Distinctive Evasion Mechanisms to Allow Persistence of Borrelia burgdorferi in Different Human Cell Lines

Lyme borreliosis is a multisystemic disease caused by the pleomorphic bacteria of the Borrelia burgdorferi sensu lato complex. The exact mechanisms for the infection to progress into a prolonged sequelae of the disease are currently unknown, although immune evasion and persistence of the bacteria in the host are thought to be major contributors. The current study investigated B. burgdorferi infection processes in two human cell lines, both non-immune and non-phagocytic, to further understand the mechanisms of infection of this bacterium. By utilizing light, confocal, helium ion, and transmission electron microscopy, borrelial infection of chondrosarcoma (SW1353) and dermal fibroblast (BJ) cells were examined from an early 30-min time point to a late 9-days post-infection. Host cell invasion, viability of both the host and B. burgdorferi, as well as, co-localization with lysosomes and the presence of different borrelial pleomorphic forms were analyzed. The results demonstrated differences of infection between the cell lines starting from early entry as B. burgdorferi invaded BJ cells in coiled forms with less pronounced host cell extensions, whereas in SW1353 cells, micropodial interactions with spirochetes were always seen. Moreover, infection of BJ cells increased in a dose dependent manner throughout the examined 9 days, while the percentage of infection, although dose dependent, decreased in SW1353 cells after reaching a peak at 48 h. Furthermore, blebs, round body and damaged B. burgdorferi forms, were mostly observed from the infected SW1353 cells, while spirochetes dominated in BJ cells. Both infected host cell lines grew and remained viable after 9 day post-infection. Although damaged forms were noticed in both cell lines, co-localization with lysosomes was low in both cell lines, especially in BJ cells. The invasion of non-phagocytic cells and the lack of cytopathic effects onto the host cells by B. burgdorferi indicated one mechanism of immune evasion for the bacteria. The differences in attachment, pleomorphic form expressions, and the lack of lysosomal involvement between the infected host cells likely explain the ability of a bacterium to adapt to different environments, as well as, a strategy for persistence inside a host.

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Comparison of Gamma Interferon-Mediated Antichlamydial Defense Mechanisms in Human and Mouse Cells

Infection and Immunity ◽

10.1128/iai.74.1.225-238.2006 ◽

2006 ◽

Vol 74 (1) ◽

pp. 225-238 ◽

Cited By ~ 86

Author(s):

Christine Roshick ◽

Heidi Wood ◽

Harlan D. Caldwell ◽

Grant McClarty

Keyword(s):

Nitric Oxide ◽

Cell Lines ◽

Human Cell ◽

Mouse Cell ◽

Gamma Interferon ◽

Host Cells ◽

Human Cell Lines ◽

Mouse Cells ◽

Ifn Γ ◽

Human And Mouse

ABSTRACT Gamma interferon (IFN-γ)-induced effector mechanisms have potent antichlamydial activities that are critical to host defense. The most prominent and well-studied effectors are indoleamine dioxygenase (IDO) and nitric oxide (NO) synthase. The relative contributions of these mechanisms as inhibitors of chlamydial in vitro growth have been extensively studied using different host cells, induction mechanisms, and chlamydial strains with conflicting results. Here, we have undertaken a comparative analysis of cytokine- and lipopolysaccharide (LPS)-induced IDO and NO using an extensive assortment of human and murine host cells infected with human and murine chlamydial strains. Following cytokine (IFN-γ or tumor necrosis factor alpha) and/or LPS treatment, the majority of human cell lines induced IDO but failed to produce NO. Conversely, the majority of mouse cell lines studied produced NO, not IDO. Induction of IDO in human cell lines inhibited growth of L2 and mouse pneumonitis agent, now referred to as Chlamydia muridarum MoPn equally in all but two lines, and inhibition was completely reversible by the addition of tryptophan. IFN-γ treatment of mouse cell lines resulted in substantially greater reduction of L2 than MoPn growth. However, despite elevated NO production by murine cells, blockage of NO synthesis with the l-arginine analogue N-monomethyl-l-arginine only partially rescued chlamydial growth, suggesting the presence of another IFN-γ-inducible antichlamydial mechanism unique to murine cells. Moreover, NO generated from the chemical nitric oxide donor sodium nitroprusside showed little direct effect on chlamydial infectivity or growth, indicating a natural resistance to NO. Finally, IFN-γ-inducible IDO expression in human HeLa cells was inhibited following exogenous NO treatment, resulting in a permissive environment for chlamydial growth. In summary, cytokine- and LPS-inducible effectors produced by human and mouse cells differ and, importantly, these host-specific effector responses result in chlamydial strain-specific antimicrobial activities.

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Host cell reactivation of gamma-irradiated adenovirus 5 in human cell lines of varying radiosensitivity

British Journal of Cancer ◽

10.1038/bjc.1992.226 ◽

1992 ◽

Vol 66 (1) ◽

pp. 113-118 ◽

Cited By ~ 13

Author(s):

JJ Eady ◽

JH Peacock ◽

TJ McMillan

Keyword(s):

Host Cell ◽

Cell Lines ◽

Human Cell ◽

Human Cell Lines ◽

Cell Reactivation ◽

Gamma Irradiated ◽

Host Cell Reactivation ◽

Adenovirus 5

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Release of ATP during host cell killing by enteropathogenicE. coliand its role as a secretory mediator

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.00484.2001 ◽

2002 ◽

Vol 283 (1) ◽

pp. G74-G86 ◽

Cited By ~ 55

Author(s):

John K. Crane ◽

Ruth A. Olson ◽

Heather M. Jones ◽

Michael E. Duffey

Keyword(s):

Conditioned Medium ◽

Cell Lines ◽

Human Cell ◽

Short Circuit ◽

Ussing Chamber ◽

Host Cells ◽

Watery Diarrhea ◽

Current Response ◽

Human Cell Lines ◽

Colon Cells

Enteropathogenic Escherichia coli (EPEC) causes severe, watery diarrhea in children. We investigated ATP release during EPEC-mediated killing of human cell lines and whether released adenine nucleotides function as secretory mediators. EPEC triggered a release of ATP from all human cell lines tested: HeLa, COS-7, and T84 (colon cells) as measured using a luciferase kit. Accumulation of ATP in the supernatant medium was enhanced if an inhibitor of 5′-ectonucleotidase was included and was further enhanced if an ATP-regenerating system was added. In the presence of the inhibitor/regenerator, ATP concentrations in the supernatant medium reached 1.5–2 μM 4 h after infection with wild-type EPEC strains. In the absence of the inhibitor/regenerator system, extracellular ATP was rapidly broken down to ADP, AMP, and adenosine. Conditioned medium from EPEC-infected cells triggered a brisk chloride secretory response in intestinal tissues studied in the Ussing chamber (rabbit distal colon and T84 cell monolayers), whereas conditioned medium from uninfected cells and sterile filtrates of EPEC bacteria did not. The short-circuit current response to EPEC-conditioned medium was completely reversed by adenosine receptor blockers, such as 8-( p-sulfophenyl)-theophylline and MRS1754. EPEC killing of host cells releases ATP, which is broken down to adenosine, which in turn stimulates secretion via apical adenosine A2breceptors. These findings provide new insight into how EPEC causes watery diarrhea.

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HEK293 Cell Line as a Platform to Produce Recombinant Proteins and Viral Vectors

Frontiers in Bioengineering and Biotechnology ◽

10.3389/fbioe.2021.796991 ◽

2021 ◽

Vol 9 ◽

Author(s):

Evan Tan ◽

Cara Sze Hui Chin ◽

Zhi Feng Sherman Lim ◽

Say Kong Ng

Keyword(s):

Host Cell ◽

Cell Lines ◽

Recombinant Proteins ◽

Human Cell ◽

Viral Vectors ◽

Animal Cell ◽

Hek293 Cells ◽

Human Cell Lines ◽

Post Translational Modifications ◽

Serum Free Suspension

Animal cell-based expression platforms enable the production of complex biomolecules such as recombinant proteins and viral vectors. Although most biotherapeutics are produced in animal cell lines, production in human cell lines is expanding. One important advantage of using human cell lines is the increased potential that the resulting biotherapeutics would carry more “human-like” post-translational modifications. Among the human cell lines, HEK293 is widely utilized due to its high transfectivity, rapid growth rate, and ability to grow in a serum-free, suspension culture. In this review, we discuss the use of HEK293 cells and its subtypes in the production of biotherapeutics. We also compare their usage against other commonly used host cell lines in each category of biotherapeutics and summarise the factors influencing the choice of host cell lines used.

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Novel Avian Pathogenic Escherichia coli Genes Responsible for Adhesion to Chicken and Human Cell Lines

Applied and Environmental Microbiology ◽

10.1128/aem.01068-20 ◽

2020 ◽

Vol 86 (20) ◽

Cited By ~ 1

Author(s):

Aamir Ali ◽

Rafał Kolenda ◽

Muhammad Moman Khan ◽

Jörg Weinreich ◽

Ganwu Li ◽

...

Keyword(s):

Escherichia Coli ◽

Cell Lines ◽

Human Cell ◽

Host Cells ◽

Intestinal Cell ◽

Economic Losses ◽

Human Cell Lines ◽

Content Type ◽

E Coli ◽

Commercial Poultry

ABSTRACT Avian pathogenic Escherichia coli (APEC) is a major bacterial pathogen of commercial poultry contributing to extensive economic losses and contamination of the food chain. One of the initial steps in bacterial infection and successful colonization of the host is adhesion to the host cells. A random transposon mutant library (n = 1,300) of APEC IMT 5155 was screened phenotypically for adhesion to chicken (CHIC-8E11) and human (LoVo) intestinal epithelial cell lines. The detection and quantification of adherent bacteria were performed by a modified APEC-specific antibody staining assay using fluorescence microscopy coupled to automated VideoScan technology. Eleven mutants were found to have significantly altered adhesion to the cell lines examined. Mutated genes in these 11 “adhesion-altered mutants” were identified by arbitrary PCR and DNA sequencing. The genes were amplified from wild-type APEC IMT 5155, cloned, and transformed into the respective adhesion-altered mutants, and complementation was determined in adhesion assays. Here, we report contributions of the fdtA, rluD, yjhB, ecpR, and fdeC genes of APEC in adhesion to chicken and human intestinal cell lines. Identification of the roles of these genes in APEC pathogenesis will contribute to prevention and control of APEC infections. IMPORTANCE Avian pathogenic E. coli is not only pathogenic for commercial poultry but can also cause foodborne infections in humans utilizing the same attachment and virulence mechanisms. Our aim was to identify genes of avian pathogenic E. coli involved in adhesion to chicken and human cells in order to understand the colonization and pathogenesis of these bacteria. In contrast to the recent studies based on genotypic and bioinformatics data, we have used a combination of phenotypic and genotypic approaches for identification of novel genes contributing to adhesion in chicken and human cell lines. Identification of adhesion factors remains important, as antibodies elicited against such factors have shown potential to block colonization and ultimately prevent disease as prophylactic vaccines. Therefore, the data will augment the understanding of disease pathogenesis and ultimately in designing strategies against the infections.

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Use of host cell reactivation of cisplatin-treated adenovirus 5 in human cell lines to detect repair of drug-treated DNA.

Chemico-Biological Interactions ◽

10.1016/0009-2797(89)90110-5 ◽

1989 ◽

Vol 71 (4) ◽

pp. 353-365 ◽

Cited By ~ 5

Author(s):

Kevin R. Maynard ◽

Louise K. Hosking ◽

Bridget T. Hill

Keyword(s):

Host Cell ◽

Cell Lines ◽

Human Cell ◽

Human Cell Lines ◽

Cell Reactivation ◽

Host Cell Reactivation ◽

Adenovirus 5

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Factor H Binding to PspC of Streptococcus pneumoniae Increases Adherence to Human Cell Lines In Vitro and Enhances Invasion of Mouse Lungs In Vivo

Infection and Immunity ◽

10.1128/iai.00474-07 ◽

2007 ◽

Vol 75 (8) ◽

pp. 4082-4087 ◽

Cited By ~ 32

Author(s):

Lisa R. Quin ◽

Chinwendu Onwubiko ◽

Quincy C. Moore ◽

Megumi Fujioka Mills ◽

Larry S. McDaniel ◽

...

Keyword(s):

Streptococcus Pneumoniae ◽

Epithelial Cells ◽

Cell Lines ◽

Human Cell ◽

Factor H ◽

Lung Epithelial Cells ◽

Host Cells ◽

Complement Factor ◽

Human Cell Lines

ABSTRACTPneumococcal surface protein C (PspC) binds to both human secretory immunoglobulin A (sIgA) and complement factor H (FH). FH, a regulator of the alternative pathway of complement, can also mediate adherence of different host cells. Since PspC contributes to adherence and invasion of host cells, we hypothesized that the interaction of PspC with FH may also mediate adherence of pneumococci to human cells. In this study, we investigated FH- and sIgA-mediated pneumococcal adherence to human cell lines in vitro. Adherence assays demonstrated that preincubation ofStreptococcus pneumoniaeD39 with FH increased adherence to human umbilical vein endothelial cells (HUVEC) 5-fold and to lung epithelial cells (SK-MES-1) 18-fold, relative to that of D39 without FH on the surface. The presence of sIgA enhanced adherence to SK-MES-1 6-fold and to pharyngeal epithelial cells (Detroit 562) 14-fold. Furthermore, sIgA had an additive effect on adherence to HUVEC; specifically, preincubation of D39 with both FH and sIgA led to a 21-fold increase in adherence. Finally, using a mouse model, we examined the significance of the FH-PspC interaction in pneumococcal nasal colonization and lung invasion. Mice intranasally infected with D39 preincubated with FH had increased bacteremia and lung invasion, but they had similar levels of nasopharyngeal colonization compared to that of mice challenged with D39 without FH.

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Increased oxidative stress and activated heat shock proteins in human cell lines by silver nanoparticles

Human & Experimental Toxicology ◽

10.1177/0960327114538988 ◽

2014 ◽

Vol 34 (3) ◽

pp. 315-323 ◽

Cited By ~ 20

Author(s):

L Xin ◽

J Wang ◽

Y Wu ◽

S Guo ◽

J Tong

Keyword(s):

Oxidative Stress ◽

Silver Nanoparticles ◽

Heat Shock ◽

Cell Lines ◽

Human Cell ◽

Hepg2 Cells ◽

Human Cell Lines ◽

Ag Nps ◽

Protein Levels ◽

Dose Dependent

Due to widely commercial applications of silver nanoparticles (Ag NPs), toxicity assessment of this NP is of great importance. This study aimed to investigate the oxidative stress and heat shock response of Ag NPs at different doses to A549 and HepG2 cells. After treatment with different concentrations of Ag NPs for 24 h, oxidative damage indicated by malondialdehyde (MDA), 8-epi-PGF2α, and 8-hydroxy-2′-deoxyguanosine (8-oxo-dG) concentrations and protein levels of heat shock protein A1A (HSPA1A) and heme oxygenase 1 (HO-1) were determined. Ag NPs induced dose-dependent increases in MDA, 8-epi-PGF2α, and 8-oxo-dG concentrations in both A549 and HepG2 cells. Stress-inducible HSPA1A and HO-1 were also significantly upregulated in a dose-dependent manner. A higher level of HSPA1A and HO-1 activation by Ag NPs occurred in HepG2 cells than that in A549 cells. Compared with that of HSPA1A, Ag NPs induced a stronger increase in protein level of HO-1 in both cell lines. Significant positive correlations between protein levels of HSPA1A and HO-1 and oxidative damage were also observed. In conclusion, Ag NPs could induce oxidative stress in human cell lines. In addition to the products of oxidative stress such as MDA and 8-oxo-dG, HSPs can be used as potential biomarkers in nanotoxicity assessment, especially HO-1.

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