequent effects remain unclear. Here we integrated the single-cell RNA sequencing and metabolomic analysis to decipher the alterations of the innate immunity in immunocompromised mice with PC infection. Our results have shown that a group of Mmp12+ macrophages was enriched in lung tissues of the immunocompetent mice upon PC infection. Pathway enrichment analysis showed obviously up-regulated pro-inflammatory pathways, suggesting that these Mmp12+ macrophages may be essential for the protection against PC infection. In the dexamethasone (DEX)-treated mice, the monocyte differentiation towards Mmp12+ macrophages was dramatically hampered via downregulating the granulocyte/macrophage colony-stimulating factor (GM-CSF) signaling. Further, DEX treatment simultaneously impaired the metabolic and functional integrity of resident macrophages through down-regulating lysophosphatidylcholine and GM-CSF. These induced suppressed host antimicrobial capacities. The results of our study provides a rich resource for understanding the heterogeneity and changes in macrophages and also provides novel insights into immune response take place in GCs-induced immunosuppressed mice during PC infection.
Project description:Pulmonary hypertension (PH) is a disease of diverse etiology. While primary PH can develop in the absence of prior disease, PH more commonly develops in conjunction with other pulmonary pathologies. We previously reported a mouse model in which PH occurs as a sequelae of Pneumocystis infection in the context of transient CD4 depletion. Here, we demonstrate that instead of the expected Th2 pathways, the Th1 cytokine IFN-γ was essential for the development of PH, as wild type mice developed PH, but not IFN-γ knockout mice. Because gene expression analysis showed few strain differences that were not immune function related, we focused on those responses as potential pathologic mechanisms. While there were several differences in cellular and cytokine response that warrant further examination, we focused on three important aspects. First, if CD4 cells were continuously depleted, but the infection was limited by antibiotic treatment, then PH did not occur, confirming that CD4 T-cells are required for PH development. Second, although CD8 T-cells are implicated in the pathology of unabated Pneumocystis pneumonia, they did not have a role in the onset of PH. Finally, although there are differences in the amounts of the pulmonary immune cells, differences existed in phenotypes of immune cells that correlated with PH, such as elevated CD204 expression in lung CD11c+ cells.