Project description:Characterization of chemokine and chemokine receptor expression during Pneumocystis infection in healthy and immunodeficient mice (part 3)
Project description:Characterization of chemokine and chemokine receptor expression during Pneumocystis infection in healthy and immunodeficient mice (part 4)
Project description:Characterization of chemokine and chemokine receptor expression during Pneumocystis infection in healthy and immunodeficient mice (part 1)
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:T cell response exert critical roles in the host adaptive immunity against Pneumocystis. However, the dynamics and diversity of T cell immune repertoire in HIV-negative Pneumocystis remains unknown. In this study, single-cell RNA and T cell receptor (TCR) sequencing were applied on cells sorted from lung tissues of mice infected with Pneumocystis from 0 to 4 weeks. Our data demonstrated clonally CD4+ T cells and CD8+ T cells expanded in response to Pneumocystis, which marked by highly expressed genes associated with T cell activation and cytotoxicity. The length distribution of CDR3 AA and gene usage variability were similar between Pneumocystis infected mice and control group. We tracked the transcriptome and TCR immune repertoires profiles of expanded lymphocyte clones during Pneumocystis infection, which demonstrate a reconstitution of the TCR immune repertoire after Pneumocystis 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
Project description:B cells play vital roles in host defense against Pneumocystis infection, however, the features of B cell receptor (BCR) repertoire in the disease progression remain unclear. Here we integrated single-cell RNA sequencing and single-cell BCR sequencing of immune cells from mice lung at uninfected state and 1-4 weeks postinfection, in order to illustrate the dynamic nature of B cell responses during Pneumocystis infection. We identified continuously increased plasma cells and an elevated ratio of (IgA+ IgG) to (IgD+ IgM) after infection. Moreover, Pneumocystis infection was associated with an increase of a naïve B subset characterized by elevated expression of the transcription factor ATF3. The proportion of clonal expanded cells progressively increased, with the BCR diversity decreased. Biased usage of V(D)J genes was observed, and the usage frequency of IGHV9-3 was elevated. Overall, these results present a detailed atlas of B cell transcriptional changes and BCR repertoire features in the context of Pneumocystis 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.