Project description:Peripheral blood was collected from human patients infected with influenza A virus only or in addition with bacterial pathogens and at different days after hospital admission. For comparison, blood from healthy controls was collected. Gene expression differences were detected in influenza and bacterial infections compared to healthy controls, and at various days post infection.
Project description:Opportunistic oral infections are ultimately presented in a vast majority of HIV-infected patients, often causing debilitating lesions that also contribute to deterioration in nutritional health. Although appreciation for the role that the microbiota is likely to play in the initiation and/or enhancement of oral infections has grown considerably in recent years, little is known about the impact of HIV infection on host-microbe interactions within the oral cavity. In the current study, we characterize modulations in the bacterial composition of the lingual microbiome in patients with treated and untreated HIV infection. Bacterial species profiles were elucidated by microarray assay and compared between untreated HIV infected patients, HIV infected patients receiving antiretroviral therapy, and healthy HIV negative controls. The relationship between clinical parameters (viral burden and CD4+ T cell depletion) and the loss or gain of bacterial species was evaluated in each HIV patient group. Characterization of modulations in the dorsal tongue (lingual) microbiota that are associated with chronic HIV infection.
Project description:Severe bacterial (pneumococcal) infections are commonly associated with influenza and are significant contributors to the excess morbidity and mortality of influenza. Disruption of lung tissue integrity during influenza participates in bacterial pulmonary colonization and dissemination out of the lungs. Interleukin (IL)-22 has gained considerable interest in anti-inflammatory and anti-infection immunotherapy over the last decade. In the current study, we investigated the effect of exogenous IL-22 delivery on the outcome of bacterial superinfection post-influenza. Our data show that exogenous treatment of influenza-infected mice with recombinant IL-22 reduces bacterial dissemination out of the lungs but is without effect on pulmonary bacterial burden. We describe an IL-22 specific gene signature in the lung tissue of IAV-infected (and naïve) mice that might explain the observed effects. Indeed, exogenous IL-22 modulates gene expression profile in a way suggesting a reinforcement of tissue integrity. Our results open the way to alternative approaches for limiting post-influenza bacterial superinfection, particularly systemic bacterial invasion.
Project description:Influenza associated bacterial super-infections have devastating impacts on the lung and can result in increased risk of mortality. New strains of influenza circulate throughout the population yearly promoting the establishment of immune memory. Nearly all individuals have some degree of influenza memory prior to adulthood. Due to this we sought to understand the role of immune memory during bacterial super-infections. An influenza heterotypic immunity model was established using influenza A/PR/8/34 and A/X31. We report here that influenza experienced mice are more resistant to secondary bacterial infection with methicillin-resistant Staphylococcus aureus as determined by wasting, bacterial burden, pulmonary inflammation, and lung leak, despite significant ongoing lung remodeling. Multidimensional flow cytometry and lung transcriptomics revealed significant alterations in the lung environment in influenza-experienced mice compared with naïve animals. These include changes in the lung monocyte and T cell compartments, characterized by increased expansion of influenza tetramer specific CD8+ T cells. The protection that was seen in memory experienced mouse model is associated with the reduction in inflammatory mechanisms making the lung less susceptible to damage and subsequent bacterial colonization. These findings provide insight into how influenza heterotypic immunity re-shapes the lung environment and the immune response to a re-challenge event, which is highly relevant to the context of human infection.
Project description:Opportunistic oral infections are ultimately presented in a vast majority of HIV-infected patients, often causing debilitating lesions that also contribute to deterioration in nutritional health. Although appreciation for the role that the microbiota is likely to play in the initiation and/or enhancement of oral infections has grown considerably in recent years, little is known about the impact of HIV infection on host-microbe interactions within the oral cavity. In the current study, we characterize modulations in the bacterial composition of the lingual microbiome in patients with treated and untreated HIV infection. Bacterial species profiles were elucidated by microarray assay and compared between untreated HIV infected patients, HIV infected patients receiving antiretroviral therapy, and healthy HIV negative controls. The relationship between clinical parameters (viral burden and CD4+ T cell depletion) and the loss or gain of bacterial species was evaluated in each HIV patient group.
Project description:Radiation therapy is a mainstay of cancer treatment, with more than 50% of all cancer patients receiving radiation during the course of their disease. Tumor irradiation can activate both innate and adaptive immune responses, and these responses can be pro- or anti-tumor growth . These observations have led to the search for antitumor approaches combining radiotherapy and specific immunotherapies, most commonly strategies promoting the systemic activation of T cells. Thus far, however, many cancer patients still suffer from local recurrence and/or untreatable metastatic disease after radiotherapy. Here we combine radiotherapy with activation of macrophage-mediated phagocytosis via blockade of the ?don?t-eat-me? cell surface molecule CD47 in small-cell lung cancer (SCLC), a highly metastatic form of lung cancer for which treatment options remain limited. We found that irradiation of SCLC cells in culture results in the secretion of inflammatory cytokines that results in increased migration and phagocytosis by macrophages. In vivo, CD47 blockade potently enhances the local antitumor effects of radiation therapy in murine and human pre-clinical models of SCLC. Strikingly, CD47 blockade also stimulates abscopal antitumor effects inhibiting the growth of non-irradiated SCLC tumors in mice receiving radiation. Similar abscopal antitumor effects were observed in colon cancer and lymphoma models. Surprisingly, these abscopal effects are completely independent of T cells but require macrophages that migrate into the non-irradiated tumor sites in response to inflammatory signals mediated by radiation and are locally activated by CD47 blockade to eliminate cancer cells. The systemic activation of antitumor macrophages following radiotherapy and CD47 blockade may be particularly important in cancer patients who suffer from metastatic disease.
Project description:Introduction: Diagnosis of severe influenza pneumonia remains challenging because of the lack of correlation between presence of influenza virus and patient’s clinical status. We conducted gene expression profiling in the whole blood of critically ill patients to identify a gene signature that would allow clinicians to distinguish influenza infection from other causes of severe respiratory failure (e.g. bacterial pneumonia, non-infective systemic inflammatory response syndrome). Methods: Whole blood samples were collected from critically ill individuals and assayed on Illumina HT-12 gene expression beadarrays. Differentially expressed genes were determined by linear mixed model analysis and over-represented biological pathways determined using GeneGo MetaCore. Results: The gene expression profile of H1N1 influenza A pneumonia was distinctly different from bacterial pneumonia and systemic inflammatory response syndrome. The influenza gene expression profile is characterized by up-regulation of genes from cell cycle regulation, apoptosis and DNA-damage response pathways. In contrast, no distinctive gene-expression signature was found in patients with bacterial pneumonia or systemic inflammatory response syndrome. The gene expression profile of influenza infection persisted through five days of follow-up. Furthermore, in patients with primary H1N1 influenza A infection who subsequently developed bacterial co-infection, the influenza gene-expression signature remained unaltered, despite the presence of a super-imposed bacterial infection. Conclusions: The whole blood expression profiling data indicates that the host response to influenza pneumonia is distinctly different from that caused by bacterial pathogens. This information may speed up identification of the cause of infection in patients presenting with severe respiratory failure, allowing appropriate patient care to be undertaken more rapidly. Daily PAXgene samples for up to 5 days for; influenza A pneumonia patients (n=8), bacterial pneumonia patients (n=16), mixed bacterial and influenza A pneumonia patients (n=3), systemic inflammatory response patients (SIRS, n=13). Days 1 and 5 PAXgene samples for healthy control individuals