Analysis and Characterization of Immune Cells and Their Activation Status by Whole-Cell MALDI-TOF Mass Spectrometry.

For 40 years, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been widely used in proteomics and biochemistry. It has been demonstrated in the last decade that MALDI-TOF MS can be used routinely to identify and classify numerous bacterial species or subspecies. We applied MALDI-TOF MS directly to intact mammalian cells, and we found that this method is valuable to identify human circulating cells and cells involved in the immune response including macrophages.

Imbalance of circulating monocyte subsets and PD-1 dysregulation in Q fever endocarditis: the role of IL-10 in PD-1 modulation.

Q fever endocarditis, a severe complication of Q fever, is associated with a defective immune response, the mechanisms of which are poorly understood. We hypothesized that Q fever immune deficiency is related to altered distribution and activation of circulating monocyte subsets. Monocyte subsets were analyzed by flow cytometry in peripheral blood mononuclear cells from patients with Q fever endocarditis and controls.

Intracellular bacteria interfere with dendritic cell functions: role of the type I interferon pathway.

Dendritic cells (DCs) orchestrate host defenses against microorganisms. In infectious diseases due to intracellular bacteria, the inefficiency of the immune system to eradicate microorganisms has been attributed to the hijacking of DC functions. In this study, we selected intracellular bacterial pathogens with distinct lifestyles and explored the responses of monocyte-derived DCs (moDCs).

Persistence of Coxiella burnetii, the agent of Q fever, in murine adipose tissue.

Coxiella burnetii, the agent of Q fever, is known to persist in humans and rodents but its cellular reservoir in hosts remains undetermined. We hypothesized that adipose tissue serves as a C. burnetii reservoir during bacterial latency.

Whole-cell MALDI-TOF mass spectrometry is an accurate and rapid method to analyze different modes of macrophage activation.

MALDI-TOF is an extensively used mass spectrometry technique in chemistry and biochemistry. It has been also applied in medicine to identify molecules and biomarkers. Recently, it has been used in microbiology for the routine identification of bacteria grown from clinical samples, without preparation or fractionation steps.

Early sex-specific modulation of the molecular clock in trauma.

Background: Immune system biology and most physiologic functions are tightly linked to circadian rhythms. Time of day-dependent variations in many biologic parameters also play a fundamental role in the disease process. We previously showed that the genes encoding the peripheral molecular clock were modulated in a sex-dependent manner in Q fever.

Whole-cell MALDI-TOF mass spectrometry: a tool for immune cell analysis and characterization.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is widely used in proteomics. It has been recently demonstrated that MALDI-TOF MS can be used to identify and classify numerous bacterial species or subspecies. We applied MALDI-TOF MS directly to intact mammalian cells, and we found that this method is valuable to identify human circulating cells and cells involved in the immune response including macrophages.

Monocyte responses in the context of Q fever: from a static polarized model to a kinetic model of activation.

Background: Q fever is caused by Coxiella burnetii, a bacterium that persists in M2-polarized macrophages. We wondered whether the concept of M1/M2 polarization is applicable to Q fever patients.

Methods: Monocytes from healthy controls were cultured with IFN-γ and IL-4, agonists of M1 and M2 macrophages, respectively, and their gene expression was assessed using whole-genome microarrays.

Impaired stimulation of p38α-MAPK/Vps41-HOPS by LPS from pathogenic Coxiella burnetii prevents trafficking to microbicidal phagolysosomes.

Variations in lipopolysaccharide (LPS), a bacterial outer membrane component, determine virulence of the obligate intracellular bacterium Coxiella burnetii, but the underlying mechanisms are unknown. We find that while avirulent C. burnetii LPS (avLPS) stimulates host p38α-MAPK signaling required for proper trafficking of bacteria containing compartments to lysosomes for destruction, pathogenic C.

Orientia tsutsugamushi, the causative agent of scrub typhus, induces an inflammatory program in human macrophages.

Scrub typhus is a life-threatening disease caused by Orientia tsutsugamushi, a bacterium that primarily infects endothelial cells both in vitro and in vivo. Evidence suggests that the interaction of O. tsutsugamushi with myeloid cells may play a pivotal role in O.

Overexpression of the Per2 gene in male patients with acute Q fever.

The prevalence of Q fever is higher in men than in women. Because the expression of circadian clock genes differs in male and female mice infected with Coxiella burnetii, we hypothesized that circadian genes are differently modulated in men and women with Q fever. The expression of the Per2 gene was significantly (P = .

Whole-cell MALDI-TOF MS: a new tool to assess the multifaceted activation of macrophages.

Whole-cell MALDI-TOF MS is routinely used to identify bacterial species in clinical samples. This technique has also proven to allow identification of intact mammalian cells, including macrophages. Here, we wondered whether this approach enabled the assessment human macrophages plasticity.

Role of innate and adaptive immunity in the control of Q fever.

Acute Q fever is commonly resolved without an antibiotic regimen, but a primary infection may develop into a chronic infection in a minority of cases. Coxiella burnetii, the causative agent of Q fever, is known to infect macrophages both in vitro and in vivo. It has been observed that the intracellular survival of C.

Defective monocyte dynamics in Q fever granuloma deficiency.

Background: The outcome of Q fever, an infectious disease caused by Coxiella burnetii, is associated with granuloma formation. Granulomas are present in patients with resolutive Q fever but are lacking in patients with chronic Q fever.

Methods: Study of granuloma formation requires invasive approaches.

The gene expression analysis of blood reveals S100A11 and AQP9 as potential biomarkers of infective endocarditis.

Background: The diagnostic and prognostic assessments of infective endocarditis (IE) are challenging. To investigate the host response during IE and to identify potential biomarkers, we determined the circulating gene expression profile using whole genome microarray analysis.

Methods And Results: A transcriptomic case-control study was performed on blood samples from patients with native valve IE (n = 39), excluded IE after an initial suspicion (n = 10) at patient's admission, and age-matched healthy controls (n = 10).

Foxp3(+)CD4(+)CD25(+) regulatory T cells are increased in patients with Coxiella burnetii endocarditis.

Chronic Q fever, which principally manifests as endocarditis, is characterized by Coxiella burnetii persistence and an impaired cell-mediated immune response. The long-term persistence of pathogens has been associated with the expansion of regulatory T cells (Tregs), the CD4(+) T-cell subset that is characterized by the expression of CD25 and Foxp3. We investigated the presence of Tregs in patients with acute Q fever (n = 17), known to exhibit an efficient immune response, patients with Q fever endocarditis (n = 54) and controls (n = 27) by flow cytometry.

Effects of Coxiella burnetii on MAPKinases phosphorylation.

Q fever is a disease caused by Coxiella burnetii, an obligate intracellular bacterium. Acute Q fever is characterized by efficient immune response, whereas chronic Q fever is characterized by dysregulated immune response as demonstrated by the lack of granulomas, the failure of C. burnetii to induce lymphoproliferation, and interferon-γ production.

The ligands of Numb proteins X1 and X2 are specific markers for chronic Q fever.

Q fever is a disease caused by Coxiella burnetii, an obligate intracellular bacterium. Acute Q fever is spontaneously resolutive and is characterized by an efficient immune response. In contrast, chronic Q fever is characterized by dysregulated immune response, as demonstrated by the failure of C.

Orientia tsutsugamushi stimulates an original gene expression program in monocytes: relationship with gene expression in patients with scrub typhus.

Orientia tsutsugamushi is the causal agent of scrub typhus, a public health problem in the Asia-Pacific region and a life-threatening disease. O. tsutsugamushi is an obligate intracellular bacterium that mainly infects endothelial cells.

Macrophage polarization and bacterial infections.

Purpose Of Review: Macrophages are the first line of defense against pathogens, and the mode of their activation will determine the success or failure of the host response to pathogen aggression. Based on limited numbers of markers, activated macrophages can be classified as classically activated (M1) macrophages that support microbicidal activity or alternatively activated (M2) macrophages that are not competent to eliminate pathogens. The development of high-throughput gene expression methods affords a reappraisal of the concept of macrophage activation in human infectious diseases.

Coxiella burnetii, the agent of Q fever, replicates within trophoblasts and induces a unique transcriptional response.

Q fever is a zoonosis caused by Coxiella burnetii, an obligate intracellular bacterium typically found in myeloid cells. The infection is a source of severe obstetrical complications in humans and cattle and can undergo chronic evolution in a minority of pregnant women. Because C.

Global analysis of circulating immune cells by matrix-assisted laser desorption ionization time-of-flight mass spectrometry.

Background: MALDI-TOF mass spectrometry is currently used in microbiological diagnosis to characterize bacterial populations. Our aim was to determine whether this technique could be applied to intact eukaryotic cells, and in particular, to cells involved in the immune response.

Methodology/principal Findings: A comparison of frozen monocytes, T lymphocytes and polymorphonuclear leukocytes revealed specific peak profiles.

IL-16 promotes T. whipplei replication by inhibiting phagosome conversion and modulating macrophage activation.

The replication of Tropheryma whipplei (the agent of Whipple's disease) within human macrophages is associated with the expression of IL-16, a cytokine known for its chemotactic and inflammatory properties. In this study, we asked whether IL-16 acts on T. whipplei replication by interfering with the endocytic pathway.

Sex-related differences in gene expression following Coxiella burnetii infection in mice: potential role of circadian rhythm.

Background: Q fever, a zoonosis due to Coxiella burnetii infection, exhibits sexual dimorphism; men are affected more frequently and severely than women for a given exposure. Here we explore whether the severity of C. burnetii infection in mice is related to differences in male and female gene expression profiles.

3D reconstruction of granulomas from transmitted light images implemented for long-time microscope applications.

Image analysis tools are essential to describe and quantify dynamic biological phenomena, such as early stages of granuloma formation. Granulomas are constituted of a collection of immune cells that contain pathogens, leading to their elimination. We presented here a new method to obtain granuloma 3D reconstruction from transmitted light images.