scholarly journals Borrelia burgdorferi Organisms Lacking Plasmids 25 and 28-1 Are Internalized by Human Blood Phagocytes at a Rate Identical to That of the Wild-Type Strain

2005 ◽  
Vol 73 (9) ◽  
pp. 5547-5553 ◽  
Author(s):  
Samiya Al-Robaiy ◽  
Jens Knauer ◽  
Reinhard K. Straubinger
Keyword(s):  
Borrelia Burgdorferi ◽  
Human Blood ◽  
Fluorescein Isothiocyanate ◽  
Blood Monocytes ◽  
Wild Type ◽  
Phagocytic Cells ◽  
Linear Plasmids ◽  
High Passage ◽  
The Impact

ABSTRACT Lyme borreliosis caused by Borrelia burgdorferi is a persistent infection capable of withstanding the host's vigorous immune response. Several reports have shown that the spirochete's linear plasmids 25 and 28-1 are essential for its infectivity. In this context, it was proposed that Borrelia burgdorferi organisms control their uptake by macrophages and polymorphonuclear leukocytes (PMNs) through plasmid-encoded proteins and that this mechanism confers resistance to phagocytosis. To investigate this proposal, a precise flow-cytometry-based method with human blood was used to study the impact of the plasmids 25 and 28-1 on B. burgdorferi clearance over 150 min and to investigate whether low-passage organisms are more resistant to phagocytosis than high-passage B. burgdorferi. Exposure of human blood PMNs or blood monocytes to fluorescein isothiocyanate-labeled B. burgdorferi B31 organisms lacking the linear plasmids 25, 28-1, or both revealed that all spirochete populations were internalized at the same rate as the wild-type borrelia parent strain B31. Moreover, no differences in phagocytosis kinetics were detected when low- or high-passage wild-type B. burgdorferi B31 or N40 were cocultured with blood cells. Plasmid loss and probable associated surface protein changes due to serial in vitro propagation of B. burgdorferi do not affect the resistance of these organisms to internalization by phagocytic cells. In particular, we found no evidence for a plasmid-controlled (lp25 and lp28-1) resistance of B. burgdorferi to phagocytosis by leukocytes of the host's innate immune system.

scholarly journals Production of Noncapped Genomic RNAs Is Critical to Sindbis Virus Disease and Pathogenicity

mBio ◽  
2020 ◽  
Vol 11 (6) ◽  
Author(s):  
Autumn T. LaPointe ◽  
V Douglas Landers ◽  
Claire E. Westcott ◽  
Kevin J. Sokoloski
Keyword(s):  
Sindbis Virus ◽  
Virus Disease ◽  
Severe Disease ◽  
Wild Type Virus ◽  
Wild Type ◽  
Genomic Rnas ◽  
Mortality And Morbidity ◽  
The Impact

ABSTRACT Alphaviruses are positive-sense RNA viruses that utilize a 5′ cap structure to facilitate translation of viral proteins and to protect the viral RNA genome. Nonetheless, significant quantities of viral genomic RNAs that lack a canonical 5′ cap structure are produced during alphaviral replication and packaged into viral particles. However, the role/impact of the noncapped genomic RNA (ncgRNA) during alphaviral infection in vivo has yet to be characterized. To determine the importance of the ncgRNA in vivo, the previously described D355A and N376A nsP1 mutations, which increase or decrease nsP1 capping activity, respectively, were incorporated into the neurovirulent AR86 strain of Sindbis virus to enable characterization of the impact of altered capping efficiency in a murine model of infection. Mice infected with the N376A nsP1 mutant exhibited slightly decreased rates of mortality and delayed weight loss and neurological symptoms, although levels of inflammation in the brain were similar to those of wild-type infection. Although the D355A mutation resulted in decreased antiviral gene expression and increased resistance to interferon in vitro, mice infected with the D355A mutant showed significantly reduced mortality and morbidity compared to mice infected with wild-type virus. Interestingly, expression of proinflammatory cytokines was found to be significantly decreased in mice infected with the D355A mutant, suggesting that capping efficiency and the production of ncgRNA are vital to eliciting pathogenic levels of inflammation. Collectively, these data indicate that the ncgRNA have important roles during alphaviral infection and suggest a novel mechanism by which noncapped viral RNAs aid in viral pathogenesis. IMPORTANCE Mosquito-transmitted alphaviruses have been the cause of widespread outbreaks of disease that can range from mild illness to lethal encephalitis or severe polyarthritis. There are currently no safe and effective vaccines or therapeutics with which to prevent or treat alphaviral disease, highlighting the need to better understand alphaviral pathogenesis to develop novel antiviral strategies. This report reveals production of noncapped genomic RNAs (ncgRNAs) to be a novel determinant of alphaviral virulence and offers insight into the importance of inflammation to pathogenesis. Taken together, the findings reported here suggest that the ncgRNAs contribute to alphaviral pathogenesis through the sensing of the ncgRNAs during alphaviral infection and are necessary for the development of severe disease.

scholarly journals Mutations Conferring Aminoglycoside and Spectinomycin Resistance in Borrelia burgdorferi

2006 ◽  
Vol 50 (2) ◽  
pp. 445-452 ◽  
Author(s):  
Daniel Criswell ◽  
Virginia L. Tobiason ◽  
J. Stephen Lodmell ◽  
D. Scott Samuels
Keyword(s):  
16S Rrna ◽  
Borrelia Burgdorferi ◽  
Type Strain ◽  
Wild Type Strain ◽  
Small Subunit ◽  
Wild Type ◽  
Spectinomycin Resistance ◽  
E Coli ◽  
Resistant Mutants

ABSTRACT We have isolated and characterized in vitro mutants of the Lyme disease agent Borrelia burgdorferi that are resistant to spectinomycin, kanamycin, gentamicin, or streptomycin, antibiotics that target the small subunit of the ribosome. 16S rRNA mutations A1185G and C1186U, homologous to Escherichia coli nucleotides A1191 and C1192, conferred >2,200-fold and 1,300-fold resistance to spectinomycin, respectively. A 16S rRNA A1402G mutation, homologous to E. coli A1408, conferred >90-fold resistance to kanamycin and >240-fold resistance to gentamicin. Two mutations were identified in the gene for ribosomal protein S12, at a site homologous to E. coli residue Lys-87, in mutants selected in streptomycin. Substitutions at codon 88, K88R and K88E, conferred 7-fold resistance and 10-fold resistance, respectively, to streptomycin on B. burgdorferi. The 16S rRNA A1185G and C1186U mutations, associated with spectinomycin resistance, appeared in a population of B. burgdorferi parental strain B31 at a high frequency of 6 × 10−6. These spectinomycin-resistant mutants successfully competed with the wild-type strain during 100 generations of coculture in vitro. The aminoglycoside-resistant mutants appeared at a frequency of 3 × 10−9 to 1 ×10−7 in a population and were unable to compete with wild-type strain B31 after 100 generations. This is the first description of mutations in the B. burgdorferi ribosome that confer resistance to antibiotics. These results have implications for the evolution of antibiotic resistance, because the 16S rRNA mutations conferring spectinomycin resistance have no significant fitness cost in vitro, and for the development of new selectable markers.

scholarly journals STUDIES ON THE MECHANISM OF ENDOGENOUS PYROGEN PRODUCTION

1974 ◽  
Vol 140 (4) ◽  
pp. 954-964 ◽  
Author(s):  
Phyllis Bodel
Keyword(s):  
Protein Synthesis ◽  
Dose Response ◽  
Human Blood ◽  
Temperature Elevation ◽  
Blood Monocytes ◽  
Endogenous Pyrogen ◽  
Inhibitor Of Protein Synthesis ◽  
Relationship Of ◽  
Pyrogenic Activity

The characteristics of pyrogen production and release by human blood monocytes were investigated. A dose-response assay of monocyte pyrogen in rabbits indicated a linear relationship of temperature elevation to dose of pyrogen at lower doses. Monocytes did not contain pyrogen when first obtained, nor did they release it spontaneously even after 5 days of incubation in vitro. Pyrogen production was apparent 4 h after stimulation by endotoxin or phagocytosis, and continued for 24 h or more. Puromycin, an inhibitor of protein synthesis, prevented both initiation and continuation of pyrogen production and release. Pyrogen-containing supernates retained most pyrogenic activity during overnight incubation even in the presence of activated cells. Lymphocytes appeared to play no role in either initiation or continuation of pyrogen production in these studies.

scholarly journals The Impact of ALS-Associated Genes hnRNPA1, MATR3, VCP and UBQLN2 on the Severity of TDP-43 Aggregation

Cells ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1791
Author(s):  
Ana Bajc Česnik ◽  
Helena Motaln ◽  
Boris Rogelj
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Rna Binding ◽  
Neurodegenerative Disorder ◽  
Low Complexity ◽  
Wild Type ◽  
Disease Heterogeneity ◽  
Cytoplasmic Inclusions ◽  
The Impact ◽  
Lateral Sclerosis

Amyotrophic lateral sclerosis is a progressive neurodegenerative disorder, characterized by cytoplasmic inclusions of RNA-binding protein TDP-43. Despite decades of research and identification of more than 50 genes associated with amyotrophic lateral sclerosis (ALS), the cause of TDP-43 translocation from the nucleus and its aggregation in the cytoplasm still remains unknown. Our study addressed the impact of selected ALS-associated genes on TDP-43 aggregation behavior in wild-type and aggregation prone TDP-43 in vitro cell models. These were developed by deleting TDP-43 nuclear localization signal and stepwise shortening its low-complexity region. The SH-SY5Y cells were co-transfected with the constructs of aggregation-prone TDP-43 and wild-type or mutant ALS-associated genes hnRNPA1, MATR3, VCP or UBQLN2. The investigated genes displayed a unique impact on TDP-43 aggregation, generating distinct types of cytoplasmic inclusions, similar to those already described as resembling prion strains, which could represent the basis for neurodegenerative disease heterogeneity.

scholarly journals Effect of Borrelia burgdorferi OspC at the Site of Inoculation in Mouse Skin

2010 ◽  
Vol 78 (11) ◽  
pp. 4723-4733 ◽  
Author(s):  
Styliani Antonara ◽  
Laura Ristow ◽  
James McCarthy ◽  
Jenifer Coburn
Keyword(s):  
Borrelia Burgdorferi ◽  
Mouse Skin ◽  
Vascular Endothelial ◽  
Wild Type ◽  
Monocyte Chemoattractant Protein 1 ◽  
Monocyte Chemoattractant ◽  
Endothelial Growth Factor ◽  
Kinetics Of ◽  
Precise Role

ABSTRACT The Borrelia burgdorferi surface lipoprotein OspC is a critical virulence factor, but its precise role in the establishment of B. burgdorferi infection remains unclear. To determine whether OspC affects the host response at the site of inoculation of the bacterium, the recruitment of macrophages and neutrophils and the production of cytokines were examined at the site of infection by wild-type, ospC mutant, and complemented mutant B. burgdorferi strains. Of the 21 cytokines tested, monocyte chemoattractant protein 1 (MCP-1), keratinocyte-derived chemokine (KC, CXCL1), and vascular endothelial growth factor (VEGF) were found at increased levels at the site of inoculation of B. burgdorferi, and the levels varied with the production of OspC at one or more time points over the 1-week course of infection. The kinetics of expression and the dependence on OspC production by B. burgdorferi varied among the cytokines. The production of KC and MCP-1, and the appearance of monocytic infiltrates, correlated with the presence of the bacteria rather than with OspC specifically. In contrast, VEGF production was not correlated simply to the presence of the bacteria and is influenced by the presence of OspC. In in vitro assays, OspC and B. burgdorferi expressing OspC stimulated the growth of endothelial cells more than did the controls. These data suggest the possibility of a novel role for OspC in the life of B. burgdorferi at the interface of its mammalian and tick hosts.

Impact Deposition of Radon Progeny (218Po ,214Po and 210Po) on the Surface of Human Blood: In Vitro Study

2011 ◽  
Vol 110-116 ◽  
pp. 2004-2009 ◽  
Author(s):  
Asaad Hamid Ismail ◽  
Mohamad S. Jaafar
Keyword(s):  
Human Blood ◽  
Radon Concentration ◽  
Absorbed Dose ◽  
Blood Component ◽  
Good Efficiency ◽  
Present Design ◽  
Human Blood Samples ◽  
The Impact ◽  
Exposure Technique

This work presented new irradiation technique to estimate the impact of radon's progeny deposition on the human blood surface on some blood diseases, using CR-39Nuclear Track Detectors (NTDs). The results show that the present design has good efficiency and the loss rate of radon concentration was a little. Amount of the loss of radon concentration during the process of mixing blood component did not affect on the efficiency of exposure technique. Therefore, method of mixing blood component process was successful. As well as, human blood exposure to radon gas (2210±5.1Bq/m3) make thrombocytopenia, and no effect on red blood cell. And rate of radon absorbed dose into the human blood samples is high at 20 minutes.

scholarly journals Expression of LAIR-1 (CD305) on Human Blood Monocytes as a Marker of Hepatic Cirrhosis Progression

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
María Martínez-Esparza ◽  
Antonio José Ruiz-Alcaraz ◽  
Violeta Carmona-Martínez ◽  
María Dolores Fernández-Fernández ◽  
Gonzalo Antón ◽  
...  
Keyword(s):  
Liver Cirrhosis ◽  
Cell Surface ◽  
Human Blood ◽  
Total Content ◽  
Cell Surface Expression ◽  
Human Macrophage ◽  
Blood Monocytes ◽  
Cirrhotic Patients

Background and Aim. The presumed role of the inhibitory receptor LAIR-1 (CD305) in the inflammatory response suggests that it might contribute to the pathophysiology of chronic inflammatory diseases such as liver cirrhosis. We studied the LAIR-1 expression on liver macrophages and blood monocytes related to the progression of liver cirrhosis. Methods. The expression of LAIR-1 was analyzed by immunohistochemistry, flow cytometry, and Western blot. Results. We found a decreased number of macrophages expressing LAIR-1 in cirrhotic liver that could be due to a high presence of collagen, ligand of LAIR-1, in the fibrotic tissue which could downregulate its expression or interfere with the immunostaining. The expression of LAIR-1 decreased after cell differentiation, and the total content, but not the cell surface expression, increased after activation in the HL-60 human macrophage in vitro model. Blood monocytes exhibited higher LAIR-1 expression levels in cirrhotic patients, which were evident even in early clinical stages in all monocyte subsets, and greater in the “intermediate” inflammatory monocyte subpopulation. The in vitro activation of human blood monocytes did not increase its expression on the cell surface suggesting that the in vivo increase of LAIR-1 must be the result of a specific combination of stimuli present in cirrhotic patients. This represents an exclusive feature of liver cirrhosis, since blood monocytes from other chronic inflammatory pathologies showed similar or lower LAIR-1 levels compared with those of healthy controls. Conclusions. These results may indicate that monocyte LAIR-1 expression is a new biomarker to early detect liver damage caused by chronic inflammation in liver cirrhosis.

scholarly journals In-VitroDifferentiation of Mature Dendritic Cells From Human Blood Monocytes

1998 ◽  
Vol 6 (1-2) ◽  
pp. 25-39 ◽  
Author(s):  
Robert Gieseler ◽  
Dirk Heise ◽  
Afsaneh Soruri ◽  
Peter Schwartz ◽  
J. Hinrich Peters
Keyword(s):  
Dendritic Cells ◽  
Human Blood ◽  
T Cell Response ◽  
Blood Monocytes ◽  
Gm Csf ◽  
Hla Dr ◽  
Hla Dq ◽  
Specific Stimulation ◽  
Antigen Presenting

Representing the most potent antigen-presenting cells, dendritic cells (DC) can now be generated from human blood monocytes. We recently presented a novel protocol employing GM-CSF, IL-4, and IFN-γto differentiate monocyte-derived DCin vitro. Here, such cells are characterized in detail. Cells in culture exhibited both dendritic and veiled morphologies, the former being adherent and the latter suspended. Phenotypically, they were CD1a-/dim, CD11a+, CD11b++, CD11c+, CD14dim/-, CD16a-/dim, CD18+, CD32dim/-, CD33+, CD40+, CD45R0+, CD50+, CD54+, CD64-/dim, CD68+, CD71+, CD80dim, CD86+/++, MHC class I++/+++HLA-DR++/+++HLA-DP+, and HLA-DQ+. The DC stimulated a strong allogeneic T-cell response, and further evidence for their autologous antigen-specific stimulation is discussed. Although resembling a mature CD 11c+CD45R0+blood DC subset identified earlier, their differentiation in the presence of the Thl and Th2 cytokines IFN-γand IL-4 indicates that these DC may conform to mature mucosal DC.

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