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Sample records for ma104 cell infection

  1. The shift from low to high non-structural protein 1 expression in rotavirus-infected MA-104 cells

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    Laura Martinez-Alvarez

    2013-06-01

    Full Text Available A hallmark of group/species A rotavirus (RVA replication in MA-104 cells is the logarithmic increase in viral mRNAs that occurs four-12 h post-infection. Viral protein synthesis typically lags closely behind mRNA synthesis but continues after mRNA levels plateau. However, RVA non-structural protein 1 (NSP1 is present at very low levels throughout viral replication despite showing robust protein synthesis. NSP1 has the contrasting properties of being susceptible to proteasomal degradation, but being stabilised against proteasomal degradation by viral proteins and/or viral mRNAs. We aimed to determine the kinetics of the accumulation and intracellular distribution of NSP1 in MA-104 cells infected with rhesus rotavirus (RRV. NSP1 preferentially localises to the perinuclear region of the cytoplasm of infected cells, forming abundant granules that are heterogeneous in size. Late in infection, large NSP1 granules predominate, coincident with a shift from low to high NSP1 expression levels. Our results indicate that rotavirus NSP1 is a late viral protein in MA-104 cells infected with RRV, presumably as a result of altered protein turnover.

  2. ACUMULACIÓN DE LA PROTEÍNA DE CHOQUE TÉRMICO, HSC70, EN CÉLULAS MA104 DESPUÉS DE LA INFECCIÓN CON ROTAVIRUS Increase of heat shock cognate protein, HSC70, in MA104 cells following rotavirus infection

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    Diana Rocio Pulido Morera

    2007-12-01

    rotavirus particles during the infection of MA104 cells, but changes in the accumulation levels of this protein through the rotavirus infection cycle are unknown. Objetive. To determine if the accumulation levels of HSC70 in MA104 cells change during the infection by rotavirus. Materials and methods. Immunofluorescene microscopy, Western blotting an ELISA were used in order to determine HSC70 accumulation levels in MA104 cells after infection (0 up to 16 h p.i. by rotavirus strains Wa (human, Rf (bovine and RRV (simian. Additionally, a rabbit polyclonal serum against purified rotavirus particles was used for detecting rotavirus antigen in an immunoperoxidase assay. Results. The immunofluorescence staining of cells infected with each of three rotavirus strains showed a direct correlation between the increase of fluorescence in the cytoplasm and the increase of the viral antigen. The intensity of the cytoplasm fluorescence was 1.1 to 2.0 times higher in infected cells than that observed in control cells. On the other hand, the intensity of the fluorescence in the cell membrane was similar to that of the non-infected control cells. The Western blotting assay did not allow to establish measurable differences between infected and non-infected MA104 cells, because the increase of the protein are below the detection limit. According to the results of ELISA, HSC70 level increases 1 to 3 times in MA104 cells after (8 h p.i. the infection with strain RRV, whereas infection with strain RF produced an increase which ranged from 1.3 to 2.5 times after 10 h p.i. Infection by strain Wa was correlated with un increase of HSC70 level between 1.7 and 3.0 times after 2 h p.i. Conclusions. The results suggest that the increase of HSC70 accumulation level possibly corresponds to an increased expression of its gene during the rotavirus infection and probably it is involved in rotavirus multiplication steps additional to those of entry and exit processes.

  3. Isolation and propagation of the animal rotaviruses in MA-104 cells--30 years of practical experience.

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    Otto, Peter H; Reetz, Jochen; Eichhorn, Werner; Herbst, Werner; Elschner, Mandy C

    2015-10-01

    A total of 136 rotavirus positive samples from diarrhoeic animals of different species were submitted for isolation and cultural propagation of rotavirus on MA-104 cells. The samples were collected from animals with diarrhoea, between 1980 and 2010, originating from herds or farms located in several parts of Germany. Rotaviruses of species A were isolated from 102 faecal samples in cultures of MA-104 cells under the following conditions: pre-treatment of virus with trypsin, incorporation of trypsin into culture medium, use of roller cultures, and centrifugation of the samples on the cells. The cell culture adapted viruses produced a cytopathic effect, accompanied by the release of cells from the glass surface of the cultivation vessels. After 10 passages the virus isolates yielded titres between 10(5.5) and 10(7.5)ml(-1) TCID50. Isolation and serial propagation of the virus in MA-104 cells was confirmed by immunofluorescence assay, transmission electron microscopy, and polyacrylamide-gel electrophoresis of viral dsRNA. Eight (5.9%) of the electrophoretic profiles were characteristic of species B or D rotaviruses, which were not replicated in MA-104 cells.

  4. The tight junction protein JAM-A functions as coreceptor for rotavirus entry into MA104 cells.

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    Torres-Flores, Jesús M; Silva-Ayala, Daniela; Espinoza, Marco A; López, Susana; Arias, Carlos F

    2015-01-15

    Several molecules have been identified as receptors or coreceptors for rotavirus infection, including glycans, integrins, and hsc70. In this work we report that the tight junction proteins JAM-A, occludin, and ZO-1 play an important role during rotavirus entry into MA104 cells. JAM-A was found to function as coreceptor for rotavirus strains RRV, Wa, and UK, but not for rotavirus YM. Reassortant viruses derived from rotaviruses RRV and YM showed that the virus spike protein VP4 determines the use of JAM-A as coreceptor.

  5. 犬瘟热病毒在MA-104、Marc-145、Vero3种细胞内增殖效果的比较%Comparison on Multiplication Effect of Canine Distemper Virus in MA-104, Marc-145, and Vero Cells

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    王朝蕾; 崔卓宇; 吕永钢; 胡江锋; 焦铁军; 樊军喜; 王根红; 崔瑞宁

    2012-01-01

    试验比较了MA-104、Marc-145、Vero3种猴肾细胞增殖犬瘟热病毒的敏感性,按常规方法将犬瘟热病毒(CDV—XN112株)分别接种于MA-104、Marc-145、Vero3种细胞,通过观察细胞病变,确定收毒时间,比较病毒滴度。结果表明,犬瘟热病毒可在MA-104、Marc-145、Vero3种细胞内增殖,并出现典型细胞病变,效价均达到10^4.5TCID50/0.1mL以上.而Vero细胞增殖犬瘟热病毒更为经济高效,是增殖该病毒的理想细胞。%After canine distemper virus (CDV-XN 112 strain) was inoculated into MA- 104, Marc- 145 and Vero cells, the sensitivity of three types of monkey kidney to CDV was compared by observing cell pathological effect, determining the time for harvesting virus and comparing virus titers. The results showed that three cells were suitable for CDV, with typical cell pathological effect, and the titers of virus harvest fluids were more than 104.5 TCID50/0. lmL, among them Vero cell was more cost-effective and ideal for proliferation CDV.

  6. The cultural properties in MA-104 cell and establishment of FQ-PCR diagnostic method for porcine rotavirus%猪轮状病毒的细胞培养特性与FQ-PCR检测方法的建立

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    魏锁成; 巩转娣; 宋昌军

    2011-01-01

    To explore isolation conditions and culture properties of rotavirus and establish Real time fluorescence quantitative PCR(FQ-PCR) diagnostic method for porcine rotatirus(PRV).MA-104 cells were cultured in the three mediums to decide the optimum one.The positive fecal samples detected by ELISA in diarrhea piglets were cultured in group C medium 5% CO2 at 37℃.MA-104 cells were inoculated with rotavirus,the rotavirus was isolated and purified, VP6 gene nucleotides of the separated rotavirus strains were sequenced, the homology of VP6 gene was blasted with the standard porcine rotavirus (PRV) strain(AV-55).Real time FQ-PCR diagnostic method for porcine rotatirus has been established.The MA-104 cells pasted wall and grew quickly with low costs when cultured in group C culture medium.the optium culture conditions of rotavirus was 5 % CO2 at 37℃.Cells appeared some clear cytopathic effects (CPE) after 18 h of inoculation,such as cell shrinking and integrating,cell layer splitting, vacuolization and nuclear karyopyknosis ect.The rotaviruss were received when CPE reached 90 %.One rotavirus strains(GSPRV01 strain) was isolated and identified as PRV through VP6 nucleotide sequencing.Its homology was up to 88.50% with PRV reference strains (AV-55).PRV grows well in MA104 at 37℃ and 5%CO2.The homology of GSPRV01 strain is 88.50% with reference strain.FQ-PCR detection methods has been established.%为了探讨动物轮状病毒的细胞培养特性和分离方法,建立FQ-PCR检测方法,旨在为研发诊断试剂盒和疫苗莫定基础.37℃5%CO2下用细胞培养液C培养ELISA检测的阳性猪粪便样本,观察细胞形态的变化;用RV感染MA-104细胞,分离纯化病毒,测定VP6基因序列并分析其同源性,在普通PCR和实时定量PCR的基础上,建立FQ-PCR检测方法.结果,MA-104细胞培养的最佳条件为37℃5%CO2 ;接毒后18 h出现细胞膜缩融合、细胞层裂开、细胞核固缩及空泡化等

  7. The effect of concanavalin A on the replication of rotavirus (SA-11 in cell culture

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    Hasenack Beatriz S.

    2002-01-01

    Full Text Available Rotavirus (RV strain SA-11 was studied with respect to its infectivity in MA-104 cell cultures and the effect of concanavalin A (ConA. Receptors for ConA at the surface of MA-104 cell were determined by fluorescence assay and specifically inhibited by D-mannose. The kinetics of virus growth was carried out by plaque assay. Electron microscopy and polyacrylamide gel electrophoresis were used for monitoring the experiments. It was concluded that RV replication was not affected consistently by ConA, however it interfered with the development of cytopathic effect (CPE without altering virus yields.

  8. Infectious rotavirus enters cells by direct cell membrane penetration, not by endocytosis

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    Kaljot, K.T.; Shaw, R.D.; Greenberg, H.B. (Stanford Univ. School of Medicine, CA (USA) Palo Alto Veterans Administration Medical Center, CA (USA)); Rubin, D.H. (Univ. of Pennsylvania, Philadelphia (USA))

    1988-04-01

    Rotaviruses are icosahedral viruses with a segmented, double-stranded RNA genome. They are the major cause of severe infantile infectious diarrhea. Rotavirus growth in tissue culture is markedly enhanced by pretreatment of virus with trypsin. Trypsin activation is associated with cleavage of the viral hemagglutinin (viral protein 3 (VP3); 88 kilodaltons) into two fragments (60 and 28 kilodaltons). The mechanism by which proteolytic cleavage leads to enhanced growth is unknown. To determine whether trypsin treatment affected rotavirus internalization, the authors studied the kinetics of entry of infectious rhesus rotavirus (RRV) into MA104 cells. Trypsin-activated RRV was internalized with a half-time of 3 to 5 min, while nonactivated virus disappeared from the cell surface with a half-time of 30 to 50 min. In contrast to trypsin-activated RRV, loss of nonactivated RRV from the cell surface did not result in the appearance of infection, as measured by plaque formation. Purified trypsin-activated RRV added to cell monolayers at pH 7.4 mediated {sup 51}Cr, ({sup 14}C)choline, and ({sup 3}H)inositol released from prelabeled MA104 cells. This release could be specifically blocked by neutralizing antibodies to VP3. These results suggest that MA104 cell infection follows the rapid entry of trypsin-activated RRV by direct cell membrane penetration. Cell membrane penetration of infectious RRV is initiated by trypsin cleavage of VP3. Neutralizing antibodies can inhibit this direct membrane penetration.

  9. Susceptibility of various cell lines to Neospora caninum tachyzoites cultivation

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    Khordadmehr, M.,

    2014-05-01

    Full Text Available Neospora caninum is a coccidian protozoan parasite which is a major cause of bovine abortions and neonatal mortality in cattle, sheep, goat and horse. Occasionally, cultured cells are used for isolation and multiplication of the agent in vitro with several purposes. In this study the tachyzoite yields of N. caninum were compared in various cell cultures as the host cell lines. Among the cell cultures tested, two presented good susceptibility to the agent: cell lines Vero and MA-104. SW742 and TLI (in vitro suspension culture of lymphoid cells infected with Theileria lestoquardi showed moderate sensitivity. No viable tachyzoite were detected in the culture of MDCK and McCoy cell lines. These results demonstrate that MA-104 and SW742 cells present adequate susceptibility to N. caninum compared to Vero cells, which have been largely used to multiply the parasite in vitro. Moreover, these have easy manipulation, fast multiplication and relatively low nutritional requirements. In addition, the result of this study showed that TLI cell line as a suspension cell culture is susceptible to Nc-1 tachyzoites infection and could be used as an alternative host cell line for tachyzoites culture in vitro studies.

  10. NK Cells and Poxvirus infection

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    Deborah N. Burshtyn

    2013-01-01

    Full Text Available In recent years our understanding of the role of NK cells in the response to viral infection has grown rapidly. Not only do we realize viruses have many immune evasion strategies to escape NK cell responses, but that stimulation of NK cell subsets during an antiviral response occurs through receptors seemingly geared directly at viral products and that NK cells can provide a memory response to viral pathogens. Tremendous knowledge has been gained in this area through the study of Herpes viruses, but appreciation for the significance of NK cells in the response to other types of viral infections is growing. The function of NK cells in defense against poxviruses has emerged over several decades beginning with the early seminal studies showing the role of NK cells and the NK gene complex in susceptibility of mouse strains to Ectromelia, a poxvirus pathogen of mice. More recently, greater understanding has emerged of the molecular details of the response. Given that human diseases caused by poxviruses can be as lethal as smallpox or as benign as Molluscum contagiosum, and that Vaccinia virus, the prototypic member of the pox family, persists as a mainstay of vaccine design and has potential as an oncolytic virus for tumor therapy, further research in this area remains important. This review focuses on recent advances in understanding the role of NK cells in the immune response to poxviruses, the receptors involved in activation of NK cells during poxvirus infection, and the viral evasion strategies poxviruses employ to avoid the NK response.

  11. Mast cells in viral infections

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    Piotr Witczak

    2012-04-01

    Full Text Available  There are some premises suggesting that mast cells are involved in the mechanisms of anti-virus defense and in viral disease pathomechanisms. Mast cells are particularly numerous at the portals of infections and thus may have immediate and easy contact with the external environment and invading pathogens. These cells express receptors responsible for recognition of virus-derived PAMP molecules, mainly Toll-like receptors (TLR3, TLR7/8 and TLR9, but also RIG-I-like and NOD-like molecules. Furthermore, mast cells generate various mediators, cytokines and chemokines which modulate the intensity of inflammation and regulate the course of innate and adaptive anti-viral immunity. Indirect evidence for the role of mast cells in viral infections is also provided by clinical observations and results of animal studies. Currently, more and more data indicate that mast cells can be infected by some viruses (dengue virus, adenoviruses, hantaviruses, cytomegaloviruses, reoviruses, HIV-1 virus. It is also demonstrated that mast cells can release pre formed mediators as well as synthesize de novo eicosanoids in response to stimulation by viruses. Several data indicate that virus-stimulated mast cells secrete cytokines and chemokines, including interferons as well as chemokines with a key role in NK and Tc lymphocyte influx. Moreover, some information indicates that mast cell stimulation via TLR3, TLR7/8 and TLR9 can affect their adhesion to extracellular matrix proteins and chemotaxis, and influence expression of some membrane molecules. Critical analysis of current data leads to the conclusion that it is not yet possible to make definitive statements about the role of mast cells in innate and acquired defense mechanisms developing in the course of viral infection and/or pathomechanisms of viral diseases.

  12. Mast cells in viral infections

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    Piotr Witczak; Ewa Brzezińska-Błaszczyk

    2012-01-01

     There are some premises suggesting that mast cells are involved in the mechanisms of anti-virus defense and in viral disease pathomechanisms. Mast cells are particularly numerous at the portals of infections and thus may have immediate and easy contact with the external environment and invading pathogens. These cells express receptors responsible for recognition of virus-derived PAMP molecules, mainly Toll-like receptors (TLR3, TLR7/8 and TLR9), but also RIG-I-like and NOD-like molecules. Fu...

  13. Latent herpesvirus infection arms NK cells.

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    White, Douglas W; Keppel, Catherine R; Schneider, Stephanie E; Reese, Tiffany A; Coder, James; Payton, Jacqueline E; Ley, Timothy J; Virgin, Herbert W; Fehniger, Todd A

    2010-06-03

    Natural killer (NK) cells were identified by their ability to kill target cells without previous sensitization. However, without an antecedent "arming" event, NK cells can recognize, but are not equipped to kill, target cells. How NK cells become armed in vivo in healthy hosts is unclear. Because latent herpesviruses are highly prevalent and alter multiple aspects of host immunity, we hypothesized that latent herpesvirus infection would arm NK cells. Here we show that NK cells from mice latently infected with Murid herpesvirus 4 (MuHV-4) were armed as evidenced by increased granzyme B protein expression, cytotoxicity, and interferon-gamma production. NK-cell arming occurred rapidly in the latently infected host and did not require acute viral infection. Furthermore, NK cells armed by latent infection protected the host against a lethal lymphoma challenge. Thus, the immune environment created by latent herpesvirus infection provides a mechanism whereby host NK-cell function is enhanced in vivo.

  14. Parvovirus infection-induced cell death and cell cycle arrest

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    Chen, Aaron Yun; Qiu, Jianming

    2011-01-01

    The cytopathic effects induced during parvovirus infection have been widely documented. Parvovirus infection-induced cell death is often directly associated with disease outcomes (e.g., anemia resulting from loss of erythroid progenitors during parvovirus B19 infection). Apoptosis is the major form of cell death induced by parvovirus infection. However, nonapoptotic cell death, namely necrosis, has also been reported during infection of the minute virus of mice, parvovirus H-1 and bovine parvovirus. Recent studies have revealed multiple mechanisms underlying the cell death during parvovirus infection. These mechanisms vary in different parvoviruses, although the large nonstructural protein (NS)1 and the small NS proteins (e.g., the 11 kDa of parvovirus B19), as well as replication of the viral genome, are responsible for causing infection-induced cell death. Cell cycle arrest is also common, and contributes to the cytopathic effects induced during parvovirus infection. While viral NS proteins have been indicated to induce cell cycle arrest, increasing evidence suggests that a cellular DNA damage response triggered by an invading single-stranded parvoviral genome is the major inducer of cell cycle arrest in parvovirus-infected cells. Apparently, in response to infection, cell death and cell cycle arrest of parvovirus-infected cells are beneficial to the viral cell lifecycle (e.g., viral DNA replication and virus egress). In this article, we will discuss recent advances in the understanding of the mechanisms underlying parvovirus infection-induced cell death and cell cycle arrest. PMID:21331319

  15. Dengue Virus Infection Perturbs Lipid Homeostasis in Infected Mosquito Cells

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    Perera, Rushika M.; Riley, Catherine; Isaac, Georgis; Hopf- Jannasch, Amber; Moore, Ronald J.; Weitz, Karl K.; Pasa-Tolic, Ljiljana; Metz, Thomas O.; Adamec, Jiri; Kuhn, Richard J.

    2012-03-22

    Dengue virus causes {approx}50-100 million infections per year and thus is considered one of the most aggressive arthropod-borne human pathogen worldwide. During its replication, dengue virus induces dramatic alterations in the intracellular membranes of infected cells. This phenomenon is observed both in human and vector-derived cells. Using high-resolution mass spectrometry of mosquito cells, we show that this membrane remodeling is directly linked to a unique lipid repertoire induced by dengue virus infection. Specifically, 15% of the metabolites detected were significantly different between DENV infected and uninfected cells while 85% of the metabolites detected were significantly different in isolated replication complex membranes. Furthermore, we demonstrate that intracellular lipid redistribution induced by the inhibition of fatty acid synthase, the rate-limiting enzyme in lipid biosynthesis, is sufficient for cell survival but is inhibitory to dengue virus replication. Lipids that have the capacity to destabilize and change the curvature of membranes as well as lipids that change the permeability of membranes are enriched in dengue virus infected cells. Several sphingolipids and other bioactive signaling molecules that are involved in controlling membrane fusion, fission, and trafficking as well as molecules that influence cytoskeletal reorganization are also up regulated during dengue infection. These observations shed light on the emerging role of lipids in shaping the membrane and protein environments during viral infections and suggest membrane-organizing principles that may influence virus-induced intracellular membrane architecture.

  16. Dengue virus infection perturbs lipid homeostasis in infected mosquito cells.

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    Rushika Perera

    Full Text Available Dengue virus causes ∼50-100 million infections per year and thus is considered one of the most aggressive arthropod-borne human pathogen worldwide. During its replication, dengue virus induces dramatic alterations in the intracellular membranes of infected cells. This phenomenon is observed both in human and vector-derived cells. Using high-resolution mass spectrometry of mosquito cells, we show that this membrane remodeling is directly linked to a unique lipid repertoire induced by dengue virus infection. Specifically, 15% of the metabolites detected were significantly different between DENV infected and uninfected cells while 85% of the metabolites detected were significantly different in isolated replication complex membranes. Furthermore, we demonstrate that intracellular lipid redistribution induced by the inhibition of fatty acid synthase, the rate-limiting enzyme in lipid biosynthesis, is sufficient for cell survival but is inhibitory to dengue virus replication. Lipids that have the capacity to destabilize and change the curvature of membranes as well as lipids that change the permeability of membranes are enriched in dengue virus infected cells. Several sphingolipids and other bioactive signaling molecules that are involved in controlling membrane fusion, fission, and trafficking as well as molecules that influence cytoskeletal reorganization are also up regulated during dengue infection. These observations shed light on the emerging role of lipids in shaping the membrane and protein environments during viral infections and suggest membrane-organizing principles that may influence virus-induced intracellular membrane architecture.

  17. Coronavirus infection of polarized epithelial cells

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    Rossen, J W; Horzinek, M C; Rottier, P J

    1995-01-01

    Epithelial cells are the first host cells to be infected by incoming c oronaviruses. Recent observations in vitro show that coronaviruses are released from a specific side of these polarized cells, and this polarized release might be important for the spread of the infection in vivo. Mechanisms for

  18. HCV Infection and B-Cell Lymphomagenesis

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    Masahiko Ito

    2011-01-01

    Full Text Available Hepatitis C virus (HCV has been recognized as a major cause of chronic liver diseases worldwide. It has been suggested that HCV infects not only hepatocytes but also mononuclear lymphocytes including B cells that express the CD81 molecule, a putative HCV receptor. HCV infection of B cells is the likely cause of B-cell dysregulation disorders such as mixed cryoglobulinemia, rheumatoid factor production, and B-cell lymphoproliferative disorders that may evolve into non-Hodgkin's lymphoma (NHL. Epidemiological data indicate an association between HCV chronic infection and the occurrence of B-cell NHL, suggesting that chronic HCV infection is associated at least in part with B-cell lymphomagenesis. In this paper, we aim to provide an overview of recent literature, including our own, to elucidate a possible role of HCV chronic infection in B-cell lymphomagenesis.

  19. In-cell infection: a novel pathway for Epstein-Barr virus infection mediated by cell-in-cell structures.

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    Ni, Chao; Chen, Yuhui; Zeng, Musheng; Pei, Rongjuan; Du, Yong; Tang, Linquan; Wang, Mengyi; Hu, Yazhuo; Zhu, Hanyu; He, Meifang; Wei, Xiawei; Wang, Shan; Ning, Xiangkai; Wang, Manna; Wang, Jufang; Ma, Li; Chen, Xinwen; Sun, Qiang; Tang, Hong; Wang, Ying; Wang, Xiaoning

    2015-07-01

    Epstein-Barr virus (EBV) can infect both susceptible B lymphocytes and non-susceptible epithelial cells (ECs). Viral tropism analyses have revealed two intriguing means of EBV infection, either by a receptor-mediated infection of B cells or by a cell-to-cell contact-mediated infection of non-susceptible ECs. Herein, we report a novel "in-cell infection" mechanism for EBV infection of non-susceptible ECs through the formation of cell-in-cell structures. Epithelial CNE-2 cells were invaded by EBV-infected Akata B cells to form cell-in-cell structures in vitro. Such unique cellular structures could be readily observed in the specimens of nasopharyngeal carcinoma. Importantly, the formation of cell-in-cell structures led to the autonomous activation of EBV within Akata cells and subsequent viral transmission to CNE-2 cells, as evidenced by the expression of viral genes and the presence of virion particles in CNE-2 cells. Significantly, EBV generated from in-cell infected ECs displayed altered tropism with higher infection efficacy to both B cells and ECs. In addition to CNE-2 tumor cells, cell-in-cell structure formation could also mediate EBV infection of NPEC1-Bmi1 cells, an immortalized nasopharyngeal epithelial cell line. Furthermore, efficient infection by this mechanism involved the activation of the PI3K/AKT signaling pathway. Thus, our study identified "in-cell infection" as a novel mechanism for EBV infection. Given the diversity of virus-infected cells and the prevalence of cell-in-cell structures during chronic infection, we speculate that "in-cell infection" is likely a general mechanism for EBV and other viruses to infect non-susceptible ECs.

  20. Murid herpesvirus-4 exploits dendritic cells to infect B cells.

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    Gaspar, Miguel; May, Janet S; Sukla, Soumi; Frederico, Bruno; Gill, Michael B; Smith, Christopher M; Belz, Gabrielle T; Stevenson, Philip G

    2011-11-01

    Dendritic cells (DCs) play a central role in initiating immune responses. Some persistent viruses infect DCs and can disrupt their functions in vitro. However, these viruses remain strongly immunogenic in vivo. Thus what role DC infection plays in the pathogenesis of persistent infections is unclear. Here we show that a persistent, B cell-tropic gamma-herpesvirus, Murid Herpesvirus-4 (MuHV-4), infects DCs early after host entry, before it establishes a substantial infection of B cells. DC-specific virus marking by cre-lox recombination revealed that a significant fraction of the virus latent in B cells had passed through a DC, and a virus attenuated for replication in DCs was impaired in B cell colonization. In vitro MuHV-4 dramatically altered the DC cytoskeleton, suggesting that it manipulates DC migration and shape in order to spread. MuHV-4 therefore uses DCs to colonize B cells.

  1. Fungal cell gigantism during mammalian infection.

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    Oscar Zaragoza

    2010-06-01

    Full Text Available The interaction between fungal pathogens with the host frequently results in morphological changes, such as hyphae formation. The encapsulated pathogenic fungus Cryptococcus neoformans is not considered a dimorphic fungus, and is predominantly found in host tissues as round yeast cells. However, there is a specific morphological change associated with cryptococcal infection that involves an increase in capsule volume. We now report another morphological change whereby gigantic cells are formed in tissue. The paper reports the phenotypic characterization of giant cells isolated from infected mice and the cellular changes associated with giant cell formation. C. neoformans infection in mice resulted in the appearance of giant cells with cell bodies up to 30 microm in diameter and capsules resistant to stripping with gamma-radiation and organic solvents. The proportion of giant cells ranged from 10 to 80% of the total lung fungal burden, depending on infection time, individual mice, and correlated with the type of immune response. When placed on agar, giant cells budded to produce small daughter cells that traversed the capsule of the mother cell at the speed of 20-50 m/h. Giant cells with dimensions that approximated those in vivo were observed in vitro after prolonged culture in minimal media, and were the oldest in the culture, suggesting that giant cell formation is an aging-dependent phenomenon. Giant cells recovered from mice displayed polyploidy, suggesting a mechanism by which gigantism results from cell cycle progression without cell fission. Giant cell formation was dependent on cAMP, but not on Ras1. Real-time imaging showed that giant cells were engaged, but not engulfed by phagocytic cells. We describe a remarkable new strategy for C. neoformans to evade the immune response by enlarging cell size, and suggest that gigantism results from replication without fission, a phenomenon that may also occur with other fungal pathogens.

  2. Fungal cell gigantism during mammalian infection.

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    Zaragoza, Oscar; García-Rodas, Rocío; Nosanchuk, Joshua D; Cuenca-Estrella, Manuel; Rodríguez-Tudela, Juan Luis; Casadevall, Arturo

    2010-01-01

    The interaction between fungal pathogens with the host frequently results in morphological changes, such as hyphae formation. The encapsulated pathogenic fungus Cryptococcus neoformans is not considered a dimorphic fungus, and is predominantly found in host tissues as round yeast cells. However, there is a specific morphological change associated with cryptococcal infection that involves an increase in capsule volume. We now report another morphological change whereby gigantic cells are formed in tissue. The paper reports the phenotypic characterization of giant cells isolated from infected mice and the cellular changes associated with giant cell formation. C. neoformans infection in mice resulted in the appearance of giant cells with cell bodies up to 30 microm in diameter and capsules resistant to stripping with gamma-radiation and organic solvents. The proportion of giant cells ranged from 10 to 80% of the total lung fungal burden, depending on infection time, individual mice, and correlated with the type of immune response. When placed on agar, giant cells budded to produce small daughter cells that traversed the capsule of the mother cell at the speed of 20-50 m/h. Giant cells with dimensions that approximated those in vivo were observed in vitro after prolonged culture in minimal media, and were the oldest in the culture, suggesting that giant cell formation is an aging-dependent phenomenon. Giant cells recovered from mice displayed polyploidy, suggesting a mechanism by which gigantism results from cell cycle progression without cell fission. Giant cell formation was dependent on cAMP, but not on Ras1. Real-time imaging showed that giant cells were engaged, but not engulfed by phagocytic cells. We describe a remarkable new strategy for C. neoformans to evade the immune response by enlarging cell size, and suggest that gigantism results from replication without fission, a phenomenon that may also occur with other fungal pathogens.

  3. Human immunodeficiency virus type 1 infection of human uterine epithelial cells: viral shedding and cell contact-mediated infectivity.

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    Asin, Susana N; Wildt-Perinic, Dunja; Mason, Sarah I; Howell, Alexandra L; Wira, Charles R; Fanger, Michael W

    2003-05-15

    We examined the mechanism of human immunodeficiency virus (HIV) type 1 infection of human uterine epithelial cells to gain a clearer understanding of the events by which HIV-1 infects cells within the female reproductive tract. We demonstrated that these cells can be productively infected by HIV-1 and that infection is associated with viral RNA reverse transcription, DNA transcription, and secretion of infectious virus. Levels of viral DNA and secreted virus decreased gradually after infection. Moreover, virus released by the uterine epithelial cells shortly after infection was able to infect human T cell lines, but virus released later did not. In contrast, human CD4(+) T cell lines were infected after cocultivation with epithelial cells at both early and late stages of infection. These data demonstrated that HIV-1 infects human epithelial cells of upper reproductive tract origin and that productive viral infection of epithelial cells may be an important mechanism of transmission of HIV-1 infection in women.

  4. NKT cells in HIV-1 infection

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Natural killer T (NKT) cells are a unique T cell population that have important immunoregulatory functions and have been shown to be involved in host immunity against a range of microorganisms. It also emerges that they might play a role in HIV-1 infection, and therefore be selectively depleted during the early stages of infection. Recent studies are reviewed regarding the dynamics of NKT depletion during HIV-I infection and their recovery under highly active antiretrovirai treatment (HAART). Possible mechanisms for these changes are proposed based on the recent developments in HIV pathogenesis. Further discussions are focused on HIV's disruption of NKT activation by downregulating CDId expression on antigen presentation cells (APC). HIV-1 protein Nefis found to play the major role by interrupting the intraceilular trafficking of nascent and recycling CDId molecules.

  5. Cryptosporidium cell culture infectivity assay design.

    Science.gov (United States)

    King, B J; Keegan, A R; Robinson, B S; Monis, P T

    2011-05-01

    Members of the genus Cryptosporidium, which cause the gastrointestinal disease cryptosporidiosis, still represent a significant cause of water-borne disease worldwide. While intensive efforts have been invested in the development of techniques for parasite culture, in vitro growth has been hampered by a number of factors including low levels of infectivity as well as delayed life-cycle development and poor synchronicity. In this study we examined factors affecting the timing of contact between excysted sporozoites and target host cells and the subsequent impact of this upon the establishment of infection. We demonstrate that excystation rate impacts upon establishment of infection and that in our standard assay format the majority of sporozoites are not close enough to the cell monolayer when they are released from the oocyst to successfully establish infection. However, this can be easily overcome by centrifugation of oocysts onto the cell monolayer, resulting in approximately 4-fold increases in sporozoite attachment and subsequent infection. We further demonstrate that excystation procedures can be tailored to control excystation rate to match the assay end purpose and that excystation rate can influence data interpretation. Finally, the addition of both a centrifugation and washing step post-sporozoite attachment may be appropriate when considering the design of in vitro culture experiments for developmental analysis and stage-specific gene expression as this appears to increase the synchronicity of early developmental stages.

  6. Alteration of cell cycle progression by Sindbis virus infection

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Ruirong; Saito, Kengo [Department of Molecular Virology, Graduate School of Medicine, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chiba 260-8670 (Japan); Isegawa, Naohisa [Laboratory Animal Center, Graduate School of Medicine, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chiba 260-8670 (Japan); Shirasawa, Hiroshi, E-mail: sirasawa@faculty.chiba-u.jp [Department of Molecular Virology, Graduate School of Medicine, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chiba 260-8670 (Japan)

    2015-07-10

    We examined the impact of Sindbis virus (SINV) infection on cell cycle progression in a cancer cell line, HeLa, and a non-cancerous cell line, Vero. Cell cycle analyses showed that SINV infection is able to alter the cell cycle progression in both HeLa and Vero cells, but differently, especially during the early stage of infection. SINV infection affected the expression of several cell cycle regulators (CDK4, CDK6, cyclin E, p21, cyclin A and cyclin B) in HeLa cells and caused HeLa cells to accumulate in S phase during the early stage of infection. Monitoring SINV replication in HeLa and Vero cells expressing cell cycle indicators revealed that SINV which infected HeLa cells during G{sub 1} phase preferred to proliferate during S/G{sub 2} phase, and the average time interval for viral replication was significantly shorter in both HeLa and Vero cells infected during G{sub 1} phase than in cells infected during S/G{sub 2} phase. - Highlights: • SINV infection was able to alter the cell cycle progression of infected cancer cells. • SINV infection can affect the expression of cell cycle regulators. • SINV infection exhibited a preference for the timing of viral replication among the cell cycle phases.

  7. Cells in Dengue Virus Infection In Vivo

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    Sansanee Noisakran

    2010-01-01

    Full Text Available Dengue has been recognized as one of the most important vector-borne emerging infectious diseases globally. Though dengue normally causes a self-limiting infection, some patients may develop a life-threatening illness, dengue hemorrhagic fever (DHF/dengue shock syndrome (DSS. The reason why DHF/DSS occurs in certain individuals is unclear. Studies in the endemic regions suggest that the preexisting antibodies are a risk factor for DHF/DSS. Viremia and thrombocytopenia are the key clinical features of dengue virus infection in patients. The amounts of virus circulating in patients are highly correlated with severe dengue disease, DHF/DSS. Also, the disturbance, mainly a transient depression, of hematological cells is a critical clinical finding in acute dengue patients. However, the cells responsible for the dengue viremia are unresolved in spite of the intensive efforts been made. Dengue virus appears to replicate and proliferate in many adapted cell lines, but these in vitro properties are extremely difficult to be reproduced in primary cells or in vivo. This paper summarizes reports on the permissive cells in vitro and in vivo and suggests a hematological cell lineage for dengue virus infection in vivo, with the hope that a new focus will shed light on further understanding of the complexities of dengue disease.

  8. B-cell responses to HIV infection.

    Science.gov (United States)

    Moir, Susan; Fauci, Anthony S

    2017-01-01

    The induction of neutralizing antibodies directed against the human immunodeficiency virus (HIV) has received considerable attention in recent years, in part driven by renewed interest and opportunities for antibody-based strategies for prevention such as passive transfer of antibodies and the development of preventive vaccines, as well as immune-based therapeutic interventions. Advances in the ability to screen, isolate, and characterize HIV-specific antibodies have led to the identification of a new generation of potent broadly neutralizing antibodies (bNAbs). The majority of these antibodies have been isolated from B cells of chronically HIV-infected individuals with detectable viremia. In this review, we provide insight into the phenotypic and functional attributes of human B cells, with a focus on HIV-specific memory B cells and plasmablasts/cells that are responsible for sustaining humoral immune responses against HIV. We discuss the abnormalities in B cells that occur in HIV infection both in the peripheral blood and lymphoid tissues, especially in the setting of persisting viremia. Finally, we consider the opportunities and drawbacks of intensively interrogating antibodies isolated from HIV-infected individuals to guide strategies aimed at developing effective antibody-based vaccine and therapeutic interventions for HIV. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

  9. A Mathematical Model of Baculovirus Infection on Insect Cells at Low Multiplicity of Infection

    Institute of Scientific and Technical Information of China (English)

    You-Hong ZHANG; Josée C. MERCHUK

    2004-01-01

    The expression efficiency of the insect cells-baculovirus system used for insecticidal virus production and the expression of medically useful foreign genes is closely related with the dynamics of infection. The present studies develop a model of the dynamic process of insect cell infection with baculovirus at low multiplicity of infection (MOI), which is based on the multi-infection cycles of insect cell infection at low MOI. A mathematical model for the amount of viruses released from primary infected cells and the amount of free viruses before secondary infected cells release viruses has been developed. Comparison of the simulation results with the experimental data confirms qualitatively that this model is highly reasonable before secondary infected cells release viruses. This model is considered as a base for further modeling the entire complicated infection process.

  10. Bacterial foodborne infections after hematopoietic cell transplantation.

    Science.gov (United States)

    Boyle, Nicole M; Podczervinski, Sara; Jordan, Kim; Stednick, Zach; Butler-Wu, Susan; McMillen, Kerry; Pergam, Steven A

    2014-11-01

    Diarrhea, abdominal pain, and fever are common among patients undergoing hematopoietic cell transplantation (HCT), but such symptoms are also typical with foodborne infections. The burden of disease caused by foodborne infections in patients undergoing HCT is unknown. We sought to describe bacterial foodborne infection incidence after transplantation within a single-center population of HCT recipients. All HCT recipients who underwent transplantation from 2001 through 2011 at the Fred Hutchinson Cancer Research Center in Seattle, Washington were followed for 1 year after transplantation. Data were collected retrospectively using center databases, which include information from transplantation, on-site examinations, outside records, and collected laboratory data. Patients were considered to have a bacterial foodborne infection if Campylobacter jejuni/coli, Listeria monocytogenes, E. coli O157:H7, Salmonella species, Shigella species, Vibrio species, or Yersinia species were isolated in culture within 1 year after transplantation. Nonfoodborne infections with these agents and patients with pre-existing bacterial foodborne infection (within 30 days of transplantation) were excluded from analyses. A total of 12 of 4069 (.3%) patients developed a bacterial foodborne infection within 1 year after transplantation. Patients with infections had a median age at transplantation of 50.5 years (interquartile range [IQR], 35 to 57), and the majority were adults ≥18 years of age (9 of 12 [75%]), male gender (8 of 12 [67%]) and had allogeneic transplantation (8 of 12 [67%]). Infectious episodes occurred at an incidence rate of 1.0 per 100,000 patient-days (95% confidence interval, .5 to 1.7) and at a median of 50.5 days after transplantation (IQR, 26 to 58.5). The most frequent pathogen detected was C. jejuni/coli (5 of 12 [42%]) followed by Yersinia (3 of 12 [25%]), although Salmonella (2 of 12 [17%]) and Listeria (2 of 12 [17%]) showed equal frequencies; no cases of Shigella

  11. PARASITIC INFECTIONS IN HEMATOPOIETIC STEM CELL TRANSPLANTATION

    Directory of Open Access Journals (Sweden)

    Isidro Jarque

    2016-07-01

    Full Text Available Parasitic infections are rarely documented in hematopoietic stem cell transplant recipients. However, they may be responsible for fatal complications that are only diagnosed at autopsy. Increased awareness of the possibility of parasitic diseases both in autologous and allogeneic stem cell transplant patients is relevant not only for implementing preventive measures but also for performing an early diagnosis and starting appropriate therapy for these unrecognized but fatal infectious complications in hematopoietic transplant recipients. In this review, we will focus on parasitic diseases occurring in this population especially those with major clinical relevance including toxoplasmosis, American trypanosomiasis, leishmaniasis, malaria, and strongyloidiasis, among others, highlighting the diagnosis and management in hematopoietic transplant recipients.

  12. Mesenchymal Stromal Cells and Viral Infection

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    Maytawan Thanunchai

    2015-01-01

    Full Text Available Mesenchymal Stromal Cells (MSCs are a subset of nonhematopoietic adult stem cells, readily isolated from various tissues and easily culture-expanded ex vivo. Intensive studies of the immune modulation and tissue regeneration over the past few years have demonstrated the great potential of MSCs for the prevention and treatment of steroid-resistant acute graft-versus-host disease (GvHD, immune-related disorders, and viral diseases. In immunocompromised individuals, the immunomodulatory activities of MSCs have raised safety concerns regarding the greater risk of primary viral infection and viral reactivation, which is a major cause of mortality after allogeneic transplantation. Moreover, high susceptibilities of MSCs to viral infections in vitro could reflect the destructive outcomes that might impair the clinical efficacy of MSCs infusion. However, the interplay between MSCs and virus is like a double-edge sword, and it also provides beneficial effects such as allowing the proliferation and function of antiviral specific effector cells instead of suppressing them, serving as an ideal tool for study of viral pathogenesis, and protecting hosts against viral challenge by using the antimicrobial activity. Here, we therefore review favorable and unfavorable consequences of MSCs and virus interaction with the highlight of safety and efficacy for applying MSCs as cell therapy.

  13. Quantitative-PCR Assessment of Cryptosporidium parvum Cell Culture Infection

    OpenAIRE

    Di Giovanni, George D.; LeChevallier, Mark W.

    2005-01-01

    A quantitative TaqMan PCR method was developed for assessing the Cryptosporidium parvum infection of in vitro cultivated human ileocecal adenocarcinoma (HCT-8) cell cultures. This method, termed cell culture quantitative sequence detection (CC-QSD), has numerous applications, several of which are presented. CC-QSD was used to investigate parasite infection in cell culture over time, the effects of oocyst treatment on infectivity and infectivity assessment of different C. parvum isolates. CC-Q...

  14. Growth in agarose of human cells infected with cytomegalovirus.

    Science.gov (United States)

    Lang, D J; Montagnier, L; Latarjet, R

    1974-08-01

    After infection by human cytomegalovirus (CMV), human diploid fibroblasts could grow in agarose medium for several generations. Clones of infected cells grew for weeks, although in every case they ultimately underwent lysis owing to the cytopathic effect of the virus. Virus was inoculated at high dilution and after UV irradiation in an effort to derive cells infected with noninfectious defective particles still capable of inducing cell stimulation. Dilute or irradiated virus occasionally yielded large colonies of replicating cells, although permanent transformation was not observed. One clone derived from UV-CMV-infected cells was passaged four times before undergoing lysis. During these passages the cells exhibited alterations in morphology and orientation.

  15. CD8+ T cells in Leishmania infections: friends or foes?

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    Simona eStager

    2012-01-01

    Full Text Available Host protection against several intracellular pathogens requires the induction of CD8+ T cell responses. CD8+ T cells are potent effector cells that can produce high amounts of pro-inflammatory cytokines and kill infected target cells efficiently. However, a protective role for CD8+ T cells during Leishmania infections is still controversial and largely depends on the infection model. In this review, we discuss the role of CD8+ T cells during various types Leishmania infections, following vaccination, and as potential immunotherapeutic targets.

  16. Interferon Response in Hepatitis C Virus (HCV) Infection: Lessons from Cell Culture Systems of HCV Infection.

    Science.gov (United States)

    Sung, Pil Soo; Shin, Eui-Cheol; Yoon, Seung Kew

    2015-01-01

    Hepatitis C virus (HCV) is a positive-stranded RNA virus that infects approximately 130-170 million people worldwide. In 2005, the first HCV infection system in cell culture was established using clone JFH-1, which was isolated from a Japanese patient with fulminant HCV infection. JFH-1 replicates efficiently in hepatoma cells and infectious virion particles are released into the culture supernatant. The development of cell culture-derived HCV (HCVcc) systems has allowed us to understand how hosts respond to HCV infection and how HCV evades host responses. Although the mechanisms underlying the different outcomes of HCV infection are not fully understood, innate immune responses seem to have a critical impact on the outcome of HCV infection, as demonstrated by the prognostic value of IFN-λ gene polymorphisms among patients with chronic HCV infection. Herein, we review recent research on interferon response in HCV infection, particularly studies using HCVcc infection systems.

  17. Risk of Abnormal Red Blood Cell to Get Malarial Infection

    OpenAIRE

    Viroj Wiwanitkit

    2008-01-01

    Malarial infection in red blood cell disorder is an interesting topic in tropical medicine. In this work, the author proposes a new idea on the physical property of red blood cell and risk for getting malarial infection. The study on scenario of red blood cell disorders is performed. Conclusively, the author found that physical property of red blood cell is an important determinant for getting malarial infection

  18. Modeling malaria infected cells in microcirculation

    Science.gov (United States)

    Raffiee, Amir Hossein; Dabiri, Sadegh; Motavalizadeh Ardekani, Arezoo

    2016-11-01

    Plasmodim (P.) falciparum is one of the deadliest types of malaria species that invades healthy red blood cells (RBC) in human blood flow. This parasite develops through 48-hour intra-RBC process leading to significant morphological and mechanical (e.g., stiffening) changes in RBC membrane. These changes have remarkable effects on blood circulation such as increase in flow resistance and obstruction in microcirculation. In this work a computational framework is developed to model RBC suspension in blood flow using front-tracking technique. The present study focuses on blood flow behavior under normal and infected circumstances and predicts changes in blood rheology for different levels of parasitemia and hematocrit. This model allows better understanding of blood flow circulation up to a single cell level and provides us with realistic and deep insight into hematologic diseases such as malaria.

  19. Susceptibility of different leukocyte cell types to Vaccinia virus infection

    Directory of Open Access Journals (Sweden)

    Sánchez-Puig Juana M

    2004-11-01

    Full Text Available Abstract Background Vaccinia virus, the prototype member of the family Poxviridae, was used extensively in the past as the Smallpox vaccine, and is currently considered as a candidate vector for new recombinant vaccines. Vaccinia virus has a wide host range, and is known to infect cultures of a variety of cell lines of mammalian origin. However, little is known about the virus tropism in human leukocyte populations. We report here that various cell types within leukocyte populations have widely different susceptibility to infection with vaccinia virus. Results We have investigated the ability of vaccinia virus to infect human PBLs by using virus recombinants expressing green fluorescent protein (GFP, and monoclonal antibodies specific for PBL subpopulations. Flow cytometry allowed the identification of infected cells within the PBL mixture 1–5 hours after infection. Antibody labeling revealed that different cell populations had very different infection rates. Monocytes showed the highest percentage of infected cells, followed by B lymphocytes and NK cells. In contrast to those cell types, the rate of infection of T lymphocytes was low. Comparison of vaccinia virus strains WR and MVA showed that both strains infected efficiently the monocyte population, although producing different expression levels. Our results suggest that MVA was less efficient than WR in infecting NK cells and B lymphocytes. Overall, both WR and MVA consistently showed a strong preference for the infection of non-T cells. Conclusions When infecting fresh human PBL preparations, vaccinia virus showed a strong bias towards the infection of monocytes, followed by B lymphocytes and NK cells. In contrast, very poor infection of T lymphocytes was detected. These finding may have important implications both in our understanding of poxvirus pathogenesis and in the development of improved smallpox vaccines.

  20. Infection of Dendritic Cells by the Maedi-Visna Lentivirus

    OpenAIRE

    Ryan, Susanna; Tiley, Laurence; McConnell, Ian; Blacklaws, Barbara

    2000-01-01

    The early stages of lentivirus infection of dendritic cells have been studied in an in vivo model. Maedi-visna virus (MVV) is a natural pathogen of sheep with a tropism for macrophages, but the infection of dendritic cells has not been proven, largely because of the difficulties of definitively distinguishing the two cell types. Afferent lymphatic dendritic cells from sheep have been phenotypically characterized and separated from macrophages. Dendritic cells purified from experimentally infe...

  1. Polypeptide synthesis in alphavirus-infected Aedes albopictus cells during the establishment of persistent infection.

    Science.gov (United States)

    Richardson, M A; Boulton, R W; Raghow, R S; Dalgarno, L

    1980-01-01

    Polypeptide synthesis was examined in mosquito cells during the establishment of a persistent infection with two alphaviruses, Ross River virus (RRV) and Semliki Forest virus (SFV), and in vertebrate cells cytopathically-infected with the same viruses. In Aedes albopictus cell, RRV reached peak titres at 34--48 hours p.i. At 12 hours 85 per cent of cells assayed as infected by infective centre assay; by 48 hours when persistence was established, virus production was reduced and less than 5 per cent of cells assayed as infected. There was no shut-down of host polypeptide synthesis during infection. Viral polypeptide synthesis was maximal between 10 and 24 hours p.i. The major viral polypeptides labelled were nucleocapsid protein and envelope protein(s). The precursor polypeptide p95 which was prominent in infected BHK cells was not detected in mosquito cells. Similar results were obtained on SFV infection. During the establishment of persistence there was a coordinate decline in the synthesis of RRV polypeptides, reaching undetectable levels by 72 hours p.i. Subculturing persitently-infected cells led to a small increase in viral polypeptide synthesis and virus titre. In contrast, during RRV growth in BHK celos host protein synthesis was severly inhibited and by 9--11 hours p.i. virus-specific polypeptide synthesis represented more than 90 per cent of total protein synthetic activity.

  2. Active Epstein-Barr virus infection after allogeneic stem cell transplantation : re-infection or reactivation?

    NARCIS (Netherlands)

    Meijer, E; Spijkers, S; Moschatsis, S; Boland, GJ; Thijsen, SFT; van Loon, AM; Verdonck, LF

    2005-01-01

    Recipients of allogeneic stem cell transplants (SCT) often show active Epstein-Barr virus (EBV) infection, which may progress to EBV-associated lymphoproliferative disorders. It is not known whether these EBV infections are true reactivations of the endogenous EBV strain or re-infections with an exo

  3. Transient Oral Human Cytomegalovirus Infections Indicate Inefficient Viral Spread from Very Few Initially Infected Cells.

    Science.gov (United States)

    Mayer, Bryan T; Krantz, Elizabeth M; Swan, David; Ferrenberg, James; Simmons, Karen; Selke, Stacy; Huang, Meei-Li; Casper, Corey; Corey, Lawrence; Wald, Anna; Schiffer, Joshua T; Gantt, Soren

    2017-06-15

    Cytomegalovirus (CMV) is acquired by the oral route in children, and primary infection is associated with abundant mucosal replication, as well as the establishment of latency in myeloid cells that results in lifelong infection. The efficiency of primary CMV infection in humans following oral exposure, however, is unknown. We consistently detected self-limited, low-level oral CMV shedding events, which we termed transient CMV infections, in a prospective birth cohort of 30 highly exposed CMV-uninfected infants. We estimated the likelihood of transient oral CMV infections by comparing their observed frequency to that of established primary infections, characterized by persistent high-level shedding, viremia, and seroconversion. We developed mathematical models of viral dynamics upon initial oral CMV infection and validated them using clinical shedding data. Transient infections comprised 76 to 88% of oral CMV shedding events. For this high percentage of transient infections to occur, we identified two mathematical prerequisites: a very small number of initially infected oral cells (1 to 4) and low viral infectivity (<1.5 new cells infected/cell). These observations indicate that oral CMV infection in infants typically begins with a single virus that spreads inefficiently to neighboring cells. Thus, although the incidence of CMV infection is high during infancy, our data provide a mechanistic framework to explain why multiple CMV exposures are typically required before infection is successfully established. These findings imply that a sufficiently primed immune response could prevent CMV from establishing latent infection in humans and support the achievability of a prophylactic CMV vaccine.IMPORTANCE CMV infects the majority of the world's population and is a major cause of birth defects. Developing a vaccine to prevent CMV infection would be extremely valuable but would be facilitated by a better understanding of how natural human CMV infection is acquired. We

  4. Brucella abortus-infected B cells induce osteoclastogenesis.

    Science.gov (United States)

    Pesce Viglietti, Ayelén Ivana; Arriola Benitez, Paula Constanza; Giambartolomei, Guillermo Hernán; Delpino, María Victoria

    2016-09-01

    Brucella abortus is an intracellular bacterium that establishes lifelong infections in livestock and humans although the mechanisms of its chronicity are poorly understood. Activated B cells have long lifespan and B. abortus infection activates B cells. Our results indicate that the direct infection of B cells with B. abortus induced matrix metalloproteinase-9 (MMP-9), receptor activator for NF κB ligand (RANKL), tumor necrosis factor (TNF)-α and interleukin (IL)-6 secretion. In addition, supernatants from B. abortus-infected B cells induced bone marrow-derived monocytes to undergo osteoclastogenesis. Using osteoprotegerin, RANKL's decoy receptor, we determined that RANKL is involved in osteoclastogenesis induced by supernatants from B. abortus-infected B cells. The results presented here shed light on how the interactions of B. abortus with B cells may have a role in the pathogenesis of brucellar osteoarticular disease.

  5. Natural killer cells in hepatitis B virus infection.

    Science.gov (United States)

    Wu, Shao-fei; Wang, Wen-jing; Gao, Yue-qiu

    2015-01-01

    Natural killer cells are a unique type of lymphocytes with cytotoxic capacity, and play important roles against tumors and infections. Recently, natural killer cells have been increasingly valued in their effects in hepatitis B virus infection. Since hepatitis B virus is not cytopathic, the subsequent antiviral immune responses of the host are responsible for sustaining the liver injury, which may result in cirrhosis and even hepatocellular carcinoma. Many studies have confirmed that natural killer cells participate in anti-hepatitis B virus responses both in the early phase after infection and in the chronic phase via cytolysis, degranulation, and cytokine secretion. However, natural killer cells play dichotomic roles: they exert antiviral and immunoregulatory functions whilst contribute to the pathogenesis of liver injury. Here, we review the roles of natural killer cells in hepatitis B virus infection, introducing novel therapeutic strategies for controlling hepatitis B virus infection via the modulation of natural killer cells. Copyright © 2015 Elsevier Editora Ltda. All rights reserved.

  6. Modulation of host-cell MAPkinase signaling during fungal infection

    OpenAIRE

    2015-01-01

    Fungal infections contribute substantially to human suffering and mortality. The interaction between fungal pathogens and their host involves the invasion and penetration of the surface epithelium, activation of cells of the innate immune system and the generation of an effective response to block infection. Numerous host-cell signaling pathways are activated during fungal infection. This review will focus on the main fungal pathogens Aspergillus fumigatus, Candida albicans and Cryptococcus n...

  7. Extracellular vesicles from infected cells: potential for direct pathogenesis

    Directory of Open Access Journals (Sweden)

    Angela M Schwab

    2015-10-01

    Full Text Available Infections that result in natural or manmade spread of lethal biological agents are a concern and require national and focused preparedness. In this manuscript, as part of an early diagnostics and pathogen treatment strategy, we have focused on extracellular vesicles (EVs that arise following infections. Although the field of biodefense does not currently have a rich resource in EVs literature, none the less, similar pathogens belonging to the more classical emerging and non-emerging diseases have been studied in their EV/exosomal contents and function. These exosomes are formed in late endosomes and released from the cell membrane in almost every cell type in vivo. These vesicles contain proteins, RNA, and lipids from the cells they originate from and function in development, signal transduction, cell survival, and transfer of infectious material. The current review focuses on how different forms of infection exploit the exosomal pathway and how exosomes can be exploited artificially to treat infection and disease and potentially also be used as a source of vaccine. Virally-infected cells can secrete viral as well as cellular proteins and RNA in exosomes, allowing viruses to cause latent infection and spread of miRNA to nearby cells prior to a subsequent infection. In addition to virally-infected host cells, bacteria, protozoa, and fungi can all release small vesicles that contain Pathogen-Associated Molecular Patterns (PAMPs, regulating the neighboring uninfected cells. Examples of exosomes from both virally and bacterially infected cells point toward a re-programming network of pathways in the recipient cells. Finally, many of these exosomes contain cytokines and miRNAs that in turn can effect gene expression in the recipient cells through the classical TLR and NFkB pathway. Therefore, although exosomes do not replicate as an independent entity, they however facilitate movement of infectious material through tissues and may be the cause of

  8. The cell biology of cryptosporidium infection.

    Science.gov (United States)

    O'Hara, Steven P; Chen, Xian-Ming

    2011-08-01

    Cryptosporidiosis remains a significant cause of enteric disease worldwide. Basic investigations of host: pathogen interactions have revealed the intricate processes mediating infection. The following summarizes the interactions that mediate infection and the host responses that both permit and ultimately clear the infection.

  9. Suppression of HIV-1 Infectivity by Human Glioma Cells.

    Science.gov (United States)

    Hoque, Sheikh Ariful; Tanaka, Atsushi; Islam, Salequl; Ahsan, Gias Uddin; Jinno-Oue, Atsushi; Hoshino, Hiroo

    2016-05-01

    HIV-1 infection to the central nervous system (CNS) is very common in AIDS patients. The predominant cell types infected in the brain are monocytes and macrophages, which are surrounded by several HIV-1-resistant cell types, such as astrocytes, oligodendrocytes, neurons, and microvascular cells. The effect of these HIV-1-resistant cells on HIV-1 infection is largely unknown. In this study, we examined the stability of HIV-1 cultured with several human glioblastoma cell lines, for example, NP-2, U87MG, T98G, and A172, to determine whether these HIV-1-resistant brain cells could enhance or suppress HIV-1 infection and thus modulate HIV-1 infection in the CNS. The HIV-1 titer was determined using the MAGIC-5A indicator cell line as well as naturally occurring CD4(+) T cells. We found that the stability of HIV-1 incubated with NP-2 or U87MG cells at 37°C was significantly shorter (half-life, 2.5-4 h) compared to that of HIV-1 incubated with T98G or A172 cells or in culture medium without cells (half-life, 8-18 h). The spent culture media (SCM) of NP-2 and U87MG cells had the ability to suppress both R5- and X4-HIV-1 infection by inhibiting HIV-1 attachment to target cells. This inhibitory effect was eliminated by the treatment of the SCM with chondroitinase ABC but not heparinase, suggesting that the inhibitory factor(s) secreted by NP-2 and U87MG cells was chiefly mediated by chondroitin sulfate (CS) or CS-like moiety. Thus, this study reveals that some but not all glioma cells secrete inhibitory molecules to HIV-1 infection that may contribute in lowering HIV-1 infection in the CNS in vivo.

  10. Intracellular Events and Cell Fate in Filovirus Infection

    Directory of Open Access Journals (Sweden)

    Elena Ryabchikova

    2011-08-01

    Full Text Available Marburg and Ebola viruses cause a severe hemorrhagic disease in humans with high fatality rates. Early target cells of filoviruses are monocytes, macrophages, and dendritic cells. The infection spreads to the liver, spleen and later other organs by blood and lymph flow. A hallmark of filovirus infection is the depletion of non-infected lymphocytes; however, the molecular mechanisms leading to the observed bystander lymphocyte apoptosis are poorly understood. Also, there is limited knowledge about the fate of infected cells in filovirus disease. In this review we will explore what is known about the intracellular events leading to virus amplification and cell damage in filovirus infection. Furthermore, we will discuss how cellular dysfunction and cell death may correlate with disease pathogenesis.

  11. Persistent, triple-virus co-infections in mosquito cells

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    Malasit Prida

    2010-01-01

    Full Text Available Abstract Background It is known that insects and crustaceans can carry simultaneous, active infections of two or more viruses without showing signs of disease, but it was not clear whether co-infecting viruses occupied the same cells or different cells in common target tissues. Our previous work showed that successive challenge of mosquito cell cultures followed by serial, split-passage resulted in stabilized cultures with 100% of the cells co-infected with Dengue virus (DEN and an insect parvovirus (densovirus (DNV. By addition of Japanese encephalitis virus (JE, we tested our hypothesis that stable, persistent, triple-virus co-infections could be obtained by the same process. Results Using immunocytochemistry by confocal microscopy, we found that JE super-challenge of cells dually infected with DEN and DNV resulted in stable cultures without signs of cytopathology, and with 99% of the cells producing antigens of the 3 viruses. Location of antigens for all 3 viruses in the triple co-infections was dominant in the cell nuclei. Except for DNV, this differed from the distribution in cells persistently infected with the individual viruses or co-infected with DNV and DEN. The dependence of viral antigen distribution on single infection or co-infection status suggested that host cells underwent an adaptive process to accommodate 2 or more viruses. Conclusions Individual mosquito cells can accommodate at least 3 viruses simultaneously in an adaptive manner. The phenomenon provides an opportunity for genetic exchange between diverse viruses and it may have important medical and veterinary implications for arboviruses.

  12. Activation mechanisms of natural killer cells during influenza virus infection.

    Directory of Open Access Journals (Sweden)

    Ilwoong Hwang

    Full Text Available During early viral infection, activation of natural killer (NK cells elicits the effector functions of target cell lysis and cytokine production. However, the cellular and molecular mechanisms leading to NK cell activation during viral infections are incompletely understood. In this study, using a model of acute viral infection, we investigated the mechanisms controlling cytotoxic activity and cytokine production in response to influenza (flu virus. Analysis of cytokine receptor deficient mice demonstrated that type I interferons (IFNs, but not IL-12 or IL-18, were critical for the NK cell expression of both IFN-γ and granzyme B in response to flu infection. Further, adoptive transfer experiments revealed that NK cell activation was mediated by type I IFNs acting directly on NK cells. Analysis of signal transduction molecules showed that during flu infection, STAT1 activation in NK cells was completely dependent on direct type I IFN signaling, whereas STAT4 activation was only partially dependent. In addition, granzyme B induction in NK cells was mediated by signaling primarily through STAT1, but not STAT4, while IFN-γ production was mediated by signaling through STAT4, but not STAT1. Therefore, our findings demonstrate the importance of direct action of type I IFNs on NK cells to mount effective NK cell responses in the context of flu infection and delineate NK cell signaling pathways responsible for controlling cytotoxic activity and cytokine production.

  13. [Modulation of inflammatory cells in helminth infections].

    Science.gov (United States)

    Bruschi, F

    1997-01-01

    In this review, different mechanisms by which helminthic parasites modulate the activities of inflammatory cells are considered. Examples are presented of parasitic products interfering with lymphocytes and their products such as antibodies, then modifying both regulation and effector response of the immune system. Furthermore, examples of interference on the complement system are illustrated. Parasites such as Ancylostoma caninum produce factors such as the neutrophil inhibitory factor (NIF) capable of inhibiting the neutrophil-endothelium adhesion, whereas Trichinella spiralis produces a glycoprotein, the 45gp, which inhibits different neutrophil functions. Parasites are also able to modulate the function of the monocytes-macrophages which in some infections play a crucial role; the modulation of NO synthesis is also relevant to the host-parasite relationship. Finally, the different anti-oxidant systems of helminthic parasites are described. The comprehension of such evasion mechanisms of the immune response is necessary to develop vaccines and new drugs, but it is also useful to clarify the contribution of parasites to immune system evolution.

  14. Growth in Agarose of Human Cells Infected with Cytomegalovirus

    Science.gov (United States)

    Lang, David J.; Montagnier, Luc; Latarjet, Raymond

    1974-01-01

    After infection by human cytomegalovirus (CMV), human diploid fibroblasts could grow in agarose medium for several generations. Clones of infected cells grew for weeks, although in every case they ultimately underwent lysis owing to the cytopathic effect of the virus. Virus was inoculated at high dilution and after UV irradiation in an effort to derive cells infected with noninfectious defective particles still capable of inducing cell stimulation. Dilute or irradiated virus occasionally yielded large colonies of replicating cells, although permanent transformation was not observed. One clone derived from UV-CMV-infected cells was passaged four times before undergoing lysis. During these passages the cells exhibited alterations in morphology and orientation. Images PMID:4367907

  15. Late steps of parvoviral infection induce changes in cell morphology.

    Science.gov (United States)

    Pakkanen, Kirsi; Nykky, Jonna; Vuento, Matti

    2008-11-01

    Previously, virus-induced non-filopodial extensions have not been encountered in connection with viral infections. Here, we report emergence of long extensions protruding from Norden laboratory feline kidney (NLFK) and A72 (canine fibroma) cells infected with canine parvovirus for 72 h. These extensions significantly differ in length and number from those appearing in control cells. The most striking feature in the extensions is the length, reaching up to 130 microm, almost twice the average length of a healthy NLFK cell. In A72 cells, the extensions were even longer, up to 200 microm. The results presented here also suggest that the events leading to the growth of these extensions start earlier in infection and abnormal extension growth is detectable already at 24-h post-infection (p.i.). These extensions may have a vital role in the cell-to-cell transmission of the virus.

  16. Combination of anti-retroviral drugs and radioimmunotherapy specifically kills infected cells from HIV infected individuals

    Directory of Open Access Journals (Sweden)

    Dina Tsukrov

    2016-09-01

    Full Text Available Eliminating virally infected cells is an essential component of any HIV eradication strategy. Radioimmunotherapy (RIT, a clinically established method for killing cells using radiolabeled antibodies, was recently applied to target HIV-1 gp41 antigen expressed on the surface of infect-ed cells. Since gp41 expression by infected cells is likely down-regulated in patients on an-tiretroviral therapy (ART, we evaluated the ability of RIT to kill ART-treated infected cells us-ing both in vitro models and lymphocytes isolated from HIV-infected subjects. Human peripheral blood mononuclear cells (PBMCs were infected with HIV and cultured in the presence of two clinically relevant ART combinations. Scatchard analysis of the 2556 human monoclonal anti-body to HIV gp41 binding to the infected and ART-treated cells demonstrated sufficient residual expression of gp41 on the cell surface to warrant subsequent RIT. This is the first time the quantification of gp41 post-ART is being reported. Cells were then treated with Bismuth-213-labeled 2556 antibody. conjugated to the human monoclonal antibody 2556, which binds to HIV gp41. Cell survival was quantified by Trypan blue and residual viremia by p24 ELISA. Cell surface gp41 expression was assessed by Scatchard analysis. The experiments were repeated using PBMCs isolated from blood specimens obtained from 15 HIV-infected individuals: ten on ART and five ART-naive. We found that 213Bi-2556 killed ART-treated infected PBMCs and reduced viral production to undetectable levels. ART and RIT co-treatment was more effective at reducing viral load in vitro than either therapy alone, indicating that gp41 expression under ART was sufficient to allow 213Bi-2556 to deliver cytocidal doses of radiation to infected cells. This study provides proof of concept that 213Bi-2556 may represent an innovative and effective targeting method for killing HIV-infected cells treated with ART, and supports continued development of 213Bi

  17. The homeostasis of Plasmodium falciparum-infected red blood cells.

    Directory of Open Access Journals (Sweden)

    Jakob M A Mauritz

    2009-04-01

    Full Text Available The asexual reproduction cycle of Plasmodium falciparum, the parasite responsible for severe malaria, occurs within red blood cells. A merozoite invades a red cell in the circulation, develops and multiplies, and after about 48 hours ruptures the host cell, releasing 15-32 merozoites ready to invade new red blood cells. During this cycle, the parasite increases the host cell permeability so much that when similar permeabilization was simulated on uninfected red cells, lysis occurred before approximately 48 h. So how could infected cells, with a growing parasite inside, prevent lysis before the parasite has completed its developmental cycle? A mathematical model of the homeostasis of infected red cells suggested that it is the wasteful consumption of host cell hemoglobin that prevents early lysis by the progressive reduction in the colloid-osmotic pressure within the host (the colloid-osmotic hypothesis. However, two critical model predictions, that infected cells would swell to near prelytic sphericity and that the hemoglobin concentration would become progressively reduced, remained controversial. In this paper, we are able for the first time to correlate model predictions with recent experimental data in the literature and explore the fine details of the homeostasis of infected red blood cells during five model-defined periods of parasite development. The conclusions suggest that infected red cells do reach proximity to lytic rupture regardless of their actual volume, thus requiring a progressive reduction in their hemoglobin concentration to prevent premature lysis.

  18. Methamphetamine Enhances HIV-1 Infectivity in Monocyte Derived Dendritic Cells

    OpenAIRE

    2008-01-01

    The US is currently experiencing an epidemic of methamphetamine (Meth) use as a recreational drug. Recent studies also show a high prevalence of HIV-1 infection among Meth users. We report that Meth enhances HIV-1 infectivity of dendritic cells as measured by multinuclear activation of a galactosidase indicator (MAGI) cell assay, p24 assay, and LTR-RU5 amplification. Meth induces increased HIV-1 infection in association with an increase in the HIV-1 coreceptors, CXCR4 and CCR5, and infection ...

  19. HCMV Infection Depress NGF Expression in Human Glioma Cells

    Institute of Scientific and Technical Information of China (English)

    Hai-tao WANG; Bin WANG; Zhi-jun LIU; Zhi-qiang BAI; Ling LI; Dong-meng QIAN; Zhi-yong YAN; Xu-xia SONG

    2009-01-01

    Human cytomegalovirus (HCMV) is the most common cause of congenital infection, resulting in birth defects such as microcephaly. In this study, RT-PCR and Western Blotting were performed to quantify the regulation of endogenic nerve growth factor expression in neuroglia cells by HCMV infection. The results showed that basal, endogenous NGF expression in U251 was unchanged during early HCMV infection. NGF expression is strongly down-regulated during the latent phase of infection. These results suggest that HCMV can depress the NGF expression in U251 cells.

  20. Immune regulation in Chandipura virus infection: characterization of CD4+ T regulatory cells from infected mice

    Directory of Open Access Journals (Sweden)

    Shahir Prajakta

    2011-05-01

    Full Text Available Abstract Back ground Chandipura virus produces acute infection in mice. During infection drastic reduction of CD4+, CD8+ and CD19 + cell was noticed. Depletion of lymphocytes also noticed in spleen. The reduction may be due to the regulatory mechanism of immune system to prevent the bystander host tissue injury. There are several mechanisms like generation of regulatory cells, activation induced cell death (ACID etc were indicated to control the activation and maintain cellular homeostasis. Role of regulatory cells in homeostasis has been described in several viral diseases. This study was undertaken to characterize CD4+T regulatory cells from the infected mice. Method In this study we purified the CD4+ T cells from Chandipura virus infected susceptible Balb/c mice. CD4+ T regulatory cells were identified by expression of cell surface markers CD25, CD127 and CTLA-4 and intracellular markers Foxp3, IL-10 and TGF-beta. Antigen specificity and ability to suppress the proliferation of other lymphocytes were studied in vitro by purified CD4+CD25+T regulatory cells from infected mice. The proliferation was calculated by proliferation module of Flow Jo software. Expression of death receptors on regulatory cells were studied by flowcytometer. Results The CD4+ T cells isolated from infected mice expressed characteristic markers of regulatory phenotype at all post infective hours tested. The CD4+ T regulatory cells were proliferated when stimulated with Chandipura virus antigen. The regulatory cells did not suppress the proliferation of splenocytes stimulated with anti CD3 antibody when co cultured with them. Interesting observation was, while purification of CD4+ T cells by negative selection, the population of cells negative for CD4 also co purified along with CD4+ T cell. Flow cytometry analysis and light microscopy revealed that CD4 negative cells were of different size and shape (atypical compared to the normal lymphocytes. Greater percentage of

  1. Multi-peak Phenomenon of Insect Cell Infection with Baculovirus at Low Multiplicity of Infection

    Institute of Scientific and Technical Information of China (English)

    You-Hong ZHANG

    2005-01-01

    In this communication we report the infection of armyworm Spodoptera frugiperda IPLB-Sf21 cells with Anticarsia gemmatalis multicapsid nucleopolyhedrovirus at low multiplicity of infection (MOI).The temporal variation of the extra-cellular virus and of the unstained cell was followed. The series of peaks in the virus concentration and the unstained cells count were used in order to infer the dynamic mechanism of the infection at low MOI. This mechanism can be used as the basis for the future formulation of a mathematical model of the process.

  2. Cytomegalovirus-Infected Cells Resist T Cell Mediated Killing in an HLA-Recognition Independent Manner.

    Science.gov (United States)

    Proff, Julia; Walterskirchen, Christian; Brey, Charlotte; Geyeregger, Rene; Full, Florian; Ensser, Armin; Lehner, Manfred; Holter, Wolfgang

    2016-01-01

    In order to explore the potential of HLA-independent T cell therapy for human cytomegalovirus (HCMV) infections, we developed a chimeric antigen receptor (CAR) directed against the HCMV encoded glycoprotein B (gB), which is expressed at high levels on the surface of infected cells. T cells engineered with this anti-gB CAR recognized HCMV-infected cells and released cytokines and cytotoxic granules. Unexpectedly, and in contrast to analogous approaches for HIV, Hepatitis B or Hepatitis C virus, we found that HCMV-infected cells were resistant to killing by the CAR-modified T cells. In order to elucidate whether this phenomenon was restricted to the use of CARs, we extended our experiments to T cell receptor (TCR)-mediated recognition of infected cells. To this end we infected fibroblasts with HCMV-strains deficient in viral inhibitors of antigenic peptide presentation and targeted these HLA-class I expressing peptide-loaded infected cells with peptide-specific cytotoxic T cells (CTLs). Despite strong degranulation and cytokine production by the T cells, we again found significant inhibition of lysis of HCMV-infected cells. Impairment of cell lysis became detectable 1 day after HCMV infection and gradually increased during the following 3 days. We thus postulate that viral anti-apoptotic factors, known to inhibit suicide of infected host cells, have evolved additional functions to directly abrogate T cell cytotoxicity. In line with this hypothesis, CAR-T cell cytotoxicity was strongly inhibited in non-infected fibroblasts by expression of the HCMV-protein UL37x1, and even more so by additional expression of UL36. Our data extend the current knowledge on Betaherpesviral evasion from T cell immunity and show for the first time that, beyond impaired antigen presentation, infected cells are efficiently protected by direct blockade of cytotoxic effector functions through viral proteins.

  3. Cell-mediated infection of cervix derived epithelial cells with primary isolates of human immunodeficiency virus.

    Science.gov (United States)

    Tan, X; Phillips, D M

    1996-01-01

    We have previously demonstrated that HIV-infected transformed T-cells or monocytes adhere to monolayers of CD4-negative epithelial cells. Adhesion is soon followed by budding of HIV from infected mononuclear cells onto the surface of epithelial cells. Epithelial cells subsequently take up virus and become productively infected. Based on these findings, we proposed that sexual transmission of HIV may involve cell-mediated infection of intact mucosal epithelia of the urogenital tract. However, it has become increasingly clear that primary cells and HIV strains isolated from patients are more appropriate models for HIV infection than established cell lines and lab strains of virus. In the studies described here, we infected cervix-derived epithelial monolayers with primary monocytes infected with patient isolates of non-syncytial inducing (NSI) macrophage-tropic strains of HIV. Under the culture conditions employed, HIV-infected primary monocytes do not remain adherent to the apical surface of the epithelium, as did HIV-infected transformed cells. Instead, following adherence, the primary cells migrate between epithelial cells. Virus is secreted from a pseudopod as HIV-infected primary monocytes pass between cells of the epithelium. Productive infection of the epithelium was detected by p24 ELISA and PCR Southern blot analysis. Infection can be blocked by sera from HIV-seropositive individuals or by certain sulfated polysaccharides. These findings support the supposition that transmission of HIV may occur via cell-mediated infection of intact epithelia. The observations also hint at the possibility that-HIV-infected monocyte/macrophages in semen or cervical-vaginal secretions could cross intact epithelia by passing between epithelial cells. Blocking studies suggest that it may be possible to inhibit sexual transmission of HIV either by antibodies in genital tract secretions or by a topical formulation containing certain sulfated polysaccharides.

  4. Dendritic Cells and HIV-1 Trans-Infection

    Directory of Open Access Journals (Sweden)

    David McDonald

    2010-08-01

    Full Text Available Dendritic cells initiate and sustain immune responses by migrating to sites of pathogenic insult, transporting antigens to lymphoid tissues and signaling immune specific activation of T cells through the formation of the immunological synapse. Dendritic cells can also transfer intact, infectious HIV-1 to CD4 T cells through an analogous structure, the infectious synapse. This replication independent mode of HIV-1 transmission, known as trans-infection, greatly increases T cell infection in vitro and is thought to contribute to viral dissemination in vivo. This review outlines the recent data defining the mechanisms of trans-infection and provides a context for the potential contribution of trans-infection in HIV-1 disease.

  5. Networked T cell death following macrophage infection by Mycobacterium tuberculosis.

    Directory of Open Access Journals (Sweden)

    Stephen H-F Macdonald

    Full Text Available BACKGROUND: Depletion of T cells following infection by Mycobacterium tuberculosis (Mtb impairs disease resolution, and interferes with clinical test performance that relies on cell-mediated immunity. A number of mechanisms contribute to this T cell suppression, such as activation-induced death and trafficking of T cells out of the peripheral circulation and into the diseased lungs. The extent to which Mtb infection of human macrophages affects T cell viability however, is not well characterised. METHODOLOGY/PRINCIPAL FINDINGS: We found that lymphopenia (<1.5 × 10(9 cells/l was prevalent among culture-positive tuberculosis patients, and lymphocyte counts significantly improved post-therapy. We previously reported that Mtb-infected human macrophages resulted in death of infected and uninfected bystander macrophages. In the current study, we sought to examine the influence of infected human alveolar macrophages on T cells. We infected primary human alveolar macrophages (the primary host cell for Mtb or PMA-differentiated THP-1 cells with Mtb H37Ra, then prepared cell-free supernatants. The supernatants of Mtb-infected macrophages caused dose-dependent, caspase-dependent, T cell apoptosis. This toxic effect of infected macrophage secreted factors did not require TNF-α or Fas. The supernatant cytotoxic signal(s were heat-labile and greater than 50 kDa in molecular size. Although ESAT-6 was toxic to T cells, other Mtb-secreted factors tested did not influence T cell viability; nor did macrophage-free Mtb bacilli or broth from Mtb cultures. Furthermore, supernatants from Mycobacterium bovis Bacille de Calmette et Guerin (BCG- infected macrophages also elicited T cell death suggesting that ESAT-6 itself, although cytotoxic, was not the principal mediator of T cell death in our system. CONCLUSIONS: Mtb-Infected macrophages secrete heat-labile factors that are toxic to T cells, and may contribute to the immunosuppression seen in tuberculosis as well as

  6. Ureaplasma urealyticum infection and apoptosis of spermatogenic cells

    Institute of Scientific and Technical Information of China (English)

    Xue-JunSHANG; Yu-FengHUANG

    1999-01-01

    Aim: To study the relationship between ureaplasma urealyticum (UU) infection and apoptosis of human spennato-genie cells. Methods: Spermatogenic cells were observed under light microscope with Wright-Giemsa staining andby means of terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate (dUTP)-biotin nick-end labeling(TUNEL) technique. Results: Apoptotic rate of UU-infected males ( 15.5%±6.8% ) was significantly higherthan that of controls (5.2%±2.3 % ). Conclusion: Apoptosis of spermatogenic cells can be caused by UU in-fection, which provides further evidence for UU-induced male infertility.

  7. Impairment of B-cell functions during HIV-1 infection.

    Science.gov (United States)

    Amu, Sylvie; Ruffin, Nicolas; Rethi, Bence; Chiodi, Francesca

    2013-09-24

    A variety of B-cell dysfunctions are manifested during HIV-1 infection, as reported early during the HIV-1 epidemic. It is not unusual that the pathogenic mechanisms presented to elucidate impairment of B-cell responses during HIV-1 infection focus on the impact of reduced T-cell numbers and functions, and lack of germinal center formation in lymphoid tissues. To our understanding, however, perturbation of B-cell phenotype and function during HIV-1 infection may begin at several different B-cell developmental stages. These impairments can be mediated by intrinsic B-cell defects as well as by the lack of proper T-cell help. In this review, we will highlight some of the pathways and molecular interactions leading to B-cell impairment prior to germinal center formation and B-cell activation mediated through the B-cell receptor in response to HIV-1 antigens. Recent studies indicate a regulatory role for B cells on T-cell biology and immune responses. We will discuss some of these novel findings and how these regulatory mechanisms could potentially be affected by the intrinsic defects of B cells taking place during HIV-1 infection.

  8. Germ cell apoptosis induced by Ureaplasma urealyticum infection

    Institute of Scientific and Technical Information of China (English)

    Chen XU; Mei-Ge LU; Jing-Sheng FENG; Qiang-Su Guo; Yi-Fei WANG

    2001-01-01

    Aim: To study the effect of Ureaplasma urealyticum (UU) infection on germ cell apoptosis of male rats. Methods: Male rats were infected artificially with UU serotype 8 (T960) . Morphological changes of germ cells in the seminiferous tubules and the lumen of the epididymides were observed under the light microscope. Fluorescence-conjugated polyclonal antibodies to Fas and Fas ligand (FasL) were used to localize Fas and FasL. TUNEL staining of germ cells and Sertoli cells was performed by the AKPase method. TUNEL-positive rate ( % positive cells) and TUNEL-positive area (area occupied by stained cells) were analysed by KS400 Image Analysis System. The DNA laddering analysis was performed by agarose gels electrophoresis. Results: In those rats infected with UU: (1) Exfoliated germ cells were dramatically increased. Many multinucleated giant cells were found in the seminiferous tubules and the lumen of the epididymides. (2) The number of TUNEL-positive cells and the TUNEL-positive area were significantly increased.(3) The expression of Fas and FasL in germ cells and Sertoli cells was up-regulated. (4) Discrete bands of fragmented DNA were found in the testicular cells. Conclusion: In male rats, germ cell apoptosis was increased in UU infection.

  9. Circulating cytomegalovirus (cmv)-infected endothelial-cells in patients with an active cmv infection

    NARCIS (Netherlands)

    Grefte, A.; van der Giessen, M.; van Son, W.; The, T. Hauw

    1993-01-01

    In 10 of 14 patients with an active cytomegalovirus (CMV) infection, distinctive large cells (35-45 mum in diameter) were present in the peripheral blood. Morphologically these cells closely resembled the classic cytomegalic inclusion cells, generally regarded as a diagnostic hallmark of CMV infecti

  10. In vitro Study on Human Trophoblast Cells Infected with HCMV

    Institute of Scientific and Technical Information of China (English)

    肖娟; 张丹丹; 陈娟娟; 尹宗智; 刘涛; 艾继辉; 陈素华

    2010-01-01

    Human trophoblast cells were isolated and cultured in vitro in order to investigate possible pathogenesis of intrauterine infection caused by HCMV.Trophoblast cells were obtained by compound enzymes digestion and discontinuous percoll gradient.Cells and purity were identified by using immunocytochemistry assay with anti-CK7,Vim and β-hCG antibodies.HCMV AD169 strain replication in isolated trophoblast cells and cell apoptosis were detected at different time points post infection(p.i.).The results showed tha...

  11. [Decontamination of continual cell lines spontaneously infected with mycoplasmas].

    Science.gov (United States)

    Machatková, M; Jurmanová, K; Snejdar, V

    1986-07-01

    The continual cell lines of bovine kidneys MDBK and AUBEK, and porcine kidneys RPD and IBRS, spontaneously infected with Mycoplasma arginini and Acholeplasma laidlawii, were decontaminated by the method of selective elimination. Two elimination procedures were modified to be used for the decontamination: one based on the reduction of infection by the light treatment of the cultures, the other based on the selection of mycoplasma-free cell population through cell clonation. On the basis of a long-continued control of the cell clones a methodical procedure of the preparation of mycoplasma-free cell lines was worked out.

  12. Defective Natural Killer cell antiviral capacity in paediatric HBV infection

    DEFF Research Database (Denmark)

    Heiberg, Ida Louise; Laura J., Pallett; Winther, Thilde Nordmann

    2015-01-01

    cell frequency, phenotype and function in HBV-infected children relative to uninfected children. We observed a selective defect in NK cell IFN-γ production, with conserved cytolytic function, mirroring the functional dichotomy observed in adult infection. Reduced expression of NKp30 on NK cells...... suggests a role of impaired NK-Dendritic Cell (DC) cellular interactions as a potential mechanism leading to reduced IFN-γ production. The finding that NK cells are already defective in paediatric CHB, albeit less extensively than in adult CHB, has potential implications for the timing of antiviral therapy...

  13. Ureaplasma parvum infection alters filamin a dynamics in host cells

    Directory of Open Access Journals (Sweden)

    Brown Mary B

    2011-04-01

    Full Text Available Abstract Background Ureaplasmas are among the most common bacteria isolated from the human urogenital tract. Ureaplasmas can produce asymptomatic infections or disease characterized by an exaggerated inflammatory response. Most investigations have focused on elucidating the pathogenic potential of Ureaplasma species, but little attention has been paid to understanding the mechanisms by which these organisms are capable of establishing asymptomatic infection. Methods We employed differential proteome profiling of bladder tissues from rats experimentally infected with U. parvum in order to identify host cell processes perturbed by colonization with the microbe. Tissues were grouped into four categories: sham inoculated controls, animals that spontaneously cleared infection, asymptomatic urinary tract infection (UTI, and complicated UTI. One protein that was perturbed by infection (filamin A was used to further elucidate the mechanism of U. parvum-induced disruption in human benign prostate cells (BPH-1. BPH-1 cells were evaluated by confocal microscopy, immunoblotting and ELISA. Results Bladder tissue from animals actively colonized with U. parvum displayed significant alterations in actin binding proteins (profilin 1, vinculin, α actinin, and filamin A that regulate both actin polymerization and cell cytoskeletal function pertaining to focal adhesion formation and signal transduction (Fisher's exact test, P U. parvum perturbed the regulation of filamin A. Specifically, infected BPH-1 cells exhibited a significant increase in filamin A phosphorylated at serine2152 (P ≤ 0.01, which correlated with impaired proteolysis of the protein and its normal intracellular distribution. Conclusion Filamin A dynamics were perturbed in both models of infection. Phosphorylation of filamin A occurs in response to various cell signaling cascades that regulate cell motility, differentiation, apoptosis and inflammation. Thus, this phenomenon may be a useful

  14. Dynamics Analysis of an HIV Infection Model including Infected Cells in an Eclipse Stage

    Directory of Open Access Journals (Sweden)

    Shengyu Zhou

    2013-01-01

    Full Text Available In this paper, an HIV infection model including an eclipse stage of infected cells is considered. Some quicker cells in this stage become productively infected cells, a portion of these cells are reverted to the uninfected class, and others will be latent down in the body. We consider CTL-response delay in this model and analyze the effect of time delay on stability of equilibrium. It is shown that the uninfected equilibrium and CTL-absent infection equilibrium are globally asymptotically stable for both ODE and DDE model. And we get the global stability of the CTL-present equilibrium for ODE model. For DDE model, we have proved that the CTL-present equilibrium is locally asymptotically stable in a range of delays and also have studied the existence of Hopf bifurcations at the CTL-present equilibrium. Numerical simulations are carried out to support our main results.

  15. Prion infection of epithelial Rov cells is a polarized event.

    Science.gov (United States)

    Paquet, Sophie; Sabuncu, Elifsu; Delaunay, Jean-Louis; Laude, Hubert; Vilette, Didier

    2004-07-01

    During prion infections, the cellular glycosylphosphatidylinositol-anchored glycoprotein PrP is converted into a conformational isoform. This abnormal conformer is thought to recruit and convert the normal cellular PrP into a likeness of itself and is proposed to be the infectious agent. We investigated the distribution of the PrP protein on the surface of Rov cells, an epithelial cell line highly permissive to prion multiplication, and we found that PrP is primarily expressed on the apical side. We further show that prion transmission to Rov cells is much more efficient if infectivity contacts the apical side, indicating that the apical and basolateral sides of Rov cells are not equally competent for prion infection and adding prions to the list of the conventional infectious agents (viruses and bacteria) that infect epithelial cells in a polarized manner. These data raise the possibility that apically expressed PrP may be involved in this polarized process of infection. This would add further support for a crucial role of PrP at the cell surface in prion infection of target cells.

  16. Peripheral blood cell signatures of Plasmodium falciparum infection during pregnancy

    DEFF Research Database (Denmark)

    Ibitokou, Samad; Oesterholt, Mayke; Brutus, Laurent;

    2012-01-01

    Sequestration of Plasmodium falciparum-infected erythrocytes in placental intervillous spaces causes inflammation and pathology. Knowledge of the profiles of immune cells associated with the physiopathology of pregnancy-associated malaria (PAM) is scarce. We conducted a longitudinal, prospective...

  17. B-cell-independent lymphoid tissue infection by a B-cell-tropic rhadinovirus.

    Science.gov (United States)

    Chao, Brittany; Frederico, Bruno; Stevenson, Philip G

    2015-09-01

    Lymphocytes provide gammaherpesviruses with a self-renewing substrate for persistent infection and with transport to mucosal sites for host exit. Their role in the initial colonization of new hosts is less clear. Murid herpesvirus 4 (MuHV-4), an experimentally accessible, B-cell-tropic rhadinovirus (gamma-2 herpesvirus), persistently infects both immunocompetent and B-cell-deficient mice. A lack of B-cells did not compromise MuHV-4 entry into lymphoid tissue, which involved myeloid cell infection. However, it impaired infection amplification and MuHV-4 exit from lymphoid tissue, which involved myeloid to B-cell transfer.

  18. NK cell subset redistribution during the course of viral infections

    Directory of Open Access Journals (Sweden)

    Enrico eLugli

    2014-08-01

    Full Text Available Natural killer (NK cells are important effectors of innate immunity that play a critical role in the control of human viral infections. Indeed, given their capability to directly recognize virally infected cells without the need of specific antigen presentation, NK cells are on the first line of defense against these invading pathogens. By establishing cellular networks with a variety of cell types such as dendritic cells, NK cells can also amplify anti-viral adaptive immune responses. In turn, viruses evolved and developed several mechanisms to evade NK cell-mediated immune activity. It has been reported that certain viral diseases, including human immunodeficiency virus-1 (HIV-1 as well as cytomegalovirus (CMV infections, are associated with a pathologic redistribution of NK cell subsets in the peripheral blood. In particular, it has been observed the expansion of unconventional CD56neg NK cells, whose effector functions are significantly impaired as compared to that of conventional CD56pos NK cells. In this review, we address the impact of chronic viral infections on the functional and phenotypic perturbations of human NK cell compartment.

  19. CD4+ T cell responses in hepatitis C virus infection

    Institute of Scientific and Technical Information of China (English)

    Nasser Semmo; Paul Klenerman

    2007-01-01

    Hepatitis C virus (HCV) infection is a major cause of liver damage, with virus-induced end-stage disease such as liver cirrhosis and hepatocellular carcinoma resulting in a high rate of morbidity and mortality worldwide. Evidence that CD4+ T cell responses to HCV play an important role in the outcome of acute infection has been shown in several studies. However, the mechanisms behind viral persistence and the failure of CD4+ T cell responses to contain virus are poorly understood. During chronic HCV infection, HCV-specific CD4+ T cell responses are relatively weak or absent whereas in resolved infection these responses are vigorous and multispecific. Persons with a T-helper type Ⅰ profile, which promotes cellular effector mechanisms are thought to be more likely to experience viral clearance, but the overall role of these cells in the immunopathogenesis of chronic liver disease is not known. To define this, much more data is required on the function and specificity of virus-specific CD4+ T cells,especially in the early phases of acute disease and in the liver during chronic infection. The role and possible mechanisms of action of CD4+ T cell responses in determining the outcome of acute and chronic HCV infection will be discussed in this review.

  20. Backward elastic light scattering of malaria infected red blood cells

    Science.gov (United States)

    Lee, Seungjun; Lu, Wei

    2011-08-01

    We investigated the backward light scattering pattern of healthy and malaria (Plasmodium falciparum) parasitized red blood cells. The spectrum could clearly distinguish between predominant ring stage infected blood cells and healthy blood cells. Further, we found that infected samples mixed with different stages of P. falciparum showed different signals, suggesting that even variance in parasite stages could also be detected by the spectrum. These results together with the backward scattering technique suggest the potential of non-invasive diagnosis of malaria through light scattering of blood cells near the surface of human body, such as using eyes or skin surface.

  1. B-Cell Response during Protozoan Parasite Infections

    Directory of Open Access Journals (Sweden)

    María C. Amezcua Vesely

    2012-01-01

    Full Text Available In this review, we discuss how protozoan parasites alter immature and mature B cell compartment. B1 and marginal zone (MZ B cells, considered innate like B cells, are activated during protozoan parasite infections, and they generate short lived plasma cells providing a prompt antibody source. In addition, protozoan infections induce massive B cell response with polyclonal activation that leads to hypergammaglobulnemia with serum antibodies specific for the parasites and self and/or non related antigens. To protect themselves, the parasites have evolved unique ways to evade B cell immune responses inducing apoptosis of MZ and conventional mature B cells. As a consequence of the parasite induced-apoptosis, the early IgM response and an already establish humoral immunity are affected during the protozoan parasite infection. Moreover, some trypanosomatides trigger bone marrow immature B cell apoptosis, influencing the generation of new mature B cells. Simultaneously with their ability to release antibodies, B cells produce cytokines/quemokines that influence the characteristic of cellular immune response and consequently the progression of parasite infections.

  2. In Vitro Brucella suis Infection Prevents the Programmed Cell Death of Human Monocytic Cells

    Science.gov (United States)

    Gross, Antoine; Terraza, Annie; Ouahrani-Bettache, Safia; Liautard, Jean-Pierre; Dornand, Jacques

    2000-01-01

    During the complex interaction between an infectious agent and a host organism, the pathogen can interfere with the host cell's programmed death to its own benefit. Induction or prevention of host cell apoptosis appears to be a critical step for determining the infection outcome. Members of the gram-negative bacterial genus Brucella are intracellular pathogens which preferentially invade monocytic cells and develop within these cells. We investigated the effect of Brucella suis infection on apoptosis of human monocytic phagocytes. The present study provides evidence that Brucella infection inhibited spontaneously occurring apoptosis in human monocytes. Prevention of monocyte apoptosis was not mediated by Brucella lipopolysaccharide and required bacterial survival within infected cells. Both invaded and noninvaded cells were protected, indicating that soluble mediators released during infection were involved in the phenomenon. Analysis of Brucella-infected monocytes revealed specific overexpression of the A1 gene, a member of the bcl-2 family implicated in the survival of hematopoietic cells. Brucella infection also rendered macrophage-like cells resistant to Fas ligand- or gamma interferon-induced apoptosis, suggesting that Brucella infection protected host cells from several cytotoxic processes occurring at different steps of the immune response. The present data clearly show that Brucella suis modulated the monocyte/macrophage's apoptotic response to the advantage of the pathogen, thus preventing host cell elimination. This might represent a strategy for Brucella development in infected hosts. PMID:10603407

  3. Invariant NKT cells: regulation and function during viral infection.

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    Jennifer A Juno

    Full Text Available Natural killer T cells (NKT cells represent a subset of T lymphocytes that express natural killer (NK cell surface markers. A subset of NKT cells, termed invariant NKT cells (iNKT, express a highly restricted T cell receptor (TCR and respond to CD1d-restricted lipid ligands. iNKT cells are now appreciated to play an important role in linking innate and adaptive immune responses and have been implicated in infectious disease, allergy, asthma, autoimmunity, and tumor surveillance. Advances in iNKT identification and purification have allowed for the detailed study of iNKT activity in both humans and mice during a variety of chronic and acute infections. Comparison of iNKT function between non-pathogenic simian immunodeficiency virus (SIV infection models and chronic HIV-infected patients implies a role for iNKT activity in controlling immune activation. In vitro studies of influenza infection have revealed novel effector functions of iNKT cells including IL-22 production and modulation of myeloid-derived suppressor cells, but ex vivo characterization of human iNKT cells during influenza infection are lacking. Similarly, as recent evidence suggests iNKT involvement in dengue virus pathogenesis, iNKT cells may modulate responses to a number of emerging pathogens. This Review will summarize current knowledge of iNKT involvement in responses to viral infections in both human and mouse models and will identify critical gaps in knowledge and opportunities for future study. We will also highlight recent efforts to harness iNKT ligands as vaccine adjuvants capable of improving vaccination-induced cellular immune responses.

  4. Mycobacterium tuberculosis infection induces non-apoptotic cell death of human dendritic cells

    LENUS (Irish Health Repository)

    Ryan, Ruth CM

    2011-10-24

    Abstract Background Dendritic cells (DCs) connect innate and adaptive immunity, and are necessary for an efficient CD4+ and CD8+ T cell response after infection with Mycobacterium tuberculosis (Mtb). We previously described the macrophage cell death response to Mtb infection. To investigate the effect of Mtb infection on human DC viability, we infected these phagocytes with different strains of Mtb and assessed viability, as well as DNA fragmentation and caspase activity. In parallel studies, we assessed the impact of infection on DC maturation, cytokine production and bacillary survival. Results Infection of DCs with live Mtb (H37Ra or H37Rv) led to cell death. This cell death proceeded in a caspase-independent manner, and without nuclear fragmentation. In fact, substrate assays demonstrated that Mtb H37Ra-induced cell death progressed without the activation of the executioner caspases, 3\\/7. Although the death pathway was triggered after infection, the DCs successfully underwent maturation and produced a host-protective cytokine profile. Finally, dying infected DCs were permissive for Mtb H37Ra growth. Conclusions Human DCs undergo cell death after infection with live Mtb, in a manner that does not involve executioner caspases, and results in no mycobactericidal effect. Nonetheless, the DC maturation and cytokine profile observed suggests that the infected cells can still contribute to TB immunity.

  5. Effect of herpesvirus infection on pancreatic duct cell secretion

    Institute of Scientific and Technical Information of China (English)

    Péter Hegyi; András Varró; Mária K Kovács; Mike A Gray; Barry E Argent; Zsolt Boldogk(o)i; Balázs (O)rd(o)g; Zoltán Rakonczai Jr; Tamás Takács; János Lonovics; Annamária Szabolcs; Réka Sári; András Tóth; Julius G Papp

    2005-01-01

    AIM: To examine the effect of acute infection caused by herpesvirus (pseudorabies virus, PRV) on pancreatic ductal secretion.METHODS: The virulent Ba-DupGreen (BDG) and nonvirulent Ka-RREpOlacgfp (KEG) genetically modified strains of PRV were used in this study and both of them contain the gene for green fluorescent protein (GFP). Small intra/interlobular ducts were infected with BDG virus (107 PFU/mL for 6 h) or with KEG virus (1010 PFU/mL for 6 h), while non-infected ducts were incubated only with the culture media. The ducts were then cultured for a further 18 h.The rate of HCO3- secretion [base efflux -J(B-)] was determined from the buffering capacity of the cells and the initial rate of intracellular acidification (1) after sudden blockage of basolateral base loaders with dihydro-4,4,-diisothiocyanatostilbene-2,2,-disulfonic acid (500 μmol/L)and amiloride (200 μmol/L), and (2) after alkali loading the ducts by exposure to NH4Cl. All the experiments were performed in HCO3--buffered Ringer solution at 37 ℃ (n = 5ducts for each experimental condition). Viral structural proteins were visualized by immunohistochemistry. Virallyencoded GFP and immunofluorescence signals were recorded by a confocal laser scanning microscope.RESULTS: The BDG virus infected the majority of accessible cells of the duct as judged by the appearance of GFP and viral antigens in the ductal cells. KEG virus caused a similarly high efficiency of infection. After blockage of basolateral base loaders, BDG infection significantly elevated -J(B-) 24 h after the infection, compared to the non-infected group. However, KEG infection did not modify -J(B-). After alkali loading the ducts, -J(B-) was significantly elevated in the BDG group compared to the control group 24 h after the infection. As we found with the inhibitor stop method, no change was observed in the group KEG compared to the non-infected group.CONCLUSION: Incubation with the BDG or KEG strains of PRV results in an effective

  6. Modulation of host-cell MAPkinase signaling during fungal infection

    Directory of Open Access Journals (Sweden)

    Nir Osherov

    2015-10-01

    Full Text Available Fungal infections contribute substantially to human suffering and mortality. The interaction between fungal pathogens and their host involves the invasion and penetration of the surface epithelium, activation of cells of the innate immune system and the generation of an effective response to block infection. Numerous host-cell signaling pathways are activated during fungal infection. This review will focus on the main fungal pathogens Aspergillus fumigatus, Candida albicans and Cryptococcus neoformans and their ability to activate the host MAP-kinase signaling pathways leading to cytokine secretion, increased cell motility and killing of the pathogen. Both epithelial and innate immune cells specifically recognize fungal antigens and in particular cell surface polysaccharides such as β-glucans and react to them by activating multiple signaling pathways, including those containing MAP-kinase modules. Recent findings suggest that the host response to fungal infection utilizes the MAP-kinase pathway to differentiate between commensal and pathogenic fungi to selectively react only to the pathogenic forms. However, the paucity of relevant publications strongly emphasize that our understanding of host MAP-kinase signaling in response to fungal infection is still at a very early stage. It is clear, based on studies of host MAP-kinase signaling during viral and bacterial infections, that in fungi as well, a wealth of exciting findings await us.

  7. Isolation of single Chlamydia-infected cells using laser microdissection.

    Science.gov (United States)

    Podgorny, Oleg V; Polina, Nadezhda F; Babenko, Vladislav V; Karpova, Irina Y; Kostryukova, Elena S; Govorun, Vadim M; Lazarev, Vassili N

    2015-02-01

    Chlamydia are obligate intracellular parasites of humans and animals that cause a wide range of acute and chronic infections. To elucidate the genetic basis of chlamydial parasitism, several approaches for making genetic modifications to Chlamydia have recently been reported. However, the lack of the available methods for the fast and effective selection of genetically modified bacteria restricts the application of genetic tools. We suggest the use of laser microdissection to isolate of single live Chlamydia-infected cells for the re-cultivation and whole-genome sequencing of single inclusion-derived Chlamydia. To visualise individual infected cells, we made use of the vital labelling of inclusions with the fluorescent Golgi-specific dye BODIPY® FL C5-ceramide. We demonstrated that single Chlamydia-infected cells isolated by laser microdissection and placed onto a host cell monolayer resulted in new cycles of infection. We also demonstrated the successful use of whole-genome sequencing to study the genomic variability of Chlamydia derived from a single inclusion. Our work provides the first evidence of the successful use of laser microdissection for the isolation of single live Chlamydia-infected cells, thus demonstrating that this method can help overcome the barriers to the fast and effective selection of Chlamydia.

  8. Peripheral blood cell signatures of Plasmodium falciparum infection during pregnancy.

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    Samad Ibitokou

    Full Text Available Sequestration of Plasmodium falciparum-infected erythrocytes in placental intervillous spaces causes inflammation and pathology. Knowledge of the profiles of immune cells associated with the physiopathology of pregnancy-associated malaria (PAM is scarce. We conducted a longitudinal, prospective study, both in Benin and Tanzania, including ∼1000 pregnant women in each site with systematic follow-up at scheduled antenatal visits until delivery. We used ex vivo flow cytometry to identify peripheral blood mononuclear cell (PBMC profiles that are associated with PAM and anaemia, determining the phenotypic composition and activation status of PBMC in selected sub-groups with and without PAM both at inclusion and at delivery in a total of 302 women. Both at inclusion and at delivery PAM was associated with significantly increased frequencies both of B cells overall and of activated B cells. Infection-related profiles were otherwise quite distinct at the two different time-points. At inclusion, PAM was associated with anaemia, with an increased frequency of immature monocytes and with a decreased frequency of regulatory T cells (Treg. At delivery, infected women presented with significantly fewer plasmacytoid dendritic cells (DC, more myeloid DC expressing low levels of HLA-DR, and more effector T cells (Teff compared to uninfected women. Independent associations with an increased risk of anaemia were found for altered antigen-presenting cell frequencies at inclusion, but for an increased frequency of Teff at delivery. Our findings emphasize the prominent role played by B cells during PAM whenever it arises during pregnancy, whilst also revealing signature changes in other circulating cell types that, we conclude, primarily reflect the relative duration of the infections. Thus, the acute, recently-acquired infections present at delivery were marked by changes in DC and Teff frequencies, contrasting with infections at inclusion, considered chronic in

  9. NK cells during dengue disease and their recognition of dengue virus-infected cells

    Directory of Open Access Journals (Sweden)

    Davis Alexander Beltrán

    2014-05-01

    Full Text Available The innate immune response, in addition to the B and T cell response, plays a role in protection against dengue virus (DENV infection and the degree of disease severity. Early activation of NK cells and type-I interferon-dependent immunity may be important in limiting viral replication during the early stages of DENV infection and thus reducing subsequent pathogenesis. NK cells may also produce cytokines that reduce inflammation and tissue injury. On the other hand, NK cells are also capable of inducing liver injury at early-time points of DENV infection. In vitro, NK cells can kill antibody-coated DENV-infected cells through antibody-dependent cell-mediated cytotoxicity (ADCC. In additional, NK cells may directly recognize DENV-infected cells through their activating receptors, although the increase in HLA class I expression may allow infected cells to escape the NK response. Recently, genome-wide association studies (GWAS have shown an association between MICB and MICA, which encode ligands of the activating NK receptor NKG2D, and dengue disease outcome. This review focuses on recognition of DENV-infected cells by NK cells and on the regulation of expression of NK cell ligands by DENV.

  10. Dendritic Cells Enhance HIV Infection of Memory CD4(+) T Cells in Human Lymphoid Tissues.

    Science.gov (United States)

    Reyes-Rodriguez, Angel L; Reuter, Morgan A; McDonald, David

    2016-02-01

    Dendritic cells (DCs) play a key role in controlling infections by coordinating innate and adaptive immune responses to invading pathogens. Paradoxically, DCs can increase HIV-1 dissemination in vitro by binding and transferring infectious virions to CD4(+) T cells, a process called transinfection. Transinfection has been well characterized in cultured cell lines and circulating primary T cells, but it is unknown whether DCs enhance infection of CD4(+) T cells in vivo. In untreated HIV infection, massive CD4(+) T-cell infection and depletion occur in secondary lymphoid tissues long before decline is evident in the peripheral circulation. To study the role of DCs in HIV infection of lymphoid tissues, we utilized human tonsil tissues, cultured either as tissue blocks or as aggregate suspension cultures, in single-round infection experiments. In these experiments, addition of monocyte-derived DCs (MDDCs) to the cultures increased T-cell infection, particularly in CD4(+) T cells expressing lower levels of HLA-DR. Subset analysis demonstrated that MDDCs increased HIV-1 infection of central and effector memory T-cell populations. Depletion of endogenous myeloid DCs (myDCs) from the cultures decreased memory T-cell infection, and readdition of MDDCs restored infection to predepletion levels. Using an HIV-1 fusion assay, we found that MDDCs equally increased HIV delivery into naïve, central, and effector memory T cells in the cultures, whereas predepletion of myDCs reduced fusion into memory T cells. Together, these data suggest that resident myDCs facilitate memory T-cell infection in lymphoid tissues, implicating DC-mediated transinfection in driving HIV dissemination within these tissues in untreated HIV/AIDS.

  11. Human neuronal cell protein responses to Nipah virus infection

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    Hassan Sharifah

    2007-06-01

    Full Text Available Abstract Background Nipah virus (NiV, a recently discovered zoonotic virus infects and replicates in several human cell types. Its replication in human neuronal cells, however, is less efficient in comparison to other fully susceptible cells. In the present study, the SK-N-MC human neuronal cell protein response to NiV infection is examined using proteomic approaches. Results Method for separation of the NiV-infected human neuronal cell proteins using two-dimensional polyacrylamide gel electrophoresis (2D-PAGE was established. At least 800 protein spots were resolved of which seven were unique, six were significantly up-regulated and eight were significantly down-regulated. Six of these altered proteins were identified using mass spectrometry (MS and confirmed using MS/MS. The heterogenous nuclear ribonucleoprotein (hnRNP F, guanine nucleotide binding protein (G protein, voltage-dependent anion channel 2 (VDAC2 and cytochrome bc1 were present in abundance in the NiV-infected SK-N-MC cells in contrast to hnRNPs H and H2 that were significantly down-regulated. Conclusion Several human neuronal cell proteins that are differentially expressed following NiV infection are identified. The proteins are associated with various cellular functions and their abundance reflects their significance in the cytopathologic responses to the infection and the regulation of NiV replication. The potential importance of the ratio of hnRNP F, and hnRNPs H and H2 in regulation of NiV replication, the association of the mitochondrial protein with the cytopathologic responses to the infection and induction of apoptosis are highlighted.

  12. Early events associated with infection of Epstein-Barr virus infection of primary B-cells.

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    Sabyasachi Halder

    Full Text Available Epstein Barr virus (EBV is closely associated with the development of a vast number of human cancers. To develop a system for monitoring early cellular and viral events associated with EBV infection a self-recombining BAC containing 172-kb of the Epstein Barr virus genome BAC-EBV designated as MD1 BAC (Chen et al., 2005, J.Virology was used to introduce an expression cassette of green fluorescent protein (GFP by homologous recombination, and the resultant BAC clone, BAC-GFP-EBV was transfected into the HEK 293T epithelial cell line. The resulting recombinant GFP EBV was induced to produce progeny virus by chemical inducer from the stable HEK 293T BAC GFP EBV cell line and the virus was used to immortalize human primary B-cell as monitored by green fluorescence and outgrowth of the primary B cells. The infection, B-cell activation and cell proliferation due to GFP EBV was monitored by the expression of the B-cell surface antigens CD5, CD10, CD19, CD23, CD39, CD40 , CD44 and the intercellular proliferation marker Ki-67 using Flow cytometry. The results show a dramatic increase in Ki-67 which continues to increase by 6-7 days post-infection. Likewise, CD40 signals showed a gradual increase, whereas CD23 signals were increased by 6-12 hours, maximally by 3 days and then decreased. Monitoring the viral gene expression pattern showed an early burst of lytic gene expression. This up-regulation of lytic gene expression prior to latent genes during early infection strongly suggests that EBV infects primary B-cell with an initial burst of lytic gene expression and the resulting progeny virus is competent for infecting new primary B-cells. This process may be critical for establishment of latency prior to cellular transformation. The newly infected primary B-cells can be further analyzed for investigating B cell activation due to EBV infection.

  13. Vaccination against feline immunodeficiency virus using fixed infected cells

    NARCIS (Netherlands)

    Horzinek, M.C.; Verschoor, E.J.; Vliet, A.L.W. van; Egberink, H.F.; Hesselink, W.; Alphen, W.E. van; Joosten, I.; Boog, C.J.P.; Ronde, A. de

    1995-01-01

    Crandell feline kidney cells and feline thymocytes, either feline immunodeficiency virus (FIV) infected or uninfected, were fixed with paraformaldehyde and used to vaccinate cats. The cells were mixed with a 30:70 water/mineral oil emulsion containing 250 mu g ml−1 N-acetyl-d-glucosaminyl-beta-(1 4)

  14. Hepatitis C virus infection of cholangiocarcinoma cell lines

    NARCIS (Netherlands)

    Fletcher, Nicola F.; Humphreys, Elizabeth; Jennings, Elliott; Osburn, William; Lissauer, Samantha; Wilson, Garrick K.; van Ijzendoorn, Sven C. D.; Baumert, Thomas F.; Balfe, Peter; Afford, Simon; McKeating, Jane A.

    2015-01-01

    Hepatitis C virus (HCV) infects the liver and hepatocytes are the major cell type supporting viral replication. Hepatocytes and cholangiocytes derive from a common hepatic progenitor cell that proliferates during inflammatory conditions, raising the possibility that cholangiocytes may support HCV re

  15. Apoptosis in HEp-2 cells infected with Ureaplasma diversum.

    Science.gov (United States)

    Amorim, Aline Teixeira; Marques, Lucas Miranda; Santos, Angelita Maria Oliveira Gusmão; Martins, Hellen Braga; Barbosa, Maysa Santos; Rezende, Izadora Souza; Andrade, Ewerton Ferraz; Campos, Guilherme Barreto; Lobão, Tássia Neves; Cortez, Beatriz Araujo; Monezi, Telma Alvez; Machado-Santelli, Glaucia Maria; Timenetsky, Jorge

    2014-09-04

    Bacterial pathogens have many strategies for infecting and persisting in host cells. Adhesion, invasion and intracellular life are important features in the biology of mollicutes. The intracellular location of Ureaplasma diversum may trigger disturbances in the host cell. This includes activation or inhibition of pro and anti-apoptotic factors, which facilitate the development of host damage. The aim of the present study was to associate U. diversum infection in HEp-2 cells and apoptosis induction. Cells were infected for 72hs with four U. diversum clinical isolates and an ATCC strain. The U. diversum invasion was analyzed by Confocal Laser Scanning Microscopy and gentamicin invasion assay. The apoptosis was evaluated using pro-apoptotic and anti-apoptotic gene expression, and FITC Annexin V/Dead Cell Apoptosis Kit. The number of internalized ureaplasma in HEp-2 cells increased significantly throughout the infection. The flow cytometry analysis with fluorochromes to detect membrane depolarization and gene expression for caspase 2, 3 and 9 increased in infected cells after 24 hours. However, after 72 hours a considerable decrease of apoptotic cells was observed. The data suggests that apoptosis may be initially induced by some isolates in association with HEp-2 cells, but over time, there was no evidence of apoptosis in the presence of ureaplasma and HEp-2 cells. The initial increase and then decrease in apoptosis could be related to bacterial pathogen-associated molecular pattern (PAMPS). Moreover, the isolates of U. diversum presented differences in the studied parameters for apoptosis. It was also observed that the amount of microorganisms was not proportional to the induction of apoptosis in HEp-2 cells.

  16. Multiploid CD61+ cells are the pre-dominant cell lineage infected during acute dengue virus infection in bone marrow.

    Directory of Open Access Journals (Sweden)

    Kristina B Clark

    Full Text Available Depression of the peripheral blood platelet count during acute infection is a hallmark of dengue. This thrombocytopenia has been attributed, in part, to an insufficient level of platelet production by megakaryocytes that reside in the bone marrow (BM. Interestingly, it was observed that dengue patients experience BM suppression at the onset of fever. However, few studies focus on the interaction between dengue virus (DENV and megakaryocytes and how this interaction can lead to a reduction in platelets. In the studies reported herein, BM cells from normal healthy rhesus monkeys (RM and humans were utilized to identify the cell lineage(s that were capable of supporting virus infection and replication. A number of techniques were employed in efforts to address this issue. These included the use of viral RNA quantification, nonstructural protein and infectivity assays, phenotypic studies utilizing immunohistochemical staining, anti-differentiation DEAB treatment, and electron microscopy. Cumulative results from these studies revealed that cells in the BM were indeed highly permissive for DENV infection, with human BM having higher levels of viral production compared to RM. DENV-like particles were predominantly observed in multi-nucleated cells that expressed CD61+. These data suggest that megakaryocytes are likely the predominant cell type infected by DENV in BM, which provides one explanation for the thrombocytopenia and the dysfunctional platelets characteristic of dengue virus infection.

  17. Proinflammatory Response of Human Trophoblastic Cells to Brucella abortus Infection and upon Interactions with Infected Phagocytes.

    Science.gov (United States)

    Fernández, Andrea G; Ferrero, Mariana C; Hielpos, M Soledad; Fossati, Carlos A; Baldi, Pablo C

    2016-02-01

    Trophoblasts are targets of infection by Brucella spp. but their role in the pathophysiology of pregnancy complications of brucellosis is unknown. Here we show that Brucella abortus invades and replicates in the human trophoblastic cell line Swan-71 and that the intracellular survival of the bacterium depends on a functional virB operon. The infection elicited significant increments of interleukin 8 (IL8), monocyte chemotactic protein 1 (MCP-1), and IL6 secretion, but levels of IL1beta and tumor necrosis factor-alpha (TNF-alpha) did not vary significantly. Such proinflammatory response was not modified by the absence of the Brucella TIR domain-containing proteins BtpA and BtpB. The stimulation of Swan-71 cells with conditioned medium (CM) from B. abortus-infected human monocytes (THP-1 cells) or macrophages induced a significant increase of IL8, MCP-1 and IL6 as compared to stimulation with CM from non-infected cells. Similar results were obtained when stimulation was performed with CM from infected neutrophils. Neutralization studies showed that IL1beta and/or TNF-alpha mediated the stimulating effects of CM from infected phagocytes. Reciprocally, stimulation of monocytes and neutrophils with CM from Brucella-infected trophoblasts increased IL8 and/or IL6 secretion. These results suggest that human trophoblasts may provide a local inflammatory environment during B. abortus infections either through a direct response to the pathogen or through interactions with monocytes/macrophages or neutrophils, potentially contributing to the pregnancy complications of brucellosis.

  18. Activation of Natural Killer cells during microbial infections

    Directory of Open Access Journals (Sweden)

    Amir eHorowitz

    2012-01-01

    Full Text Available Natural killer (NK cells are large granular lymphocytes that express a diverse array of germline encoded inhibitory and activating receptors for MHC Class I and Class I-like molecules, classical co-stimulatory ligands and cytokines. The ability of NK cells to be very rapidly activated by inflammatory cytokines, to secrete effector cytokines and to kill infected or stressed host cells, suggests that they may be among the very early responders during infection. Recent studies have also identified a small number of pathogen-derived ligands that can bind to NK cell surface receptors and directly induce their activation. Here we review recent studies that have begun to elucidate the various pathways by which viral, bacterial and parasite pathogens activate NK cells. We also consider two emerging themes of NK cell-pathogen interactions, namely their contribution to adaptive immune responses and their potential to take on regulatory and immunomodulatory functions.

  19. Mechanisms Underlying T Cell Immunosenescence: Aging and Cytomegalovirus Infection

    Science.gov (United States)

    Tu, Wenjuan; Rao, Sudha

    2016-01-01

    The ability of the human immune system to protect against infectious disease declines with age and efficacy of vaccination reduces significantly in the elderly. Aging of the immune system, also termed as immunosenescence, involves many changes in human T cell immunity that is characterized by a loss in naïve T cell population and an increase in highly differentiated CD28- memory T cell subset. There is extensive data showing that latent persistent human cytomegalovirus (HCMV) infection is also associated with age-related immune dysfunction in the T cells, which might enhance immunosenescence. Understanding the molecular mechanisms underlying age-related and HCMV-related immunosenescence is critical for the development of effective age-targeted vaccines and immunotherapies. In this review, we will address the role of both aging and HCMV infection that contribute to the T cell senescence and discuss the potential molecular mechanisms in aged T cells. PMID:28082969

  20. Modeling dynamics of HIV infected cells using stochastic cellular automaton

    Science.gov (United States)

    Precharattana, Monamorn; Triampo, Wannapong

    2014-08-01

    Ever since HIV was first diagnosed in human, a great number of scientific works have been undertaken to explore the biological mechanisms involved in the infection and progression of the disease. Several cellular automata (CA) models have been introduced to gain insights into the dynamics of the disease progression but none of them has taken into account effects of certain immune cells such as the dendritic cells (DCs) and the CD8+ T lymphocytes (CD8+ T cells). In this work, we present a CA model, which incorporates effects of the HIV specific immune response focusing on the cell-mediated immunities, and investigate the interaction between the host immune response and the HIV infected cells in the lymph nodes. The aim of our work is to propose a model more realistic than the one in Precharattana et al. (2010) [10], by incorporating roles of the DCs, the CD4+ T cells, and the CD8+ T cells into the model so that it would reproduce the HIV infection dynamics during the primary phase of HIV infection.

  1. Chlamydia pneumoniae respiratory infection after allogeneic stem cell transplantation.

    Science.gov (United States)

    Geisler, William M; Corey, Lawrence

    2002-03-27

    Chlamydia pneumoniae is a common cause of upper and lower respiratory tract infections in immunocompetent patients; however, its role as a respiratory pathogen in immunocompromised hosts has been infrequently recognized. We describe C. pneumoniae lower respiratory tract infection in a 19-year-old male after allogeneic stem cell transplantation. The patient developed fever on day +14, and a subsequent computed tomography scan of the chest revealed a right lateral pleural-based opacity, which was then resected during thoracoscopy. Diagnosis was made by culture and staining of the resected tissue with C. pneumoniae-specific monoclonal antibodies, and azithromycin was administered. To the best of our knowledge, this is the first report of C. pneumoniae respiratory infection after stem cell or marrow transplantation. C. pneumoniae often coexists with other etiologic agents of pneumonia in immunocompromised patients. Considering the infrequency of infections from this organism in this clinical setting, one must still rule out other more likely respiratory pathogens.

  2. Helicobacter pylori infection generates genetic instability in gastric cells

    DEFF Research Database (Denmark)

    Machado, Ana Manuel; Figueiredo, C.; Seruca, R.

    2010-01-01

    The discovery that Helicobacter pylori is associated with gastric cancer has led to numerous studies that investigate the mechanisms by which H. pylori induces carcinogenesis. Gastric cancer shows genetic instability both in nuclear and mitochondrial DNA, besides impairment of important DNA repair...... pathways. As such, this review highlights the consequences of H. pylori infection on the integrity of DNA in the host cells. By down-regulating major DNA repair pathways, H. pylori infection has the potential to generate mutations. In addition, H. pylori infection can induce direct changes on the DNA...... of the host, such as oxidative damage, methylation, chromosomal instability, microsatellite instability, and mutations. Interestingly, H. pylori infection generates genetic instability in nuclear and mitochondrial DNA. Based on the reviewed literature we conclude that H. pylori infection promotes gastric...

  3. Morphology and infectivity of virus that persistently caused infection in an AGS cell line.

    Science.gov (United States)

    Ooi, Yukimasa; Daikoku, Eriko; Wu, Hong; Aoki, Hiroaki; Morita, Chizuko; Nakano, Takashi; Kohno, Takehiro; Takasaki, Tomohiko; Sano, Kouichi

    2011-12-01

    A recent report has indicated that proteins and genes of simian virus 5 (SV5) are detected in a human gastric adenocarcinoma (AGS) cell line, which is widely provided for oncology, immunology, and microbiology research. However, the production of infective virions has not been determined in this cell line. In this study, the morphology and infectivity of the virus particles of the AGS cell line were studied by light and electron microscopy and virus transmission assay. The virus particles were approximately 176.0 ± 41.1 nm in diameter. The particles possessed projections 8-12 nm long on the surface and contained a nucleocapsid determined to be 13-18 nm in width and less than 1,000 nm in length. The virus was transmissible to the Vero cell line, induced multinuclear giant cell formation, and reproduced the same shape of antigenic virions. In this study, the persistently infected virus in the AGS cell line was determined to be infective and form reproducible virions, and a new morphological feature of SV5 was determined.

  4. Receptor-Dependent Coronavirus Infection of Dendritic Cells

    Science.gov (United States)

    Turner, Brian C.; Hemmila, Erin M.; Beauchemin, Nicole; Holmes, Kathryn V.

    2004-01-01

    In several mammalian species, including humans, coronavirus infection can modulate the host immune response. We show a potential role of dendritic cells (DC) in murine coronavirus-induced immune modulation and pathogenesis by demonstrating that the JAW SII DC line and primary DC from BALB/c mice and p/p mice with reduced expression of the murine coronavirus receptor, murine CEACAM1a, are susceptible to murine coronavirus infection by a receptor-dependent pathway. PMID:15113927

  5. Dendritic Cell-Based Vaccine Against Fungal Infection.

    Science.gov (United States)

    Ueno, Keigo; Urai, Makoto; Ohkouchi, Kayo; Miyazaki, Yoshitsugu; Kinjo, Yuki

    2016-01-01

    Several pathogenic fungi, including Cryptococcus gattii, Histoplasma capsulatum, Coccidioides immitis, and Penicillium marneffei, cause serious infectious diseases in immunocompetent humans. However, currently, prophylactic and therapeutic vaccines are not clinically used. In particular, C. gattii is an emerging pathogen and thus far protective immunity against this pathogen has not been well characterized. Experimental vaccines such as component and attenuated live vaccines have been used as tools to study protective immunity against fungal infection. Recently, we developed a dendritic cell (DC)-based vaccine to study protective immunity against pulmonary infection by highly virulent C. gattii strain R265 that was clinically isolated from bronchial washings of infected patients during the Vancouver Island outbreak. In this approach, bone marrow-derived DCs (BMDCs) are pulsed with heat-killed C. gattii and then transferred into mice prior to intratracheal infection. This DC vaccine significantly increases interleukin 17A (IL-17A)-, interferon gamma (IFN-γ)-, and tumor necrosis factor alpha (TNF-α)-producing T cells in the lungs and spleen and ameliorates the pathology, fungal burden, and mortality following C. gattii infection. This approach may result in the development of a new means of controlling lethal fungal infections. In this chapter, we describe the procedures of DC vaccine preparation and murine pulmonary infection model for analysis of immune response against C. gattii.

  6. Ebola virus infection induces irregular dendritic cell gene expression.

    Science.gov (United States)

    Melanson, Vanessa R; Kalina, Warren V; Williams, Priscilla

    2015-02-01

    Filoviruses subvert the human immune system in part by infecting and replicating in dendritic cells (DCs). Using gene arrays, a phenotypic profile of filovirus infection in human monocyte-derived DCs was assessed. Monocytes from human donors were cultured in GM-CSF and IL-4 and were infected with Ebola virus Kikwit variant for up to 48 h. Extracted DC RNA was analyzed on SuperArray's Dendritic and Antigen Presenting Cell Oligo GEArray and compared to uninfected controls. Infected DCs exhibited increased expression of cytokine, chemokine, antiviral, and anti-apoptotic genes not seen in uninfected controls. Significant increases of intracellular antiviral and MHC I and II genes were also noted in EBOV-infected DCs. However, infected DCs failed to show any significant difference in co-stimulatory T-cell gene expression from uninfected DCs. Moreover, several chemokine genes were activated, but there was sparse expression of chemokine receptors that enabled activated DCs to home to lymph nodes. Overall, statistically significant expression of several intracellular antiviral genes was noted, which may limit viral load but fails to stop replication. EBOV gene expression profiling is of vital importance in understanding pathogenesis and devising novel therapeutic treatments such as small-molecule inhibitors.

  7. Vertebrate Cell Cycle Modulates Infection by Protozoan Parasites

    Science.gov (United States)

    Dvorak, James A.; Crane, Mark St. J.

    1981-11-01

    Synchronized HeLa cell populations were exposed to Trypanosoma cruzi or Toxoplasma gondii, obligate intracellular protozoan parasites that cause Chagas' disease and toxoplasmosis, respectively, in humans. The ability of the two parasites to infect HeLa cells increased as the HeLa cells proceeded from the G1 phase to the S phase of their growth cycle and decreased as the cells entered G2-M. Characterization of the S-phase cell surface components responsible for this phenomenon could be beneficial in the development of vaccines against these parasitic diseases.

  8. Role And Relevance Of Mast Cells In Fungal Infections

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    Rohit eSaluja

    2012-06-01

    Full Text Available In addition to their detrimental role in allergic diseases, mast cells (MCs are well known to be important cells of the innate immune system. In the last decade, they have been shown to contribute significantly to optimal host defense against numerous pathogens including parasites, bacteria, and viruses. The contribution of MCs to the immune responses in fungal infections, however, is largely unknown. In this review, we first discuss key features of mast cell responses to pathogens in general and then summarize the current knowledge on the function of MCs in the defense against fungal pathogens. We especially focus on the potential and proven mechanisms by which MC can detect fungal infections and on possible MC effector mechanisms in protecting from fungal infections.

  9. Regulation of cell survival and death during Flavivirus infections

    Institute of Scientific and Technical Information of China (English)

    Sounak; Ghosh; Roy; Beata; Sadigh; Emmanuel; Datan; Richard; A; Lockshin; Zahra; Zakeri

    2014-01-01

    Flaviviruses, ss(+) RNA viruses, include many of mankind’s most important pathogens. Their pathogenicity derives from their ability to infect many types of cells including neurons, to replicate, and eventually to kill the cells. Flaviviruses can activate tumor necrosis factor α and both intrinsic(Bax-mediated) and extrinsic pathways to apoptosis. Thus they can use many approaches for activating these pathways. Infection can lead to necrosis if viral load is extremely high or to other types of cell death if routes to apoptosis are blocked. Dengue and Japanese Encephalitis Virus can also activate autophagy. In this case the autophagy temporarily spares the infected cell, allowing a longer period of reproduction for the virus, and the autophagy further protects the cell against other stresses such as those caused by reactive oxygen species. Several of the viral proteins have been shown to induce apoptosis or autophagy on their own, independent of the presence of other viral proteins. Given the versatility of these viruses to adapt to and manipulate the metabolism, and thus to control the survival of, the infected cells, we need to understand much better how the specific viral proteins affect the pathways to apoptosis and autophagy. Only in this manner will we be able to minimize the pathology that they cause.

  10. The split personality of regulatory T cells in HIV infection.

    Science.gov (United States)

    Chevalier, Mathieu F; Weiss, Laurence

    2013-01-03

    Natural regulatory T cells (Tregs) participate in responses to various chronic infections including HIV. HIV infection is associated with a progressive CD4 lymphopenia and defective HIV-specific CD8 responses known to play a key role in the control of viral replication. Persistent immune activation is a hallmark of HIV infection and is involved in disease progression independent of viral load. The consequences of Treg expansion, observed in HIV infection, could be either beneficial, by suppressing generalized T-cell activation, or detrimental, by weakening HIV-specific responses and thus contributing to viral persistence. The resulting balance between Tregs contrasting outcomes might have critical implications in pathogenesis. Topics covered in this review include HIV-induced alterations of Tregs, Treg cell dynamics in blood and tissues, Treg-suppressive function, and the relationship between Tregs and immune activation. This review also provides a focus on the role of CD39(+) Tregs and other regulatory cell subsets. All these issues will be explored in different situations including acute and chronic infection, antiretroviral treatment-mediated viral control, and spontaneous viral control. Results must be interpreted with regard to both the Treg definition used in context and to the setting of the disease in an attempt to draw clearer conclusions from the apparently conflicting results.

  11. Apoptosis transcriptional mechanism of feline infectious peritonitis virus infected cells.

    Science.gov (United States)

    Shuid, Ahmad Naqib; Safi, Nikoo; Haghani, Amin; Mehrbod, Parvaneh; Haron, Mohd Syamsul Reza; Tan, Sheau Wei; Omar, Abdul Rahman

    2015-11-01

    Apoptosis has been postulated to play an important role during feline infectious peritonitis virus (FIPV) infection; however, its mechanism is not well characterized. This study is focused on apoptosis and transcriptional profiling of FIPV-infected cells following in vitro infection of CRFK cells with FIPV 79-1146 WSU. Flow cytometry was used to determine mode of cell death in first 42 h post infection (hpi). FIPV infected cells underwent early apoptosis at 9 hpi (p < 0.05) followed by late apoptosis at 12 hpi (p < 0.05) and necrosis from 24 hpi (p < 0.05). Then, next generation sequencing was performed on 9 hpi and control uninfected cells by Illumina analyzer. An aggregate of 4546 genes (2229 down-regulated and 2317 up-regulated) from 17 cellular process, 11 molecular functions and 130 possible biological pathways were affected by FIPV. 131 genes from apoptosis cluster (80 down-regulated and 51 up-regulated) along with increase of apoptosis, p53, p38 MAPK, VEGF and chemokines/cytokines signaling pathways were probably involved in apoptosis process. Six of the de-regulated genes expression (RASSF1, BATF2, MAGEB16, PDCD5, TNFα and TRAF2) and TNFα protein concentration were analyzed by RT-qPCR and ELISA, respectively, at different time-points. Up-regulations of both pro-apoptotic (i.e. PDCD5) and anti-apoptotic (i.e. TRAF2) were detected from first hpi and continuing to deregulate during apoptosis process in the infected cells.

  12. NK cell-like behavior of Valpha14i NK T cells during MCMV infection.

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    Johnna D Wesley

    2008-07-01

    Full Text Available Immunity to the murine cytomegalovirus (MCMV is critically dependent on the innate response for initial containment of viral replication, resolution of active infection, and proper induction of the adaptive phase of the anti-viral response. In contrast to NK cells, the Valpha14 invariant natural killer T cell response to MCMV has not been examined. We found that Valpha14i NK T cells become activated and produce significant levels of IFN-gamma, but do not proliferate or produce IL-4 following MCMV infection. In vivo treatment with an anti-CD1d mAb and adoptive transfer of Valpha14i NK T cells into MCMV-infected CD1d(-/- mice demonstrate that CD1d is dispensable for Valpha14i NK T cell activation. In contrast, both IFN-alpha/beta and IL-12 are required for optimal activation. Valpha14i NK T cell-derived IFN-gamma is partially dependent on IFN-alpha/beta but highly dependent on IL-12. Valpha14i NK T cells contribute to the immune response to MCMV and amplify NK cell-derived IFN-gamma. Importantly, mortality is increased in CD1d(-/- mice in response to high dose MCMV infection when compared to heterozygote littermate controls. Collectively, these findings illustrate the plasticity of Valpha14i NK T cells that act as effector T cells during bacterial infection, but have NK cell-like behavior during the innate immune response to MCMV infection.

  13. HIV infection of monocytes-derived dendritic cells inhibits Vγ9Vδ2 T cells functions.

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    Alessandra Sacchi

    Full Text Available DCs act as sentinel cells against incoming pathogens and represent the most potent antigen presenting cells, having the unique capability to prime naïve T cells. In addition to their role in induction of adaptive immune responses, DC are also able to activate innate cells as γδ T cells; in particular, a reciprocal crosstalk between DC and γδ T cells was demonstrated. However, whether HIV infection may alter DC-Vγ9Vδ2 T cells cross-talk was not yet described. To clarify this issue, we cultured activated Vγ9Vδ2 T cells with HIV infected monocyte derived DC (MoDC. After 5 days we evaluated MoDC phenotype, and Vγ9Vδ2 T cells activation and proliferation. In our model, Vγ9Vδ2 T cells were not able to proliferate in response to HIV-infected MoDC, although an up-regulation of CD69 was observed. Upon phosphoantigens stimulation, Vγ9Vδ2 T cells proliferation and cytokine production were inhibited when cultured with HIV-infected MoDC in a cell-contact dependent way. Moreover, HIV-infected MoDC are not able to up-regulate CD86 molecules when cultured with activated Vγ9Vδ2 T cells, compared with uninfected MoDC. Further, activated Vγ9Vδ2 T cells are not able to induce HLA DR up-regulation and CCR5 down-regulation on HIV-infected MoDC. These data indicate that HIV-infected DC alter the capacity of Vγ9Vδ2 T cells to respond to their antigens, pointing out a new mechanisms of induction of Vγ9Vδ2 T cells anergy carried out by HIV, that could contribute to immune evasion.

  14. HIV infection of monocytes-derived dendritic cells inhibits Vγ9Vδ2 T cells functions.

    Science.gov (United States)

    Sacchi, Alessandra; Rinaldi, Alessandra; Tumino, Nicola; Casetti, Rita; Agrati, Chiara; Turchi, Federica; Bordoni, Veronica; Cimini, Eleonora; Martini, Federico

    2014-01-01

    DCs act as sentinel cells against incoming pathogens and represent the most potent antigen presenting cells, having the unique capability to prime naïve T cells. In addition to their role in induction of adaptive immune responses, DC are also able to activate innate cells as γδ T cells; in particular, a reciprocal crosstalk between DC and γδ T cells was demonstrated. However, whether HIV infection may alter DC-Vγ9Vδ2 T cells cross-talk was not yet described. To clarify this issue, we cultured activated Vγ9Vδ2 T cells with HIV infected monocyte derived DC (MoDC). After 5 days we evaluated MoDC phenotype, and Vγ9Vδ2 T cells activation and proliferation. In our model, Vγ9Vδ2 T cells were not able to proliferate in response to HIV-infected MoDC, although an up-regulation of CD69 was observed. Upon phosphoantigens stimulation, Vγ9Vδ2 T cells proliferation and cytokine production were inhibited when cultured with HIV-infected MoDC in a cell-contact dependent way. Moreover, HIV-infected MoDC are not able to up-regulate CD86 molecules when cultured with activated Vγ9Vδ2 T cells, compared with uninfected MoDC. Further, activated Vγ9Vδ2 T cells are not able to induce HLA DR up-regulation and CCR5 down-regulation on HIV-infected MoDC. These data indicate that HIV-infected DC alter the capacity of Vγ9Vδ2 T cells to respond to their antigens, pointing out a new mechanisms of induction of Vγ9Vδ2 T cells anergy carried out by HIV, that could contribute to immune evasion.

  15. Bioactive molecules released from cells infected with the Human Cytomegalovirus

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    Anna eLuganini

    2016-05-01

    Full Text Available Following primary infection in humans, the Human Cytomegalovirus (HCMV persists in a latent state throughout the host’s lifetime despite a strong and efficient immune response. If the host experiences some form of immune dysregulation, such as immunosuppression or immunodeficiency, HCMV reactivates, thereby emerging from latency. Thus, in the absence of effective functional immune responses, as occurs in immunocompromised or immunoimmature individuals, both HCMV primary infections and reactivations from latency can cause significant morbidity and mortality. However, even in immunocompetent hosts, HCMV represents a relevant risk factor for the development of several chronic inflammatory diseases and certain forms of neoplasia. HCMV infection may shift between the lytic and latent state, regulated by a delicate and intricate balance between virus-mediated immunomodulation and host immune defenses. Indeed, HCMV is a master in manipulating innate and adaptive host defense pathways, and a large portion of its genome is devoted to encoding immunomodulatory proteins; such proteins may thus represent important virulence determinants. However, the pathogenesis of HCMV-related diseases is strengthened by the activities of bioactive molecules, of both viral and cellular origin, that are secreted from infected cells and collectively named as the secretome. Here, we review the state of knowledge on the composition and functions of HCMV-derived secretomes. In lytic infections of fibroblasts and different types of endothelial cells, the majority of HCMV-induced secreted proteins act in a paracrine fashion to stimulate the generation of an inflammatory microenvironment around infected cells; this may lead to vascular inflammation and angiogenesis that, in turn, foster HCMV replication and its dissemination through host tissues. Conversely, the HCMV secretome derived from latently infected hematopoietic progenitor cells induces an immunosuppressive

  16. Creation and characterization of a cell-death reporter cell line for hepatitis C virus infection

    Science.gov (United States)

    Chen, Zhilei; Simeon, Rudo; Chockalingam, Karuppiah; Rice, Charles M.

    2010-01-01

    The present study describes the creation and characterization of a hepatoma cell line, n4mBid, that supports all stages of the hepatitis C virus (HCV) life cycle and strongly reports HCV infection by a cell-death phenotype. The n4mBid cell line is derived from the highly HCV-permissive Huh-7.5 hepatoma cell line and contains a modified Bid protein (mBid) that is cleaved and activated by the HCV serine protease NS3-4A. N4mBid exhibited a 10–20 fold difference in cell viability between the HCV-infected and mock-infected states, while the parental Huh-7.5 cells showed <2 fold difference under the same conditions. The pronounced difference in n4mBid cell viability between the HCV- and mock-infected states in a 96-well plate format points to its usefulness in cell survival-based high-throughput screens for anti-HCV molecules. The degree of cell death was found to be proportional to the intracellular load of HCV. HCV-low n4mBid cells, expressing an anti-HCV short hairpin RNA, showed a significant growth advantage over naïve cells and could be rapidly enriched after HCV infection, suggesting the possibility of using n4mBid cells for the cell survival-based selection of genetic anti-HCV factors. PMID:20188762

  17. Direct infection of dendritic cells during chronic viral infection suppresses antiviral T cell proliferation and induces IL-10 expression in CD4 T cells.

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    Carmen Baca Jones

    Full Text Available Elevated levels of systemic IL-10 have been associated with several chronic viral infections, including HCV, EBV, HCMV and LCMV. In the chronic LCMV infection model, both elevated IL-10 and enhanced infection of dendritic cells (DCs are important for viral persistence. This report highlights the relationship between enhanced viral tropism for DCs and the induction of IL-10 in CD4 T cells, which we identify as the most frequent IL-10-expressing cell type in chronic LCMV infection. Here we report that infected CD8αneg DCs express elevated IL-10, induce IL-10 expression in LCMV specific CD4 T cells, and suppress LCMV-specific T cell proliferation. DCs exposed in vivo to persistent LCMV retain the capacity to stimulate CD4 T cell proliferation but induce IL-10 production by both polyclonal and LCMV-specific CD4 T cells. Our study delineates the unique effects of direct infection versus viral exposure on DCs. Collectively these data point to enhanced infection of DCs as a key trigger of the IL-10 induction cascade resulting in maintenance of elevated IL-10 expression in CD4 T cells and inhibition of LCMV-specific CD4 and CD8 T cell proliferation.

  18. Mesenchymal stem cell derived hematopoietic cells are permissive to HIV-1 infection

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    Mondal Debasis

    2011-01-01

    Full Text Available Abstract Background Tissue resident mesenchymal stem cells (MSCs are multipotent, self-renewing cells known for their differentiation potential into cells of mesenchymal lineage. The ability of single cell clones isolated from adipose tissue resident MSCs (ASCs to differentiate into cells of hematopoietic lineage has been previously demonstrated. In the present study, we investigated if the hematopoietic differentiated (HD cells derived from ASCs could productively be infected with HIV-1. Results HD cells were generated by differentiating clonally expanded cultures of adherent subsets of ASCs (CD90+, CD105+, CD45-, and CD34-. Transcriptome analysis revealed that HD cells acquire a number of elements that increase their susceptibility for HIV-1 infection, including HIV-1 receptor/co-receptor and other key cellular cofactors. HIV-1 infected HD cells (HD-HIV showed elevated p24 protein and gag and tat gene expression, implying a high and productive infection. HD-HIV cells showed decreased CD4, but significant increase in the expression of CCR5, CXCR4, Nef-associated factor HCK, and Vpu-associated factor BTRC. HIV-1 restricting factors like APOBEC3F and TRIM5 also showed up regulation. HIV-1 infection increased apoptosis and cell cycle regulatory genes in HD cells. Although undifferentiated ASCs failed to show productive infection, HIV-1 exposure increased the expression of several hematopoietic lineage associated genes such as c-Kit, MMD2, and IL-10. Conclusions Considering the presence of profuse amounts of ASCs in different tissues, these findings suggest the possible role that could be played by HD cells derived from ASCs in HIV-1 infection. The undifferentiated ASCs were non-permissive to HIV-1 infection; however, HIV-1 exposure increased the expression of some hematopoietic lineage related genes. The findings relate the importance of ASCs in HIV-1 research and facilitate the understanding of the disease process and management strategies.

  19. Protective role of Th17 cells in pulmonary infection.

    Science.gov (United States)

    Rathore, Jitendra Singh; Wang, Yan

    2016-03-18

    Th17 cells are characterized as preferential producer of interleukins including IL-17A, IL-17F, IL-21 and IL-22. Corresponding receptors of these cytokines are expressed on number of cell types found in the mucosa, including epithelial cells and fibroblasts which constitute the prime targets of the Th17-associated cytokines. Binding of IL-17 family members to their corresponding receptors lead to modulation of antimicrobial functions of target cells including alveolar epithelial cells. Stimulated alveolar epithelial cells produce antimicrobial peptides and are involved in granulepoesis, neutrophil recruitment and tissue repair. Mucosal immunity mediated by Th17 cells is protective against numerous pulmonary pathogens including extracellular bacterial and fungal pathogens. This review focuses on the protective role of Th17 cells during pulmonary infection, highlighting subset differentiation, effector cytokines production, followed by study of the binding of these cytokines to their corresponding receptors, the subsequent signaling pathway they engender and their effector role in host defense.

  20. Regulatory T cells and the immune pathogenesis of prenatal infection.

    Science.gov (United States)

    Rowe, Jared H; Ertelt, James M; Xin, Lijun; Way, Sing Sing

    2013-12-01

    Pregnancy in placental mammals offers exceptional comprehensive benefits of in utero protection, nutrition, and metabolic waste elimination for the developing fetus. However, these benefits also require durable strategies to mitigate maternal rejection of fetal tissues expressing foreign paternal antigens. Since the initial postulate of expanded maternal immune tolerance by Sir Peter Medawar 60 years ago, an amazingly elaborate assortment of molecular and cellular modifications acting both locally at the maternal-placental interface and systemically have been shown to silence potentially detrimental maternal immune responses. In turn, simultaneously maintaining host defense against the infinite array of potential pathogens during pregnancy is equally important. Fortunately, resistance against most infections is preserved seamlessly throughout gestation. On the other hand, recent studies on pathogens with unique predisposition for prenatal infections have uncovered distinctive holes in host defense associated with the reproductive process. Using these infections to probe the response during pregnancy, the immune suppressive regulatory subset of maternal CD4 T cells has been increasingly shown to dictate the inter-workings between prenatal infection susceptibility and pathogenesis of ensuing pregnancy complications. Herein, the recent literature suggesting a necessity for maternal regulatory T cells (Tregs) in pregnancy-induced immunological shifts that sustain fetal tolerance is reviewed. Additional discussion is focused on how expansion of maternal Treg suppression may become exploited by pathogens that cause prenatal infections and the perilous potential of infection-induced immune activation that may mitigate fetal tolerance and inadvertently inject hostility into the protective in utero environment.

  1. Innate immune control of EBV-infected B cells by invariant natural killer T cells.

    Science.gov (United States)

    Chung, Brian K; Tsai, Kevin; Allan, Lenka L; Zheng, Dong Jun; Nie, Johnny C; Biggs, Catherine M; Hasan, Mohammad R; Kozak, Frederick K; van den Elzen, Peter; Priatel, John J; Tan, Rusung

    2013-10-10

    Individuals with X-linked lymphoproliferative disease lack invariant natural killer T (iNKT) cells and are exquisitely susceptible to Epstein-Barr virus (EBV) infection. To determine whether iNKT cells recognize or regulate EBV, resting B cells were infected with EBV in the presence or absence of iNKT cells. The depletion of iNKT cells increased both viral titers and the frequency of EBV-infected B cells. However, EBV-infected B cells rapidly lost expression of the iNKT cell receptor ligand CD1d, abrogating iNKT cell recognition. To determine whether induced CD1d expression could restore iNKT recognition in EBV-infected cells, lymphoblastoid cell lines (LCL) were treated with AM580, a synthetic retinoic acid receptor-α agonist that upregulates CD1d expression via the nuclear protein, lymphoid enhancer-binding factor 1 (LEF-1). AM580 significantly reduced LEF-1 association at the CD1d promoter region, induced CD1d expression on LCL, and restored iNKT recognition of LCL. CD1d-expressing LCL elicited interferon γ secretion and cytotoxicity by iNKT cells even in the absence of exogenous antigen, suggesting an endogenous iNKT antigen is expressed during EBV infection. These data indicate that iNKT cells may be important for early, innate control of B cell infection by EBV and that downregulation of CD1d may allow EBV to circumvent iNKT cell-mediated immune recognition.

  2. Effect of the purinergic receptor P2X7 on Chlamydia infection in cervical epithelial cells and vaginally infected mice.

    Science.gov (United States)

    Darville, Toni; Welter-Stahl, Lynn; Cruz, Cristiane; Sater, Ali Abdul; Andrews, Charles W; Ojcius, David M

    2007-09-15

    Ligation of the purinergic receptor, P2X7R, with its agonist ATP has been previously shown to inhibit intracellular infection by chlamydiae and mycobacteria in macrophages. The effect of P2X7R on chlamydial infection had never been investigated in the preferred target cells of chlamydiae, cervical epithelial cells, nor in vaginally infected mice. In this study, we show that treatment of epithelial cells with P2X7R agonists inhibits partially Chlamydia infection in epithelial cells. Chelation of ATP with magnesium or pretreatment with a P2X7R antagonist blocks the inhibitory effects of ATP. Similarly to previous results obtained with macrophages, ATP-mediated inhibition of infection in epithelial cells requires activation of host-cell phospholipase D. Vaginal infection was also more efficient in P2X7R-deficient mice, which also displayed a higher level of acute inflammation in the endocervix, oviduct, and mesosalpingeal tissues than in infected wild-type mice. However, secretion of IL-1beta, which requires P2X7R ligation during infection by other pathogens, was decreased mildly and only at short times of infection. Taken together, these results suggest that P2X7R affects Chlamydia infection by directly inhibiting infection in epithelial cells, rather than through the ability of P2X7R to modulate IL-1beta secretion.

  3. γδ T cells in infection and autoimmunity.

    Science.gov (United States)

    Hou, Lifei; Wang, Tian; Sun, Jiaren

    2015-10-01

    Standing at the interface of innate and adaptive immune, γδ T cells play important pathophysiologic roles in infection, autoimmunity, and tumorigenesis. Recent studies indicate that γδ T cells could be categorized into IFN-γ(+) and IL-17(+) subsets, both of which possess select TCR usages, bear unique surface markers and require different cytokine signaling to maintain the homeostasis. In addition, as the major innate IL-17 producers, γδ T cells are increasingly appreciated for their involvement in various acute infections and injuries. This review will summarize the characteristics of IFN-γ(+) (γδ T-IFN-γ) and IL-17(+) γδ T cells (γδT17) and discuss their distinct pathogenic functions in different disease models.

  4. Proteomic profile of human monocytic cells infected with dengue virus

    Institute of Scientific and Technical Information of China (English)

    Viviana Martnez-Betancur; Marlen Martnez-Gutierrez

    2016-01-01

    Objective: To identify the changes in the proteome of U937 cells infected with dengue virus (DENV). Methods: In this study, differentiated U937 cultures were infected with two DENV-2 strains, one of which was associated with dengue (DENV-2/NG) and the other one with severe dengue (DENV-2/16681), with the aim of determining the cellular proteomic profiles under different infection conditions. Cellular proteins were extracted and sepa-rated by two-dimensional electrophoresis, and those proteins with differential expression profiles were identified by mass spectrometry. The obtained results were correlated with cellular viability, the number of infectious viral particles, and the viral DNA/protein quantity. Results: In comparison with non-infected cultures, in the cells infected with the DENV-2/NG strain, nine proteins were expressed differentially (five were upregulated and four were downregulated); in those cultures infected with the DENV-2/16681 strain, six proteins were differentially expressed (two were downregulated and four were upregu-lated). The downregulated proteins included fatty acid-binding protein, heterogeneous nuclear ribonucleoprotein 1, protein disulfide isomerase, enolase 1, heat shock 70 kDa protein 9, phosphotyrosyl phosphatase, and annexin IV. The upregulated proteins included heat shock 90 kDa protein AA1, tubulin beta, enolase 1, pyruvate kinase, transaldolase and phospholipase C-alpha. Conclusions: Because the monocyte/macrophage lineage is critical for disease patho-genicity, additional studies on these proteins could provide a better understanding of the cellular response to DENV infection and could help identify new therapeutic targets against infection.

  5. Helicobacter pylori impairs murine dendritic cell responses to infection.

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    Ya-Hui Wang

    Full Text Available BACKGROUND: Helicobacter pylori, a human pathogen associated with chronic gastritis, peptic ulcer and gastric malignancies, is generally viewed as an extracellular microorganism. Here, we show that H. pylori replicates in murine bone marrow derived-dendritic cells (BMDCs within autophagosomes. METHODOLOGY/PRINCIPAL FINDINGS: A 10-fold increase of CFU is found between 2 h and 6 h p.i. in H. pylori-infected BMDCs. Autophagy is induced around the bacterium and participates at late time points of infection for the clearance of intracellular H. pylori. As a consequence of infection, LC3, LAMP1 and MHC class II molecules are retained within the H. pylori-containing vacuoles and export of MHC class II molecules to cell surface is blocked. However, formalin-fixed H. pylori still maintain this inhibitory activity in BMDC derived from wild type mice, but not in from either TLR4 or TLR2-deficient mice, suggesting the involvement of H. pylori-LPS in this process. TNF-alpha, IL-6 and IL-10 expression was also modulated upon infection showing a TLR2-specific dependent IL-10 secretion. No IL-12 was detected favoring the hypothesis of a down modulation of DC functions during H. pylori infection. Furthermore, antigen-specific T cells proliferation was also impaired upon infection. CONCLUSIONS/SIGNIFICANCE: H. pylori can infect and replicate in BMDCs and thereby affects DC-mediated immune responses. The implication of this new finding is discussed for the biological life cycle of H. pylori in the host.

  6. Modulation of respiratory dendritic cells during Klebsiella pneumonia infection

    OpenAIRE

    Hackstein, Holger; Kranz, Sabine; Lippitsch, Anne; Wachtendorf, Andreas; Kershaw, Olivia; Achim D Gruber; Michel, Gabriela; Lohmeyer, Jürgen; Bein, Gregor; Baal, Nelli; Herold, Susanne

    2013-01-01

    Background: Klebsiella pneumoniae is a leading cause of severe hospital-acquired respiratory tract infections and death but little is known regarding the modulation of respiratory dendritic cell (DC) subsets. Plasmacytoid DC (pDC) are specialized type 1 interferon producing cells and considered to be classical mediators of antiviral immunity. Method: By using multiparameter flow cytometry analysis we have analysed the modulation of respiratory DC subsets after intratracheal Klebsi...

  7. HIV-1 Trans Infection of CD4+ T Cells by Professional Antigen Presenting Cells

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    Charles R. Rinaldo

    2013-01-01

    Full Text Available Since the 1990s we have known of the fascinating ability of a complex set of professional antigen presenting cells (APCs; dendritic cells, monocytes/macrophages, and B lymphocytes to mediate HIV-1 trans infection of CD4+ T cells. This results in a burst of virus replication in the T cells that is much greater than that resulting from direct, cis infection of either APC or T cells, or trans infection between T cells. Such APC-to-T cell trans infection first involves a complex set of virus subtype, attachment, entry, and replication patterns that have many similarities among APC, as well as distinct differences related to virus receptors, intracellular trafficking, and productive and nonproductive replication pathways. The end result is that HIV-1 can sequester within the APC for several days and be transmitted via membrane extensions intracellularly and extracellularly to T cells across the virologic synapse. Virus replication requires activated T cells that can develop concurrently with the events of virus transmission. Further research is essential to fill the many gaps in our understanding of these trans infection processes and their role in natural HIV-1 infection.

  8. Cell differentiation defines acute and chronic infection cell types in Staphylococcus aureus.

    Science.gov (United States)

    García-Betancur, Juan-Carlos; Goñi-Moreno, Angel; Horger, Thomas; Schott, Melanie; Sharan, Malvika; Eikmeier, Julian; Wohlmuth, Barbara; Zernecke, Alma; Ohlsen, Knut; Kuttler, Christina; Lopez, Daniel

    2017-09-12

    A central question to biology is how pathogenic bacteria initiate acute or chronic infections. Here we describe a genetic program for cell-fate decision in the opportunistic human pathogen Staphylococcus aureus, which generates the phenotypic bifurcation of the cells into two genetically identical but different cell types during the course of an infection. Whereas one cell type promotes the formation of biofilms that contribute to chronic infections, the second type is planktonic and produces the toxins that contribute to acute bacteremia. We identified a bimodal switch in the agr quorum sensing system that antagonistically regulates the differentiation of these two physiologically distinct cell types. We found that extracellular signals affect the behavior of the agr bimodal switch and modify the size of the specialized subpopulations in specific colonization niches. For instance, magnesium-enriched colonization niches causes magnesium binding to S. aureusteichoic acids and increases bacterial cell wall rigidity. This signal triggers a genetic program that ultimately downregulates the agr bimodal switch. Colonization niches with different magnesium concentrations influence the bimodal system activity, which defines a distinct ratio between these subpopulations; this in turn leads to distinct infection outcomes in vitro and in an in vivo murine infection model. Cell differentiation generates physiological heterogeneity in clonal bacterial infections and helps to determine the distinct infection types.

  9. Human induced pluripotent stem cell-derived models to investigate human cytomegalovirus infection in neural cells.

    Directory of Open Access Journals (Sweden)

    Leonardo D'Aiuto

    Full Text Available Human cytomegalovirus (HCMV infection is one of the leading prenatal causes of congenital mental retardation and deformities world-wide. Access to cultured human neuronal lineages, necessary to understand the species specific pathogenic effects of HCMV, has been limited by difficulties in sustaining primary human neuronal cultures. Human induced pluripotent stem (iPS cells now provide an opportunity for such research. We derived iPS cells from human adult fibroblasts and induced neural lineages to investigate their susceptibility to infection with HCMV strain Ad169. Analysis of iPS cells, iPS-derived neural stem cells (NSCs, neural progenitor cells (NPCs and neurons suggests that (i iPS cells are not permissive to HCMV infection, i.e., they do not permit a full viral replication cycle; (ii Neural stem cells have impaired differentiation when infected by HCMV; (iii NPCs are fully permissive for HCMV infection; altered expression of genes related to neural metabolism or neuronal differentiation is also observed; (iv most iPS-derived neurons are not permissive to HCMV infection; and (v infected neurons have impaired calcium influx in response to glutamate.

  10. Cell differentiation defines acute and chronic infection cell types in Staphylococcus aureus

    Science.gov (United States)

    García-Betancur, Juan-Carlos; Goñi-Moreno, Angel; Horger, Thomas; Schott, Melanie; Sharan, Malvika; Eikmeier, Julian; Wohlmuth, Barbara; Zernecke, Alma; Ohlsen, Knut; Kuttler, Christina

    2017-01-01

    A central question to biology is how pathogenic bacteria initiate acute or chronic infections. Here we describe a genetic program for cell-fate decision in the opportunistic human pathogen Staphylococcus aureus, which generates the phenotypic bifurcation of the cells into two genetically identical but different cell types during the course of an infection. Whereas one cell type promotes the formation of biofilms that contribute to chronic infections, the second type is planktonic and produces the toxins that contribute to acute bacteremia. We identified a bimodal switch in the agr quorum sensing system that antagonistically regulates the differentiation of these two physiologically distinct cell types. We found that extracellular signals affect the behavior of the agr bimodal switch and modify the size of the specialized subpopulations in specific colonization niches. For instance, magnesium-enriched colonization niches causes magnesium binding to S. aureusteichoic acids and increases bacterial cell wall rigidity. This signal triggers a genetic program that ultimately downregulates the agr bimodal switch. Colonization niches with different magnesium concentrations influence the bimodal system activity, which defines a distinct ratio between these subpopulations; this in turn leads to distinct infection outcomes in vitro and in an in vivo murine infection model. Cell differentiation generates physiological heterogeneity in clonal bacterial infections and helps to determine the distinct infection types. PMID:28893374

  11. Regulatory T Cells in Chronic Hepatitis B Virus Infection

    NARCIS (Netherlands)

    J.N. Stoop (Jeroen Nicolaas)

    2007-01-01

    textabstractWorldwide 400 million people suffer from chronic hepatitis B virus (HBV) infection and approximately 1 million people die annually from HBV-related disease. To clear HBV, an effective immune response, in which several cell types and cytokines play a role, is important. It is known that p

  12. Phospholipid Synthesis in Sindbis Virus-Infected Cells

    Science.gov (United States)

    Waite, Marilynn R. F.; Pfefferkorn, E. R.

    1970-01-01

    We investigated the metabolic requirements for the decrease in phospholipid synthesis previously observed by Pfefferkorn and Hunter in primary cultures of chick embryo fibroblasts infected with Sindbis virus. The incorporation of 32PO4 into all classes of phospholipids was found to decline at the same rate and to the same extent; thus, incorporation of 14C-choline into acid-precipitable form provided a convenient measure of phospholipid synthesis that was used in subsequent experiments. Experiments with temperature-sensitive mutants suggested that some viral ribonucleic acid (RNA) synthesis was essential for the inhibition of choline incorporation, but that functional viral structural proteins were not required. The reduction in phospholipid synthesis was probably a secondary effect of infection resulting from viral inhibition of the cellular RNA and protein synthesis. All three inhibitory effects required about the same amount of viral RNA synthesis; the inhibition of host RNA and protein synthesis began sooner than the decline in phospholipid synthesis; and both actinomycin D and cycloheximide inhibited 14C-choline incorporation in uninfected cells. In contrast, incorporation of 14C-choline into BHK-21 cells was not decreased by 10 hr of exposure to actinomycin D and declined only slowly after cycloheximide treatment. Growth of Sindbis virus in BHK cells did not cause the marked stimulation of phospholipid synthesis seen in picornavirus infections of other mammalian cells; however, inhibition was seen only late in infection. PMID:5530011

  13. Early Trypanosoma cruzi Infection Reprograms Human Epithelial Cells

    Directory of Open Access Journals (Sweden)

    María Laura Chiribao

    2014-01-01

    Full Text Available Trypanosoma cruzi, the causative agent of Chagas disease, has the peculiarity, when compared with other intracellular parasites, that it is able to invade almost any type of cell. This property makes Chagas a complex parasitic disease in terms of prophylaxis and therapeutics. The identification of key host cellular factors that play a role in the T. cruzi invasion is important for the understanding of disease pathogenesis. In Chagas disease, most of the focus is on the response of macrophages and cardiomyocytes, since they are responsible for host defenses and cardiac lesions, respectively. In the present work, we studied the early response to infection of T. cruzi in human epithelial cells, which constitute the first barrier for establishment of infection. These studies identified up to 1700 significantly altered genes regulated by the immediate infection. The global analysis indicates that cells are literally reprogrammed by T. cruzi, which affects cellular stress responses (neutrophil chemotaxis, DNA damage response, a great number of transcription factors (including the majority of NFκB family members, and host metabolism (cholesterol, fatty acids, and phospholipids. These results raise the possibility that early host cell reprogramming is exploited by the parasite to establish the initial infection and posterior systemic dissemination.

  14. Understanding the T cell immune response in SARS coronavirus infection.

    Science.gov (United States)

    Janice Oh, Hsueh-Ling; Ken-En Gan, Samuel; Bertoletti, Antonio; Tan, Yee-Joo

    2012-09-01

    The severe acute respiratory syndrome (SARS) epidemic started in late 2002 and swiftly spread across 5 continents with a mortality rate of around 10%. Although the epidemic was eventually controlled through the implementation of strict quarantine measures, there continues a need to investigate the SARS coronavirus (SARS-CoV) and develop interventions should it re-emerge. Numerous studies have shown that neutralizing antibodies against the virus can be found in patients infected with SARS-CoV within days upon the onset of illness and lasting up to several months. In contrast, there is little data on the kinetics of T cell responses during SARS-CoV infection and little is known about their role in the recovery process. However, recent studies in mice suggest the importance of T cells in viral clearance during SARS-CoV infection. Moreover, a growing number of studies have investigated the memory T cell responses in recovered SARS patients. This review covers the available literature on the emerging importance of T cell responses in SARS-CoV infection, particularly on the mapping of cytotoxic T lymphocyte (CTL) epitopes, longevity, polyfunctionality and human leukocyte antigen (HLA) association as well as their potential implications on treatment and vaccine development.

  15. Human skin Langerhans cells are targets of dengue virus infection

    NARCIS (Netherlands)

    Wu, SJL; Grouard-Vogel, G; Mascola, [No Value; Brachtel, E; Putvatana, R; Louder, MK; Filgueira, L; Marovich, MA; Wong, HK; Blauvelt, A; Murphy, GS; Robb, ML; Innes, BL; Birx, DL; Hayes, CG; Frankel, SS

    2000-01-01

    Dengue virus (DV), an arthropod-borne flavivirus, causes a febrile illness for which there is no antiviral treatment and no vaccine(1,2). Macrophages are important in dengue pathogenesis; however, the initial target cell for DV infection remains unknown. As DV is introduced into human skin by mosqui

  16. Target cell cyclophilins facilitate human papillomavirus type 16 infection.

    Directory of Open Access Journals (Sweden)

    Malgorzata Bienkowska-Haba

    2009-07-01

    Full Text Available Following attachment to primary receptor heparan sulfate proteoglycans (HSPG, human papillomavirus type 16 (HPV16 particles undergo conformational changes affecting the major and minor capsid proteins, L1 and L2, respectively. This results in exposure of the L2 N-terminus, transfer to uptake receptors, and infectious internalization. Here, we report that target cell cyclophilins, peptidyl-prolyl cis/trans isomerases, are required for efficient HPV16 infection. Cell surface cyclophilin B (CyPB facilitates conformational changes in capsid proteins, resulting in exposure of the L2 N-terminus. Inhibition of CyPB blocked HPV16 infection by inducing noninfectious internalization. Mutation of a putative CyP binding site present in HPV16 L2 yielded exposed L2 N-terminus in the absence of active CyP and bypassed the need for cell surface CyPB. However, this mutant was still sensitive to CyP inhibition and required CyP for completion of infection, probably after internalization. Taken together, these data suggest that CyP is required during two distinct steps of HPV16 infection. Identification of cell surface CyPB will facilitate the study of the complex events preceding internalization and adds a putative drug target for prevention of HPV-induced diseases.

  17. Agglutination of Trypanosoma cruzi in infected cells treated with serum from chronically infected mice.

    Science.gov (United States)

    Wendelken, Jennifer L; Rowland, Edwin C

    2009-04-01

    The protozoan parasite Trypanosoma cruzi is the causative agent of Chagas disease. The chronic stage of infection is characterized by a production of neutralizing antibodies in the vertebrate host. A polyclonal antibody, anti-egressin, has been found to inhibit egress of parasites from the host cell late in the intracellular cycle, after the parasites have transformed from the replicative amastigote into the trypomastigote. It has also been found that BALB/c mouse fibroblasts in the late stages of parasite infection become permeable to molecules as large as antibodies, leading to the possibility that anti-egressin affects the intracellular parasites. This project addresses the fate of the intracellular trypomastigotes that have been inhibited from egressing the host cell. Extended cultures of infected fibroblasts treated with chronic mouse serum reduced parasite egress at all time points measured. Parasites released from infected fibroblasts treated with chronic serum had a reduced ability to infect fibroblasts in culture, yet did not lose infectivity entirely. Absorption of chronic serum with living trypomastigotes removed the anti-egressin effect. The possibility that the target of anti-egressin is a parasite surface component is further indicated by the agglutination of extracellular trypomastigotes by chronic serum. The possibility that cross-linking by antibody occurs intracellularly, thus inhibiting egress, was reinforced by cleaving purified IgG into Fab fragments, which did not inhibit egress when added to infected cultures. From this work, it is proposed that the current, best explanation of the mechanism of egress inhibition by anti-egressin is intracellular agglutination, preventing normal parasite-driven egress.

  18. An evaluation of the inhibitory effects against rotavirus infection of edible plant extracts

    Directory of Open Access Journals (Sweden)

    Knipping Karen

    2012-07-01

    Full Text Available Abstract Background Rotaviruses are the single most important cause of severe diarrhea in young children worldwide. The developments of specific, potent and accessible antiviral treatments that restrain rotavirus infection remain important to control rotavirus disease. Methods 150 plant extracts with nutritional applications were screened in vitro on MA-104 cells for their antiviral activity against rhesus rotavirus (RRV. One extract (Aspalathus linearis (Burm.f. R.Dahlgren was also tested for its effect on the loss of transepithelial resistance (TER of Caco-2 cells caused by simian rotavirus (SA-11 infection. Results Aqueous extracts of Nelumbo nucifera Gaertn. fruit, Urtica dioica L. root, Aspalathus linearis (Burm.f. R.Dahlgren leaves, Glycyrrhiza glabra L. root and Olea europaea L. leaves were found to have strong significant antiviral activity with a 50% inhibitory concentration (IC50 Glycyrrhiza glabra was found to have the strongest antiviral activity (IC50 46 μM, followed by luteolin and vitexin from Aspalathus linearis (IC50 respectively 116 μM and 129 μM and apigenin-7-O-glucoside from Melissa officinalis (IC50 150 μM. A combination of Glycyrrhiza glabra L. + Nelumbo nucifera Gaertn. and Urtica dioica L. + Nelumbo nucifera Gaertn. showed synergy in their anti-viral activities. Aspalathus linearis (Burm.f. R.Dahlgren showed no positive effect on the maintenance of the TER. Conclusions These results indicate that nutritional intervention with extracts of Nelumbo nucifera Gaertn., Aspalathus linearis (Burm.f. R.Dahlgren, Urtica dioica L., Glycyrrhiza glabra L. and Olea europaea L. might be useful in the treatment of diarrhea caused by rotavirus infection.

  19. Dynamic Imaging of CD8(+) T cells and dendritic cells during infection with Toxoplasma gondii.

    Science.gov (United States)

    John, Beena; Harris, Tajie H; Tait, Elia D; Wilson, Emma H; Gregg, Beth; Ng, Lai Guan; Mrass, Paulus; Roos, David S; Dzierszinski, Florence; Weninger, Wolfgang; Hunter, Christopher A

    2009-07-01

    To better understand the initiation of CD8(+) T cell responses during infection, the primary response to the intracellular parasite Toxoplasma gondii was characterized using 2-photon microscopy combined with an experimental system that allowed visualization of dendritic cells (DCs) and parasite specific CD8(+) T cells. Infection with T. gondii induced localization of both these populations to the sub-capsular/interfollicular region of the draining lymph node and DCs were required for the expansion of the T cells. Consistent with current models, in the presence of cognate antigen, the average velocity of CD8(+) T cells decreased. Unexpectedly, infection also resulted in modulation of the behavior of non-parasite specific T cells. This TCR-independent process correlated with the re-modeling of the lymph node micro-architecture and changes in expression of CCL21 and CCL3. Infection also resulted in sustained interactions between the DCs and CD8(+) T cells that were visualized only in the presence of cognate antigen and were limited to an early phase in the response. Infected DCs were rare within the lymph node during this time frame; however, DCs presenting the cognate antigen were detected. Together, these data provide novel insights into the earliest interaction between DCs and CD8(+) T cells and suggest that cross presentation by bystander DCs rather than infected DCs is an important route of antigen presentation during toxoplasmosis.

  20. Dynamic Imaging of CD8(+ T cells and dendritic cells during infection with Toxoplasma gondii.

    Directory of Open Access Journals (Sweden)

    Beena John

    2009-07-01

    Full Text Available To better understand the initiation of CD8(+ T cell responses during infection, the primary response to the intracellular parasite Toxoplasma gondii was characterized using 2-photon microscopy combined with an experimental system that allowed visualization of dendritic cells (DCs and parasite specific CD8(+ T cells. Infection with T. gondii induced localization of both these populations to the sub-capsular/interfollicular region of the draining lymph node and DCs were required for the expansion of the T cells. Consistent with current models, in the presence of cognate antigen, the average velocity of CD8(+ T cells decreased. Unexpectedly, infection also resulted in modulation of the behavior of non-parasite specific T cells. This TCR-independent process correlated with the re-modeling of the lymph node micro-architecture and changes in expression of CCL21 and CCL3. Infection also resulted in sustained interactions between the DCs and CD8(+ T cells that were visualized only in the presence of cognate antigen and were limited to an early phase in the response. Infected DCs were rare within the lymph node during this time frame; however, DCs presenting the cognate antigen were detected. Together, these data provide novel insights into the earliest interaction between DCs and CD8(+ T cells and suggest that cross presentation by bystander DCs rather than infected DCs is an important route of antigen presentation during toxoplasmosis.

  1. Comparative efficiency of HIV-1-infected T cell killing by NK cells, monocytes and neutrophils.

    Science.gov (United States)

    Smalls-Mantey, Adjoa; Connors, Mark; Sattentau, Quentin J

    2013-01-01

    HIV-1 infected cells are eliminated in infected individuals by a variety of cellular mechanisms, the best characterized of which are cytotoxic T cell and NK cell-mediated killing. An additional antiviral mechanism is antibody-dependent cellular cytotoxicity. Here we use primary CD4(+) T cells infected with the BaL clone of HIV-1 as target cells and autologous NK cells, monocytes, and neutrophils as effector cells, to quantify the cytotoxicity mediated by the different effectors. This was carried out in the presence or absence of HIV-1-specific antiserum to assess antibody-dependent cellular cytotoxicity. We show that at the same effector to target ratio, NK cells and monocytes mediate similar levels of both antibody-dependent and antibody-independent killing of HIV-1-infected T cells. Neutrophils mediated significant antibody-dependent killing of targets, but were less effective than monocytes or NK cells. These data have implications for acquisition and control of HIV-1 in natural infection and in the context of vaccination.

  2. Stretching and relaxation of malaria-infected red blood cells.

    Science.gov (United States)

    Ye, Ting; Phan-Thien, Nhan; Khoo, Boo Cheong; Lim, Chwee Teck

    2013-09-03

    The invasion of red blood cells (RBCs) by malaria parasites is a complex dynamic process, in which the infected RBCs gradually lose their deformability and their ability to recover their original shape is greatly reduced with the maturation of the parasites. In this work, we developed two types of cell model, one with an included parasite, and the other without an included parasite. The former is a representation of real malaria-infected RBCs, in which the parasite is treated as a rigid body. In the latter, where the parasite is absent, the membrane modulus and viscosity are elevated so as to produce the same features present in the parasite model. In both cases, the cell membrane is modeled as a viscoelastic triangular network connected by wormlike chains. We studied the transient behaviors of stretching deformation and shape relaxation of malaria-infected RBCs based on these two models and found that both models can generate results in agreement with those of previously published studies. With the parasite maturation, the shape deformation becomes smaller and smaller due to increasing cell rigidity, whereas the shape relaxation time becomes longer and longer due to the cell's reduced ability to recover its original shape.

  3. Differential proteome analysis of chikungunya virus infection on host cells.

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    Christina Li-Ping Thio

    Full Text Available BACKGROUND: Chikungunya virus (CHIKV is an emerging mosquito-borne alphavirus that has caused multiple unprecedented and re-emerging outbreaks in both tropical and temperate countries. Despite ongoing research efforts, the underlying factors involved in facilitating CHIKV replication during early infection remains ill-characterized. The present study serves to identify host proteins modulated in response to early CHIKV infection using a proteomics approach. METHODOLOGY AND PRINCIPAL FINDINGS: The whole cell proteome profiles of CHIKV-infected and mock control WRL-68 cells were compared and analyzed using two-dimensional gel electrophoresis (2-DGE. Fifty-three spots were found to be differentially modulated and 50 were successfully identified by MALDI-TOF/TOF. Eight were significantly up-regulated and 42 were down-regulated. The mRNA expressions of 15 genes were also found to correlate with the corresponding protein expression. STRING network analysis identified several biological processes to be affected, including mRNA processing, translation, energy production and cellular metabolism, ubiquitin-proteasome pathway (UPP and cell cycle regulation. CONCLUSION/SIGNIFICANCE: This study constitutes a first attempt to investigate alteration of the host cellular proteome during early CHIKV infection. Our proteomics data showed that during early infection, CHIKV affected the expression of proteins that are involved in mRNA processing, host metabolic machinery, UPP, and cyclin-dependent kinase 1 (CDK1 regulation (in favour of virus survival, replication and transmission. While results from this study complement the proteomics results obtained from previous late host response studies, functional characterization of these proteins is warranted to reinforce our understanding of their roles during early CHIKV infection in humans.

  4. Beta-interferon inhibits cell infection by Trypanosoma cruzi

    Science.gov (United States)

    Kierszenbaum, F.; Sonnenfeld, G.

    1984-01-01

    Beta interferon has been shown to inhibit the capacity of bloodstream forms of the flagellate Trypanosoma cruzi, the causative agent of Chagas' disease, to associate with and infect mouse peritoneal macrophages and rat heart myoblasts. The inhibitory effect was abrogated in the presence of specific antibodies to the interferon. Pretreatment of the parasites with interferon reduced their infectivity for untreated host cells, whereas pretreament of either type of host cell did not affect the interaction. The effect of interferon on the trypanosomes was reversible; the extent of the inhibitory effect was significantly reduced afer 20 min, and was undetectable after 60 min when macrophages were used as host cells. For the myoblasts, 60 min elapsed before the inhibitory effect began to subside and 120 min elapsed before it became insignificant or undetectable.

  5. Brucella abortus Cell Cycle and Infection Are Coordinated.

    Science.gov (United States)

    De Bolle, Xavier; Crosson, Sean; Matroule, Jean-Yves; Letesson, Jean-Jacques

    2015-12-01

    Brucellae are facultative intracellular pathogens. The recent development of methods and genetically engineered strains allowed the description of cell-cycle progression of Brucella abortus, including unipolar growth and the ordered initiation of chromosomal replication. B. abortus cell-cycle progression is coordinated with intracellular trafficking in the endosomal compartments. Bacteria are first blocked at the G1 stage, growth and chromosome replication being resumed shortly before reaching the intracellular proliferation compartment. The control mechanisms of cell cycle are similar to those reported for the bacterium Caulobacter crescentus, and they are crucial for survival in the host cell. The development of single-cell analyses could also be applied to other bacterial pathogens to investigate their cell-cycle progression during infection.

  6. Changes in HIV RNA and CD4 cell count after acute HCV infection in chronically HIV-infected individuals

    NARCIS (Netherlands)

    Gras, L.; Wolf, F. de; Smit, C.; Prins, M.; Meer, J.T. van der; Vanhommerig, J.W.; Zwinderman, A.H.; Schinkel, J.; Geskus, R.B.; Warris, A.

    2015-01-01

    OBJECTIVE: Little is known about the impact of acute hepatitis C virus (HCV) co-infection on HIV-1 disease progression. We investigated CD4 cell count and HIV RNA concentration changes after HCV infection in individuals chronically infected with HIV-1. METHODS: We selected individuals that had the l

  7. The Gametocytes of Leucocytozoon sabrazesi Infect Chicken Thrombocytes, Not Other Blood Cells.

    Science.gov (United States)

    Zhao, Wenting; Liu, Jianwen; Xu, Ruixue; Zhang, Cui; Pang, Qin; Chen, Xin; Liu, Shengfa; Hong, Lingxian; Yuan, Jing; Li, Xiaotong; Chen, Yixin; Li, Jian; Su, Xin-Zhuan

    2015-01-01

    Leucocytozoon parasites infect a large number of avian hosts, including domestic chicken, and cause significant economical loss to the poultry industry. Although the transmission stages of the parasites were observed in avian blood cells more than a century ago, the specific host cell type(s) that the gametocytes infect remain uncertain. Because all the avian blood cells, including red blood cells (RBCs), are nucleated, and the developing parasites dramatically change the morphology of the infected host cells, it has been difficult to identify Leucocytozoon infected host cell(s). Here we use cell-type specific antibodies to investigate the identities of the host cells infected by Leucocytozoon sabrazesi gametocytes. Anti-RBC antibodies stained RBCs membrane strongly, but not the parasite-infected cells, ruling out the possibility of RBCs being the infected host cells. Antibodies recognizing various leukocytes including heterophils, monocytes, lymphocytes, and macrophages did not stain the infected cells either. Antisera raised against a peptide of the parasite cytochrome B (CYTB) stained parasite-infected cells and some leukocytes, particularly cells with a single round nucleus as well as clear/pale cytoplasm suggestive of thrombocytes. Finally, a monoclonal antibody known to specifically bind chicken thrombocytes also stained the infected cells, confirming that L. sabrazesi gametocytes develop within chicken thrombocytes. The identification of L. sabrazesi infected host cell solves a long unresolved puzzle and provides important information for studying parasite invasion of host cells and for developing reagents to interrupt parasite transmission.

  8. Loss of circulating CD4 T cells with B cell helper function during chronic HIV infection.

    Directory of Open Access Journals (Sweden)

    Kristin L Boswell

    2014-01-01

    Full Text Available The interaction between follicular T helper cells (TFH and B cells in the lymph nodes and spleen has a major impact on the development of antigen-specific B cell responses during infection or vaccination. Recent studies described a functional equivalent of these cells among circulating CD4 T cells, referred to as peripheral TFH cells. Here, we characterize the phenotype and in vitro B cell helper activity of peripheral TFH populations, as well as the effect of HIV infection on these populations. In co-culture experiments we confirmed CXCR5+ cells from HIV-uninfected donors provide help to B cells and more specifically, we identified a CCR7(highCXCR5(highCCR6(highPD-1(high CD4 T cell population that secretes IL-21 and enhances isotype-switched immunoglobulin production. This population is significantly decreased in treatment-naïve, HIV-infected individuals and can be recovered after anti-retroviral therapy. We found impaired immunoglobulin production in co-cultures from HIV-infected individuals and found no correlation between the frequency of peripheral TFH cells and memory B cells, or with neutralization activity in untreated HIV infection in our cohort. Furthermore, we found that within the peripheral TFH population, the expression level of TFH-associated genes more closely resembles a memory, non-TFH population, as opposed to a TFH population. Overall, our data identify a heterogeneous population of circulating CD4 T cells that provides in vitro help to B cells, and challenges the origin of these cells as memory TFH cells.

  9. The Role of NK Cell in T Cell Recruitment in Murine Liver Infected with Adenovirus

    Institute of Scientific and Technical Information of China (English)

    游上游; 艾洪武; 黄巍; 张楚瑜

    2003-01-01

    To study the role of natural killer (NK) cells in T cell recruitment in murine liver infected with virus, mice wereintravenously injected daily with anti-NK1.1+ antibody to deplete NK cells. Lymphocytes in the liver tissue of mice infectedwith type 5 adenovirus depleted in the E1 and E3 regions were assessed by fluorometric activated cell sorting (FACS). Ex-pression of chemokine IP-10 and its receptor CXCR3 mRNA in the liver, hepatic lymphocytes and spleen tissue were examined by reverse transcription polymerase chain reaction (RT-PCR). Serum almfine aminotransferase (ALT) was measured asan indicator of liver injury. It was found that infection of adenovims and anfi-Fas monoclonal antibody (mAb) into mice caused liver injury and high expression of interfemn-γ inducible protein-10 (IP-10) mRNA in the liver. Anfi-NK1.1+ mAb, which was intraperitoneally injected into the mice infected with adenovirus, suppresses T cell recruitment and expression of IP-10 mRNA in the hver. Slighter hver injury was also observed. After vires infection, expression of CXCR3 mRNAin spleen and hver tissue was observed at different time. The results suggested that T cell recruitment was initiated by NKcell dependent chemokine IP-10, which induced activated T cells priming in the spleen to the hver of the mouse. NK cells played a key role in T cell recruitment in the liver of mouse infected with adenovims.

  10. Cell-to-cell spread and massive vacuole formation after Cryptococcus neoformans infection of murine macrophages

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    Casadevall Arturo

    2007-08-01

    Full Text Available Abstract Background The interaction between macrophages and Cryptococcus neoformans (Cn is critical for containing dissemination of this pathogenic yeast. However, Cn can either lyse macrophages or escape from within them through a process known as phagosomal extrusion. Both events result in live extracellular yeasts capable of reproducing and disseminating in the extracellular milieu. Another method of exiting the intracellular confines of cells is through host cell-to-cell transfer of the pathogen, and this commonly occurs with the human immuno-deficiency virus (HIV and CD4+ T cells and macrophages. In this report we have used time-lapse imaging to determine if this occurs with Cn. Results Live imaging of Cryptococcus neoformans interactions with murine macrophages revealed cell-to-cell spread of yeast cells from infected donor cells to uninfected cells. Although this phenomenon was relatively rare its occurrence documents a new capacity for this pathogen to infect adjacent cells without exiting the intracellular space. Cell-to-cell spread appeared to be an actin-dependent process. In addition, we noted that cryptococcal phagosomal extrusion was followed by the formation of massive vacuoles suggesting that intracellular residence is accompanied by long lasting damage to host cells. Conclusion C. neoformans can escape the intracellular confines of macrophages in an actin dependent manner by cell-to-cell transfer of the yeast leading to infection of adjacent cells. In addition, complete extrusion of internalized Cn cells can lead to the formation of a massive vacuole which may be a sign of damage to the host macrophage. These observations document new outcomes for the interaction of C. neoformans with host cells that provide precedents for cell biological effects that may contribute to the pathogenesis of cryptococcal infections.

  11. Impairment of T cell function in parasitic infections.

    Directory of Open Access Journals (Sweden)

    Vasco Rodrigues

    2014-02-01

    Full Text Available In mammals subverted as hosts by protozoan parasites, the latter and/or the agonists they release are detected and processed by sensors displayed by many distinct immune cell lineages, in a tissue(s-dependent context. Focusing on the T lymphocyte lineage, we review our present understanding on its transient or durable functional impairment over the course of the developmental program of the intracellular parasites Leishmania spp., Plasmodium spp., Toxoplasma gondii, and Trypanosoma cruzi in their mammalian hosts. Strategies employed by protozoa to down-regulate T lymphocyte function may act at the initial moment of naïve T cell priming, rendering T cells anergic or unresponsive throughout infection, or later, exhausting T cells due to antigen persistence. Furthermore, by exploiting host feedback mechanisms aimed at maintaining immune homeostasis, parasites can enhance T cell apoptosis. We will discuss how infections with prominent intracellular protozoan parasites lead to a general down-regulation of T cell function through T cell anergy and exhaustion, accompanied by apoptosis, and ultimately allowing pathogen persistence.

  12. Th9 Cells Drive Host Immunity against Gastrointestinal Worm Infection.

    Science.gov (United States)

    Licona-Limón, Paula; Henao-Mejia, Jorge; Temann, Angela U; Gagliani, Nicola; Licona-Limón, Ileana; Ishigame, Harumichi; Hao, Liming; Herbert, De'broski R; Flavell, Richard A

    2013-10-17

    Type 2 inflammatory cytokines, including interleukin-4 (IL-4), IL-5, IL-9, and IL-13, drive the characteristic features of immunity against parasitic worms and allergens. Whether IL-9 serves an essential role in the initiation of host-protective responses is controversial, and the importance of IL-9- versus IL-4-producing CD4⁺ effector T cells in type 2 immunity is incompletely defined. Herein, we generated IL-9-deficient and IL-9-fluorescent reporter mice that demonstrated an essential role for this cytokine in the early type 2 immunity against Nippostrongylus brasiliensis. Whereas T helper 9 (Th9) cells and type 2 innate lymphoid cells (ILC2s) were major sources of infection-induced IL-9 production, the adoptive transfer of Th9 cells, but not Th2 cells, caused rapid worm expulsion, marked basophilia, and increased mast cell numbers in Rag2-deficient hosts. Taken together, our data show a critical and nonredundant role for Th9 cells and IL-9 in host-protective type 2 immunity against parasitic worm infection. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. Epithelial cells from smokers modify dendritic cell responses in the context of influenza infection

    Science.gov (United States)

    Epidemiologic evidence suggests that cigarette smoking is a risk factor for infection with influenza, but the mechanisms underlying this susceptibility remain unknown. To ascertain if airway epithelial cells from smokers demonstrate a decreased ability to orchestrate an influenza...

  14. A Three-Dimensional Cell Culture Model To Study Enterovirus Infection of Polarized Intestinal Epithelial Cells.

    Science.gov (United States)

    Drummond, Coyne G; Nickerson, Cheryl A; Coyne, Carolyn B

    2016-01-01

    Despite serving as the primary entry portal for coxsackievirus B (CVB), little is known about CVB infection of the intestinal epithelium, owing at least in part to the lack of suitable in vivo models and the inability of cultured cells to recapitulate the complexity and structure associated with the gastrointestinal (GI) tract. Here, we report on the development of a three-dimensional (3-D) organotypic cell culture model of Caco-2 cells to model CVB infection of the gastrointestinal epithelium. We show that Caco-2 cells grown in 3-D using the rotating wall vessel (RWV) bioreactor recapitulate many of the properties of the intestinal epithelium, including the formation of well-developed tight junctions, apical-basolateral polarity, brush borders, and multicellular complexity. In addition, transcriptome analyses using transcriptome sequencing (RNA-Seq) revealed the induction of a number of genes associated with intestinal epithelial differentiation and/or intestinal processes in vivo when Caco-2 cells were cultured in 3-D. Applying this model to CVB infection, we found that although the levels of intracellular virus production were similar in two-dimensional (2-D) and 3-D Caco-2 cell cultures, the release of infectious CVB was enhanced in 3-D cultures at early stages of infection. Unlike CVB, the replication of poliovirus (PV) was significantly reduced in 3-D Caco-2 cell cultures. Collectively, our studies show that Caco-2 cells grown in 3-D using the RWV bioreactor provide a cell culture model that structurally and transcriptionally represents key aspects of cells in the human GI tract and can thus be used to expand our understanding of enterovirus-host interactions in intestinal epithelial cells. IMPORTANCE Coxsackievirus B (CVB), a member of the enterovirus family of RNA viruses, is associated with meningitis, pericarditis, diabetes, dilated cardiomyopathy, and myocarditis, among other pathologies. CVB is transmitted via the fecal-oral route and encounters the

  15. Correlation of cell surface marker expression with African swine fever virus infection.

    Science.gov (United States)

    Lithgow, Pamela; Takamatsu, Haru; Werling, Dirk; Dixon, Linda; Chapman, Dave

    2014-01-31

    The expression of surface markers on African swine fever virus (ASFV) infected cells was evaluated to assess their involvement in infection. Previous findings indicated CD163 expression was correlated with ASFV susceptibility. However, in this study the expression of porcine CD163 on cell lines did not increase the infection rate of these cells indicating other factors are likely to be important in determining susceptibility to infection. On adherent porcine bone marrow (pBM) cells the expression of CD45 was strongly correlated with infection. CD163 and CD203a expression correlated at intermediate levels with infection, indicating cells expressing these markers could become infected but were not preferentially infected by the virus. Most of the cells expressing MHCII were infected, indicating that they may be preferentially infected although expression of MHCII was not essential for infection and a large percentage of the infected cells were MHCII negative. CD16 showed a marked decrease in expression following infection and significantly lower levels of infected cells were shown to express CD16. Altogether these results suggest CD163 may be involved in ASFV infection but it may not be essential; the results also highlight the importance of other cell markers which requiring further investigation.

  16. Myeloid infection links epithelial and B cell tropisms of Murid Herpesvirus-4.

    Directory of Open Access Journals (Sweden)

    Bruno Frederico

    2012-09-01

    Full Text Available Gamma-herpesviruses persist in lymphocytes and cause disease by driving their proliferation. Lymphocyte infection is therefore a key pathogenetic event. Murid Herpesvirus-4 (MuHV-4 is a rhadinovirus that like the related Kaposi's Sarcoma-associated Herpesvirus persists in B cells in vivo yet infects them poorly in vitro. Here we used MuHV-4 to understand how virion tropism sets the path to lymphocyte colonization. Virions that were highly infectious in vivo showed a severe post-binding block to B cell infection. Host entry was accordingly an epithelial infection and B cell infection a secondary event. Macrophage infection by cell-free virions was also poor, but improved markedly when virion binding improved or when macrophages were co-cultured with infected fibroblasts. Under the same conditions B cell infection remained poor; it improved only when virions came from macrophages. This reflected better cell penetration and correlated with antigenic changes in the virion fusion complex. Macrophages were seen to contact acutely infected epithelial cells, and cre/lox-based virus tagging showed that almost all the virus recovered from lymphoid tissue had passed through lysM(+ and CD11c(+ myeloid cells. Thus MuHV-4 reached B cells in 3 distinct stages: incoming virions infected epithelial cells; infection then passed to myeloid cells; glycoprotein changes then allowed B cell infection. These data identify new complexity in rhadinovirus infection and potentially also new vulnerability to intervention.

  17. Myeloid infection links epithelial and B cell tropisms of Murid Herpesvirus-4.

    Science.gov (United States)

    Frederico, Bruno; Milho, Ricardo; May, Janet S; Gillet, Laurent; Stevenson, Philip G

    2012-09-01

    Gamma-herpesviruses persist in lymphocytes and cause disease by driving their proliferation. Lymphocyte infection is therefore a key pathogenetic event. Murid Herpesvirus-4 (MuHV-4) is a rhadinovirus that like the related Kaposi's Sarcoma-associated Herpesvirus persists in B cells in vivo yet infects them poorly in vitro. Here we used MuHV-4 to understand how virion tropism sets the path to lymphocyte colonization. Virions that were highly infectious in vivo showed a severe post-binding block to B cell infection. Host entry was accordingly an epithelial infection and B cell infection a secondary event. Macrophage infection by cell-free virions was also poor, but improved markedly when virion binding improved or when macrophages were co-cultured with infected fibroblasts. Under the same conditions B cell infection remained poor; it improved only when virions came from macrophages. This reflected better cell penetration and correlated with antigenic changes in the virion fusion complex. Macrophages were seen to contact acutely infected epithelial cells, and cre/lox-based virus tagging showed that almost all the virus recovered from lymphoid tissue had passed through lysM(+) and CD11c(+) myeloid cells. Thus MuHV-4 reached B cells in 3 distinct stages: incoming virions infected epithelial cells; infection then passed to myeloid cells; glycoprotein changes then allowed B cell infection. These data identify new complexity in rhadinovirus infection and potentially also new vulnerability to intervention.

  18. Trypanosoma cruzi: single cell live imaging inside infected tissues

    Science.gov (United States)

    Ferreira, Bianca Lima; Orikaza, Cristina Mary; Cordero, Esteban Mauricio

    2016-01-01

    Summary Although imaging the live Trypanosoma cruzi parasite is a routine technique in most laboratories, identification of the parasite in infected tissues and organs has been hindered by their intrinsic opaque nature. We describe a simple method for in vivo observation of live single‐cell Trypanosoma cruzi parasites inside mammalian host tissues. BALB/c or C57BL/6 mice infected with DsRed‐CL or GFP‐G trypomastigotes had their organs removed and sectioned with surgical blades. Ex vivo organ sections were observed under confocal microscopy. For the first time, this procedure enabled imaging of individual amastigotes, intermediate forms and motile trypomastigotes within infected tissues of mammalian hosts. PMID:26639617

  19. Targeted Cytotoxic Therapy Kills Persisting HIV Infected Cells During ART

    Science.gov (United States)

    Denton, Paul W.; Long, Julie M.; Wietgrefe, Stephen W.; Sykes, Craig; Spagnuolo, Rae Ann; Snyder, Olivia D.; Perkey, Katherine; Archin, Nancie M.; Choudhary, Shailesh K.; Yang, Kuo; Hudgens, Michael G.; Pastan, Ira; Haase, Ashley T.; Kashuba, Angela D.; Berger, Edward A.; Margolis, David M.; Garcia, J. Victor

    2014-01-01

    Antiretroviral therapy (ART) can reduce HIV levels in plasma to undetectable levels, but rather little is known about the effects of ART outside of the peripheral blood regarding persistent virus production in tissue reservoirs. Understanding the dynamics of ART-induced reductions in viral RNA (vRNA) levels throughout the body is important for the development of strategies to eradicate infectious HIV from patients. Essential to a successful eradication therapy is a component capable of killing persisting HIV infected cells during ART. Therefore, we determined the in vivo efficacy of a targeted cytotoxic therapy to kill infected cells that persist despite long-term ART. For this purpose, we first characterized the impact of ART on HIV RNA levels in multiple organs of bone marrow-liver-thymus (BLT) humanized mice and found that antiretroviral drug penetration and activity was sufficient to reduce, but not eliminate, HIV production in each tissue tested. For targeted cytotoxic killing of these persistent vRNA+ cells, we treated BLT mice undergoing ART with an HIV-specific immunotoxin. We found that compared to ART alone, this agent profoundly depleted productively infected cells systemically. These results offer proof-of-concept that targeted cytotoxic therapies can be effective components of HIV eradication strategies. PMID:24415939

  20. Targeted cytotoxic therapy kills persisting HIV infected cells during ART.

    Science.gov (United States)

    Denton, Paul W; Long, Julie M; Wietgrefe, Stephen W; Sykes, Craig; Spagnuolo, Rae Ann; Snyder, Olivia D; Perkey, Katherine; Archin, Nancie M; Choudhary, Shailesh K; Yang, Kuo; Hudgens, Michael G; Pastan, Ira; Haase, Ashley T; Kashuba, Angela D; Berger, Edward A; Margolis, David M; Garcia, J Victor

    2014-01-01

    Antiretroviral therapy (ART) can reduce HIV levels in plasma to undetectable levels, but rather little is known about the effects of ART outside of the peripheral blood regarding persistent virus production in tissue reservoirs. Understanding the dynamics of ART-induced reductions in viral RNA (vRNA) levels throughout the body is important for the development of strategies to eradicate infectious HIV from patients. Essential to a successful eradication therapy is a component capable of killing persisting HIV infected cells during ART. Therefore, we determined the in vivo efficacy of a targeted cytotoxic therapy to kill infected cells that persist despite long-term ART. For this purpose, we first characterized the impact of ART on HIV RNA levels in multiple organs of bone marrow-liver-thymus (BLT) humanized mice and found that antiretroviral drug penetration and activity was sufficient to reduce, but not eliminate, HIV production in each tissue tested. For targeted cytotoxic killing of these persistent vRNA(+) cells, we treated BLT mice undergoing ART with an HIV-specific immunotoxin. We found that compared to ART alone, this agent profoundly depleted productively infected cells systemically. These results offer proof-of-concept that targeted cytotoxic therapies can be effective components of HIV eradication strategies.

  1. Turnover rates of B cells, T cells, and NK cells in simian immunodeficiency virus-infected and uninfected rhesus macaques

    NARCIS (Netherlands)

    Boer, R.J. de; Mohri, H.; Ho, D.D.; Perelson, A.S.

    2003-01-01

    We determined average cellular turnover rates by fitting mathematical models to 5-bromo-2'-deoxyuridine measurements in SIV-infected and uninfected rhesus macaques. The daily turnover rates of CD4(+) T cells, CD4(-) T cells, CD20(+) B cells, and CD16(+) NK cells in normal uninfected rhesus macaques

  2. Effect of Human Cytomegalovirus Infection on Nerve Growth Factor Expression in Human Glioma U251 Cells

    Institute of Scientific and Technical Information of China (English)

    HAI-TAO WANG; BIN WANG; ZHI-JUN LIU; ZHI-QIANG BAI; LING LI; HAI-YAN LIU; DONG-MENG QIAN; ZHI-YONG YAN; XU-XIA SONG

    2009-01-01

    Objectives To explore the change of endogenic nerve growth factor (NGF) expression in human glioma cells infected with human cytomegalovirus (HCMV). Methods U251 cells were cultured in RPMI 1640 culture medium and infected with HCMV AD169 strain in vitro to establish a cell model of viral infection. Morphologic changes of U251 cells were observed under inverted microscope before and after infection with HCMV. Expression of NGF gene and protein of cells was detected by RT-PCR and Western blotting before and after infection with HCMV. Results The cytopathic effects of HCMV-infected cells appeared on day 5 after infection. However, differential NGF expression was evident on day 7. NGF expression was decreased significantly in U251 cells on day 7 after infection in comparison with control group (P<0.05). Conclusion HCMV can down-regulate endogenous NGF levels in human glioma cell line U251.

  3. Dendritic cells are less susceptible to human immunodeficiency virus type 2 (HIV-2) infection than to HIV-1 infection

    NARCIS (Netherlands)

    M.G. Duvall (Melody); K. Loré (Karin); H. Blaak (Hetty); D.A. Ambrozak (David); W.C. Adams (William); K. Santos (Kathlyn); C. Geldmacher (Christof); J.R. Mascola (John); A.J. McMichael (Andrew); A. Jaye (Assan); H. Whittle (Hilton); S.L. Rowland-Jones (Sarah); R.A. Koup (Richard)

    2007-01-01

    textabstractHuman immunodeficiency virus type 1 (HIV-1) infection of dendritic cells (DCs) has been documented in vivo and may be an important contributor to HIV-1 transmission and pathogenesis. HIV-1-specific CD4+T cells respond to HIV antigens presented by HIV-1-infected DCs and in this process

  4. A tubular segmented-flow bioreactor for the infection of insect cells with recombinant baculovirus

    OpenAIRE

    Hu, Yu-Chen; Wang, Ming-Ying; Bentley, William E.

    1997-01-01

    A continuous process of insect cell (S f9) growth and baculovirus infection is tested with the sequential combination of a CSTR and a tubular reactor. A tubular infection reactor enables continuous introduction of baculovirus and therefore avoids the ‘passage effect’ observed in two-stage CSTR systems. Moreover, a tubular reactor can be used to test cell infection kinetics and the subsequent metabolism of infected insect cells. Unlike batch and CSTR culture, cells in a horizontally positioned...

  5. Antigen-activated dendritic cells ameliorate influenza A infections

    Science.gov (United States)

    Boonnak, Kobporn; Vogel, Leatrice; Orandle, Marlene; Zimmerman, Daniel; Talor, Eyal; Subbarao, Kanta

    2013-01-01

    Influenza A viruses cause significant morbidity and mortality worldwide. There is a need for alternative or adjunct therapies, as resistance to currently used antiviral drugs is emerging rapidly. We tested ligand epitope antigen presentation system (LEAPS) technology as a new immune-based treatment for influenza virus infection in a mouse model. Influenza-J-LEAPS peptides were synthesized by conjugating the binding ligand derived from the β2-microglobulin chain of the human MHC class I molecule (J-LEAPS) with 15 to 30 amino acid–long peptides derived from influenza virus NP, M, or HA proteins. DCs were stimulated with influenza-J-LEAPS peptides (influenza-J-LEAPS) and injected intravenously into infected mice. Antigen-specific LEAPS-stimulated DCs were effective in reducing influenza virus replication in the lungs and enhancing survival of infected animals. Additionally, they augmented influenza-specific T cell responses in the lungs and reduced the severity of disease by limiting excessive cytokine responses, which are known to contribute to morbidity and mortality following influenza virus infection. Our data demonstrate that influenza-J-LEAPS–pulsed DCs reduce virus replication in the lungs, enhance survival, and modulate the protective immune responses that eliminate the virus while preventing excessive cytokines that could injure the host. This approach shows promise as an adjunct to antiviral treatment of influenza virus infections. PMID:23934125

  6. PD-L1 Expression on Retrovirus-Infected Cells Mediates Immune Escape from CD8+ T Cell Killing.

    Directory of Open Access Journals (Sweden)

    Ilseyar Akhmetzyanova

    2015-10-01

    Full Text Available Cytotoxic CD8+ T Lymphocytes (CTL efficiently control acute virus infections but can become exhausted when a chronic infection develops. Signaling of the inhibitory receptor PD-1 is an important mechanism for the development of virus-specific CD8+ T cell dysfunction. However, it has recently been shown that during the initial phase of infection virus-specific CD8+ T cells express high levels of PD-1, but are fully competent in producing cytokines and killing virus-infected target cells. To better understand the role of the PD-1 signaling pathway in CD8+ T cell cytotoxicity during acute viral infections we analyzed the expression of the ligand on retrovirus-infected cells targeted by CTLs. We observed increased levels of PD-L1 expression after infection of cells with the murine Friend retrovirus (FV or with HIV. In FV infected mice, virus-specific CTLs efficiently eliminated infected target cells that expressed low levels of PD-L1 or that were deficient for PD-L1 but the population of PD-L1high cells escaped elimination and formed a reservoir for chronic FV replication. Infected cells with high PD-L1 expression mediated a negative feedback on CD8+ T cells and inhibited their expansion and cytotoxic functions. These findings provide evidence for a novel immune escape mechanism during acute retroviral infection based on PD-L1 expression levels on virus infected target cells.

  7. SAMHD1 controls cell cycle status, apoptosis and HIV-1 infection in monocytic THP-1 cells

    Energy Technology Data Exchange (ETDEWEB)

    Bonifati, Serena [Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, OH (United States); Daly, Michele B. [Center for Drug Discovery, Department of Pediatrics, School of Medicine, Emory University, Atlanta, GA (United States); St Gelais, Corine; Kim, Sun Hee [Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, OH (United States); Hollenbaugh, Joseph A.; Shepard, Caitlin [Center for Drug Discovery, Department of Pediatrics, School of Medicine, Emory University, Atlanta, GA (United States); Kennedy, Edward M. [Department of Molecular Genetics and Microbiology, Duke University, Durham, NC (United States); Kim, Dong-Hyun [Department of Pharmacy, School of Pharmacy, Kyung-Hee University, Seoul (Korea, Republic of); Schinazi, Raymond F. [Center for Drug Discovery, Department of Pediatrics, School of Medicine, Emory University, Atlanta, GA (United States); Kim, Baek, E-mail: baek.kim@emory.edu [Center for Drug Discovery, Department of Pediatrics, School of Medicine, Emory University, Atlanta, GA (United States); Department of Pharmacy, School of Pharmacy, Kyung-Hee University, Seoul (Korea, Republic of); Wu, Li, E-mail: wu.840@osu.edu [Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, OH (United States)

    2016-08-15

    SAMHD1 limits HIV-1 infection in non-dividing myeloid cells by decreasing intracellular dNTP pools. HIV-1 restriction by SAMHD1 in these cells likely prevents activation of antiviral immune responses and modulates viral pathogenesis, thus highlighting a critical role of SAMHD1 in HIV-1 physiopathology. Here, we explored the function of SAMHD1 in regulating cell proliferation, cell cycle progression and apoptosis in monocytic THP-1 cells. Using the CRISPR/Cas9 technology, we generated THP-1 cells with stable SAMHD1 knockout. We found that silencing of SAMHD1 in cycling cells stimulates cell proliferation, redistributes cell cycle population in the G{sub 1}/G{sub 0} phase and reduces apoptosis. These alterations correlated with increased dNTP levels and more efficient HIV-1 infection in dividing SAMHD1 knockout cells relative to control. Our results suggest that SAMHD1, through its dNTPase activity, affects cell proliferation, cell cycle distribution and apoptosis, and emphasize a key role of SAMHD1 in the interplay between cell cycle regulation and HIV-1 infection.

  8. Infection strategies of intestinal parasite pathogens and host cell responses

    Directory of Open Access Journals (Sweden)

    Bruno Martorell Di Genova

    2016-03-01

    Full Text Available Giardia lamblia, Cryptosporidium spp. and Entamoeba histolytica are important pathogenic intestinal parasites and are amongst the leading cause worldwide of diarrheal illness in humans. Diseases caused by these organisms, Giardiasis, Cryptosporidiosis and Amoebiasis, respectively, are characterized by self-limited diarrhea but can evolve to long-term complications. The cellular and molecular mechanisms underlying the pathogenesis of diarrhea associated with these tree pathogens are being unraveled, with knowledge of both the strategies explored by the parasites to establish infection and the methods evolved by hosts to avoid it. Special attention is being given to molecules participating in parasite-host interaction and in the mechanisms implicated in the diseases pathophysiologic processes. This review focuses on cell mechanisms that are modulated during infection, including gene transcription, cytoskeleton rearrangements, signal transduction pathways and cell death.

  9. Rhizomucor and Scedosporium Infection Post Hematopoietic Stem-Cell Transplant

    Directory of Open Access Journals (Sweden)

    Dânia Sofia Marques

    2011-01-01

    Full Text Available Hematopoietic stem-cell transplant recipients are at increased risk of developing invasive fungal infections. This is a major cause of morbidity and mortality. We report a case of a 17-year-old male patient diagnosed with severe idiopathic acquired aplastic anemia who developed fungal pneumonitis due to Rhizomucor sp. and rhinoencephalitis due to Scedosporium apiospermum 6 and 8 months after undergoing allogeneic hematopoietic stem-cell transplant from an HLA-matched unrelated donor. Discussion highlights risk factors for invasive fungal infections (i.e., mucormycosis and scedosporiosis, its clinical features, and the factors that must be taken into account to successfully treat them (early diagnosis, correction of predisposing factors, aggressive surgical debridement, and antifungal and adjunctive therapies.

  10. Cytomegalovirus infection induces a stem cell phenotype in human primary glioblastoma cells

    DEFF Research Database (Denmark)

    Fornara, O; Bartek, J; Rahbar, A;

    2016-01-01

    Glioblastoma (GBM) is associated with poor prognosis despite aggressive surgical resection, chemotherapy, and radiation therapy. Unfortunately, this standard therapy does not target glioma cancer stem cells (GCSCs), a subpopulation of GBM cells that can give rise to recurrent tumors. GBMs express......-expression of these two proteins predicted poor patient survival. Infection of GBM cells with HCMV led to upregulation of CD133 and other GSCS markers (Notch1, Sox2, Oct4, Nestin). HCMV infection also promoted the growth of GBM cells as neurospheres, a behavior typically displayed by GCSCs, and this phenotype...... was prevented by either chemical inhibition of the Notch1 pathway or by treatment with the anti-viral drug ganciclovir. GBM cells that maintained expression of HCMV-IE failed to differentiate into neuronal or astrocytic phenotypes. Our findings imply that HCMV infection induces phenotypic plasticity of GBM...

  11. Infection of brain-derived cells with the human immunodeficiency virus.

    Science.gov (United States)

    Chiodi, F; Fuerstenberg, S; Gidlund, M; Asjö, B; Fenyö, E M

    1987-01-01

    A malignant glioma cell line was infected with the human T-lymphotropic virus type IIIB isolate of the human immunodeficiency virus. Infection appeared to be latent rather than productive. Through contact with monocytic or lymphoid cells, the virus present in the glioma cells could be transmitted and gave rise to a fully productive infection. Images PMID:3644020

  12. Divergent Kinetics of Proliferating T Cell Subsets in Simian Immunodeficiency Virus (SIV) Infection: SIV Eliminates the “First Responder” CD4+ T Cells in Primary Infection

    OpenAIRE

    Wang, Xiaolei; Xu, Huanbin; Pahar, Bapi; Lackner, Andrew A.; Veazey, Ronald S.

    2013-01-01

    Although increased lymphocyte turnover in chronic human immunodeficiency virus and simian immunodeficiency virus (SIV) infection has been reported in blood, there is little information on cell turnover in tissues, particularly in primary SIV infection. Here we examined the levels of proliferating T cell subsets in mucosal and peripheral lymphoid tissues of adult macaques throughout SIV infection. To specifically label cells in S-phase division, all animals were inoculated with bromodeoxyuridi...

  13. Quantitative phosphoproteomic analysis of prion-infected neuronal cells

    Directory of Open Access Journals (Sweden)

    Löwer Johannes

    2010-09-01

    Full Text Available Abstract Prion diseases or transmissible spongiform encephalopathies (TSEs are fatal diseases associated with the conversion of the cellular prion protein (PrPC to the abnormal prion protein (PrPSc. Since the molecular mechanisms in pathogenesis are widely unclear, we analyzed the global phospho-proteome and detected a differential pattern of tyrosine- and threonine phosphorylated proteins in PrPSc-replicating and pentosan polysulfate (PPS-rescued N2a cells in two-dimensional gel electrophoresis. To quantify phosphorylated proteins, we performed a SILAC (stable isotope labeling by amino acids in cell culture analysis and identified 105 proteins, which showed a regulated phosphorylation upon PrPSc infection. Among those proteins, we validated the dephosphorylation of stathmin and Cdc2 and the induced phosphorylation of cofilin in PrPSc-infected N2a cells in Western blot analyses. Our analysis showed for the first time a differentially regulated phospho-proteome in PrPSc infection, which could contribute to the establishment of novel protein markers and to the development of novel therapeutic intervention strategies in targeting prion-associated disease.

  14. Cytoadherence of the malaria-infected erythrocyte membrane to C32 melanoma cells after merozoites are released from parasitized infected cells.

    Science.gov (United States)

    Winograd, E; Robles, W M; Caldas, M L; Cortes, G T

    2001-04-01

    Infections with the human malaria parasite Plasmodium falciparum are characterized by cytoadherence of infected erythrocytes to the venular endothelium of several organs. Video microscopy studies have shown that at the end of the asexual life of P. falciparum, the residual body containing haemozoin is released to the extracellular environment along with merozoites, leaving behind an infected erythrocyte "ghost". It is possible that these infected erythrocyte "ghosts" could remain sequestered within the blood vessels of patients infected with P. falciparum even after merozoites have been released from infected erythrocytes. In this study an in vitro cytoadherence assay was developed to show that infected erythrocyte "ghosts" can interact with C32 melanoma cells. Adherent infected erythrocyte "ghosts" contain some of the subcellular compartments of the malaria-infected red blood cell such as the tubo-vesicular membrane network and remnants of the parasitophorous vacuolar membrane, but lack haemozoin.

  15. Immunoavtoradiographic demonstration of virus antigens in infected cells

    Energy Technology Data Exchange (ETDEWEB)

    Tarasishin, L.A.; Zhovnovataya, V.L.

    1986-02-01

    This paper describes a simple method of determining virus antigens, which consists essentially of the demonstration of immune complexes, formed by treatment of acetone-fixed infected cells with specific immune serum, by means of labeled protein A of S. aureus. Transplantable human HeLa cells, type 1 human adenovirus (AD 1), normal rabbit serum, and specific immune sera, obtained by immunization of rabbits with purified Ad 1 or with hexone Ad 1, and a commerical preparation of protein A of S. aureus, labeled with I 125 by the chloramine method, were used.

  16. Infection of a human respiratory epithelial cell line with rhinovirus. Induction of cytokine release and modulation of susceptibility to infection by cytokine exposure.

    OpenAIRE

    Subauste, M C; Jacoby, D B; Richards, S M; Proud, D

    1995-01-01

    Rhinovirus infections cause over one third of all colds and are a contributing factor to exacerbations of asthma. To gain insights into the early biochemical events that occur in infected epithelial cells, we develop, for the first time, a model in which a pure respiratory epithelial cell population can be routinely infected by rhinovirus. Viral infection was confirmed by demonstrating that viral titers of supernatants and lysates from infected cell increased with time and by PCR. Infection b...

  17. Altered T cell costimulation during chronic hepatitis B infection.

    Science.gov (United States)

    Barboza, Luisa; Salmen, Siham; Peterson, Darrell L; Montes, Henry; Colmenares, Melisa; Hernández, Manuel; Berrueta-Carrillo, Leidith E; Berrueta, Lisbeth

    2009-01-01

    T-cell response to hepatitis B virus (HBV) is vigorous, polyclonal and multi-specific in patients with acute hepatitis who ultimately clear the virus, whereas it is narrow and inefficient in patients with chronic disease, where inappropriate early activation events could account for viral persistence. We investigated the induction of activation receptors and cytokine production in response to HBcAg and crosslinking of CD28 molecules, in CD4+ cells from a group of chronically infected patients (CIP) and naturally immune subjects (NIS). We demonstrated that CD4+ cells from CIP did not increase levels of CD40L and CD69 following stimulation with HBcAg alone or associated to CD28 crosslinking, in contrast to subjects that resolved the infection (p<0.01). Furthermore, CD4+ cells from CIP produced elevated levels of IL-10 in response to HBcAg. These results suggest that a predominant inhibitory environment may be responsible for altered T cell costimulation, representing a pathogenic mechanism for viral persistence.

  18. Preferential infection and depletion of Mycobacterium tuberculosis-specific CD4 T cells after HIV-1 infection.

    Science.gov (United States)

    Geldmacher, Christof; Ngwenyama, Njabulo; Schuetz, Alexandra; Petrovas, Constantinos; Reither, Klaus; Heeregrave, Edwin J; Casazza, Joseph P; Ambrozak, David R; Louder, Mark; Ampofo, William; Pollakis, Georgios; Hill, Brenna; Sanga, Erica; Saathoff, Elmar; Maboko, Leonard; Roederer, Mario; Paxton, William A; Hoelscher, Michael; Koup, Richard A

    2010-12-20

    HIV-1 infection results in the progressive loss of CD4 T cells. In this study, we address how different pathogen-specific CD4 T cells are affected by HIV infection and the cellular parameters involved. We found striking differences in the depletion rates between CD4 T cells to two common opportunistic pathogens, cytomegalovirus (CMV) and Mycobacterium tuberculosis (MTB). CMV-specific CD4 T cells persisted after HIV infection, whereas MTB-specific CD4 T cells were depleted rapidly. CMV-specific CD4 T cells expressed a mature phenotype and produced very little IL-2, but large amounts of MIP-1β. In contrast, MTB-specific CD4 T cells were less mature, and most produced IL-2 but not MIP-1β. Staphylococcal enterotoxin B-stimulated IL-2-producing cells were more susceptible to HIV infection in vitro than MIP-1β-producing cells. Moreover, IL-2 production was associated with expression of CD25, and neutralization of IL-2 completely abrogated productive HIV infection in vitro. HIV DNA was found to be most abundant in IL-2-producing cells, and least abundant in MIP-1β-producing MTB-specific CD4 T cells from HIV-infected subjects with active tuberculosis. These data support the hypothesis that differences in function affect the susceptibility of pathogen-specific CD4 T cells to HIV infection and depletion in vivo, providing a potential mechanism to explain the rapid loss of MTB-specific CD4 T cells after HIV infection.

  19. Directly infected resting CD4+T cells can produce HIV Gag without spreading infection in a model of HIV latency.

    Directory of Open Access Journals (Sweden)

    Matthew J Pace

    Full Text Available Despite the effectiveness of highly active antiretroviral therapy (HAART in treating individuals infected with HIV, HAART is not a cure. A latent reservoir, composed mainly of resting CD4+T cells, drives viral rebound once therapy is stopped. Understanding the formation and maintenance of latently infected cells could provide clues to eradicating this reservoir. However, there have been discrepancies regarding the susceptibility of resting cells to HIV infection in vitro and in vivo. As we have previously shown that resting CD4+T cells are susceptible to HIV integration, we asked whether these cells were capable of producing viral proteins and if so, why resting cells were incapable of supporting productive infection. To answer this question, we spinoculated resting CD4+T cells with or without prior stimulation, and measured integration, transcription, and translation of viral proteins. We found that resting cells were capable of producing HIV Gag without supporting spreading infection. This block corresponded with low HIV envelope levels both at the level of protein and RNA and was not an artifact of spinoculation. The defect was reversed upon stimulation with IL-7 or CD3/28 beads. Thus, a population of latent cells can produce viral proteins without resulting in spreading infection. These results have implications for therapies targeting the latent reservoir and suggest that some latent cells could be cleared by a robust immune response.

  20. BACTERIAL INFECTIONS IN HEMATOPOIETIC STEM CELL TRANSPLANT RECIPIENTS

    Directory of Open Access Journals (Sweden)

    Elisa Balletto

    2015-07-01

    Full Text Available Bacterial infections are major complications after Hematopoietic Stem Cell Transplant (HSCT. They consist mainly of bloodstream infections (BSI, followed by pneumonia and gastrointestinal infections, including typhlitis and Clostridium difficile infection. Microbiological data come mostly from BSI. Coagulase negative staphylococci and Enterobacteriaceae are the most frequent pathogens causing approximately 25% of BSI each, followed by enterococci, P. aeruginosa and viridans streptococci. Bacterial pneumonia is frequent after HSCT, and Gram-negatives are predominant. Clostridium difficile infection affects approximately 15% of HSCT recipients, being more frequent in case of allogeneic than autologous HSCT. The epidemiology and the prevalence of resistant strains vary significantly between transplant centres. In some regions, multi-drug resistant Gram-negative rods are increasingly frequent. In others, vancomycin-resistant enterococci are predominant. In the era of an increasing resistance to antibiotics, the efficacy of fluoroquinolone prophylaxis and standard treatment of febrile neutropenia have been questioned. Therefore, thorough evaluation of local epidemiology is mandatory in order to decide the need for prophylaxis and the choice of the best regimen for empirical treatment of febrile neutropenia. For the latter, individualised approach has been proposed, consisting of either escalation or de-escalation strategy. De-escalation strategy is recommended is resistant bacteria should be covered upfront, mainly in patients with severe clinical presentation and previous infection or colonisation with a resistant pathogens. Non-pharmacological interventions, such as screening for resistant bacteria, applying isolation and contact precautions should be put in place in order to limit the spread of MDR bacteria. Antimicrobial stewardship program should be implemented in transplant centres.

  1. Demonstration of different modes of cell death upon herpes simplex virus 1 infection in different types of oral cells.

    Science.gov (United States)

    Huang, C R; Lin, S S; Chou, M Y; Ho, C C; Wang, L; Lee, Y L; Chen, C S; Yang, C C

    2005-01-01

    The effects of Herpes simplex virus 1 (HSV-1) infection on five different types of oral cancerous cells (neck metastasis of gingival carcinoma (GNM) cells and tongue squamous cells of carcinoma (TSCCa) and non-cancerous cells (buccal mucosal fibroblasts (BF), gingival fibroblasts (GF), oral submucosal fibrosis cells (OSF)) and one type of non-oral cancerous cells (KB cells) were investigated. In HSV-1-infected cells the cell viability, CPE, viral antigens accumulation, caspase-3 activity, annexin V binding and DNA fragmentation were estimated. Three different forms or pathways of cell death were considered: apoptosis (the presence or rise of caspase-3 activity, DNA fragmentation and annexin V binding), slow cell death (the presence or rise of DNA fragmentation, the absence or decline of caspase-3 activity and annexin V binding), and necrosis (the absence of decline of caspase-3 activity, DNA fragmentation and annexin V binding). The viability of all cell types, except for KB cells, was reduced by the infection. CPE and viral antigens data demonstrated that all six types of cells could be infected with HSV-1. Upon HSV-1 infection there occurred (i) a classical apoptosis in GF cells, (ii) apoptosis in the early phase of infection and necrosis in the late phase of infection in GNM and TSCCa cells, (iii) slow cell death followed by necrosis in BF and OSF cells (however, these cells showed a different type of CPE), (iv) a classical slow cell death in KB cells. It is hypothesized that HSV-1 infection has a potential to induce several distinct pathways leading to cell death or several forms of cell death. Moreover, more than one pathway may be involved in the death of particular cell type. As HSV-1 was demonstrated to infect different oral and non-oral cells and cause different pathways or forms of cell death, the safety of using HSV-1 as a vector for gene therapy should be re-considered.

  2. Microsporidia infection impacts the host cell's cycle and reduces host cell apoptosis

    Science.gov (United States)

    Higes, Mariano; Sagastume, Soledad; Juarranz, Ángeles; Dias-Almeida, Joyce; Budge, Giles E.; Meana, Aránzazu; Boonham, Neil

    2017-01-01

    Intracellular parasites can alter the cellular machinery of host cells to create a safe haven for their survival. In this regard, microsporidia are obligate intracellular fungal parasites with extremely reduced genomes and hence, they are strongly dependent on their host for energy and resources. To date, there are few studies into host cell manipulation by microsporidia, most of which have focused on morphological aspects. The microsporidia Nosema apis and Nosema ceranae are worldwide parasites of honey bees, infecting their ventricular epithelial cells. In this work, quantitative gene expression and histology were studied to investigate how these two parasites manipulate their host’s cells at the molecular level. Both these microsporidia provoke infection-induced regulation of genes involved in apoptosis and the cell cycle. The up-regulation of buffy (which encodes a pro-survival protein) and BIRC5 (belonging to the Inhibitor Apoptosis protein family) was observed after infection, shedding light on the pathways that these pathogens use to inhibit host cell apoptosis. Curiously, different routes related to cell cycle were modified after infection by each microsporidia. In the case of N. apis, cyclin B1, dacapo and E2F2 were up-regulated, whereas only cyclin E was up-regulated by N. ceranae, in both cases promoting the G1/S phase transition. This is the first report describing molecular pathways related to parasite-host interactions that are probably intended to ensure the parasite’s survival within the cell. PMID:28152065

  3. Memory CD8+ T cell differentiation in viral infection: A cell for all seasons

    Institute of Scientific and Technical Information of China (English)

    Henry Radziewicz; Luke Uebelhoer; Bertram Bengsch; Arash Grakoui

    2007-01-01

    Chronic viral infections such as hepatitis B virus (HBV),hepatitis C virus (HCV) and human immunodeficiency virus (HIV) are major global health problems affecting more than 500 million people worldwide. Virus-specific CD8+ T cells play an important role in the course and outcome of these viral infections and it is hypothesized that altered or impaired differentiation of virusspecific CD8+ T cells contributes to the development of persistence and/or disease progression. A deeper understanding of the mechanisms responsible for functional differentiation of CD8+ T cells is essential for the generation of successful therapies aiming to strengthen the adaptive component of the immune system.

  4. Epstein-Barr virus infection and persistence in nasopharyngeal epithelial cells

    Institute of Scientific and Technical Information of China (English)

    Chi Man Tsang; Wen Deng; Yim Ling Yip; Mu-Sheng Zeng; Kwok Wai Lo; Sai Wah Tsao

    2014-01-01

    Epstein-Barr virus (EBV) infection is closely associated with undifferentiated nasopharyngeal carcinoma (NPC), strongly implicating a role for EBV in NPC pathogenesis; conversely, EBV infection is rarely detected in normal nasopharyngeal epithelial tissues. In general, EBV does not show a strong tropism for infecting human epithelial cels, and EBV infection in oropharyngeal epithelial cels is believed to be lytic in nature. To establish life-long infection in humans, EBV has evolved efficient strategies to infect B cels and hijack their celular machinery for latent infection. Lytic EBV infection in oropharyngeal epithelial cels, though an infrequent event, is believed to be a major source of infectious EBV particles for salivary transmission. The biological events associated with nasopharyngeal epithelial cells are only beginning to be understood with the advancement of EBV infection methods and the availability of nasopharyngeal epithelial cel models for EBV infection studies. EBV infection in human epithelial cels is a highly inefficient process compared to that in B cels, which express the complement receptor type 2 (CR2) to mediate EBV infection. Although receptor(s) on the epithelial cell surface for EBV infection remain(s) to be identified, EBV infection in epithelial cels could be achieved via the interaction of glycoproteins on the viral envelope with surface integrins on epithelial cels, which might trigger membrane fusion to internalize EBV in cels. Normal nasopharyngeal epithelial cells are not permissive for latent EBV infection, and EBV infection in normal nasopharyngeal epithelial cells usually results in growth arrest. However, genetic alterations in premalignant nasopharyngeal epithelial cells, including p16 deletion and cyclin D1 overexpression, could override the growth inhibitory effect of EBV infection to support stable and latent EBV infection in nasopharyngeal epithelial cells. The EBV episome in NPC is clonal in nature, suggesting that NPC

  5. Divergent kinetics of proliferating T cell subsets in simian immunodeficiency virus (SIV) infection: SIV eliminates the "first responder" CD4+ T cells in primary infection.

    Science.gov (United States)

    Wang, Xiaolei; Xu, Huanbin; Pahar, Bapi; Lackner, Andrew A; Veazey, Ronald S

    2013-06-01

    Although increased lymphocyte turnover in chronic human immunodeficiency virus and simian immunodeficiency virus (SIV) infection has been reported in blood, there is little information on cell turnover in tissues, particularly in primary SIV infection. Here we examined the levels of proliferating T cell subsets in mucosal and peripheral lymphoid tissues of adult macaques throughout SIV infection. To specifically label cells in S-phase division, all animals were inoculated with bromodeoxyuridine 24 h prior to sampling. In healthy macaques, the highest levels of proliferating CD4(+) and CD8(+) T cells were in blood and, to a lesser extent, in spleen. Substantial percentages of proliferating cells were also found in intestinal tissues, including the jejunum, ileum, and colon, but very few proliferating cells were detected in lymph nodes (axillary and mesenteric). Moreover, essentially all proliferating T cells in uninfected animals coexpressed CD95 and many coexpressed CCR5 in the tissues examined. Confocal microscopy also demonstrated that proliferating cells were substantial viral target cells for SIV infection and viral replication. After acute SIV infection, percentages of proliferating CD4(+) and CD8(+) T cells were significantly higher in tissues of chronically infected macaques and macaques with AIDS than in those of the controls. Surprisingly, however, we found that proliferating CD4(+) T cells were selectively decreased in very early infection (8 to 10 days postinoculation [dpi]). In contrast, levels of proliferating CD8(+) T cells rapidly increased after SIV infection, peaked by 13 to 21 dpi, and thereafter remained significantly higher than those in the controls. Taken together, these findings suggest that SIV selectively infects and destroys dividing, nonspecific CD4(+) T cells in acute infection, resulting in homeostatic changes and perhaps continuing loss of replication capacity to respond to nonspecific and, later, SIV-specific antigens.

  6. Cooperation of B cells and T cells is required for survival of mice infected with vesicular stomatitis virus

    DEFF Research Database (Denmark)

    Thomsen, Allan Randrup; Nansen, A; Andersen, C

    1997-01-01

    To define the role of T cells and B cells in resistance to vesicular stomatitis virus (VSV) infection, knockout mice with different specific immune defects on an identical background were infected i.v. and the outcome of infection was compared; in this way a more complete picture of the relative...

  7. Type I Interferons and NK Cells Restrict Gammaherpesvirus Lymph Node Infection.

    Science.gov (United States)

    Lawler, Clara; Tan, Cindy S E; Simas, J Pedro; Stevenson, Philip G

    2016-10-15

    Gammaherpesviruses establish persistent, systemic infections and cause cancers. Murid herpesvirus 4 (MuHV-4) provides a unique window into the early events of host colonization. It spreads via lymph nodes. While dendritic cells (DC) pass MuHV-4 to lymph node B cells, subcapsular sinus macrophages (SSM), which capture virions from the afferent lymph, restrict its spread. Understanding how this restriction works offers potential clues to a more comprehensive defense. Type I interferon (IFN-I) blocked SSM lytic infection and reduced lytic cycle-independent viral reporter gene expression. Plasmacytoid DC were not required, but neither were SSM the only source of IFN-I, as IFN-I blockade increased infection in both intact and SSM-depleted mice. NK cells restricted lytic SSM infection independently of IFN-I, and SSM-derived virions spread to the spleen only when both IFN-I responses and NK cells were lacking. Thus, multiple innate defenses allowed SSM to adsorb virions from the afferent lymph with relative impunity. Enhancing IFN-I and NK cell recruitment could potentially also restrict DC infection and thus improve infection control. Human gammaherpesviruses cause cancers by infecting B cells. However, vaccines designed to block virus binding to B cells have not stopped infection. Using a related gammaherpesvirus of mice, we have shown that B cells are infected not via cell-free virus but via infected myeloid cells. This suggests a different strategy to stop B cell infection: stop virus production by myeloid cells. Not all myeloid infection is productive. We show that subcapsular sinus macrophages, which do not pass infection to B cells, restrict gammaherpesvirus production by recruiting type I interferons and natural killer cells. Therefore, a vaccine that speeds the recruitment of these defenses might stop B cell infection. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  8. Dynamics of Salmonella infection of macrophages at the single cell level.

    Science.gov (United States)

    Gog, Julia R; Murcia, Alicia; Osterman, Natan; Restif, Olivier; McKinley, Trevelyan J; Sheppard, Mark; Achouri, Sarra; Wei, Bin; Mastroeni, Pietro; Wood, James L N; Maskell, Duncan J; Cicuta, Pietro; Bryant, Clare E

    2012-10-07

    Salmonella enterica causes a range of diseases. Salmonellae are intracellular parasites of macrophages, and the control of bacteria within these cells is critical to surviving an infection. The dynamics of the bacteria invading, surviving, proliferating in and killing macrophages are central to disease pathogenesis. Fundamentally important parameters, however, such as the cellular infection rate, have not previously been calculated. We used two independent approaches to calculate the macrophage infection rate: mathematical modelling of Salmonella infection experiments, and analysis of real-time video microscopy of infection events. Cells repeatedly encounter salmonellae, with the bacteria often remain associated with the macrophage for more than ten seconds. Once Salmonella encounters a macrophage, the probability of that bacterium infecting the cell is remarkably low: less than 5%. The macrophage population is heterogeneous in terms of its susceptibility to the first infection event. Once infected, a macrophage can undergo further infection events, but these reinfection events occur at a lower rate than that of the primary infection.

  9. Sickle Cell Trait Protects Against Plasmodium falciparum Infection

    Science.gov (United States)

    Billo, Mounkaila A.; Johnson, Eric S.; Doumbia, Seydou O.; Poudiougou, Belco; Sagara, Issaka; Diawara, Sory I.; Diakité, Mahamadou; Diallo, Mouctar; Doumbo, Ogobara K.; Tounkara, Anatole; Rice, Janet; James, Mark A.; Krogstad, Donald J.

    2012-01-01

    Although sickle cell trait protects against severe disease due to Plasmodium falciparum, it has not been clear whether sickle trait also protects against asymptomatic infection (parasitemia). To address this question, the authors identified 171 persistently smear-negative children and 450 asymptomatic persistently smear-positive children in Bancoumana, Mali (June 1996 to June 1998). They then followed both groups for 2 years using a cohort-based strategy. Among the 171 children with persistently negative smears, the median time for conversion to smear-positive was longer for children with sickle trait than for children without (274 vs. 108 days, P sickle trait than for children without (190 vs. 365 days; P = 0.02). These protective effects of sickle trait against asymptomatic P. falciparum infection under conditions of natural transmission were demonstrable using a cohort-based approach but not when the same data were examined using a cross-sectional approach. PMID:23035141

  10. Gene expression in epithelial cells in response to pneumovirus infection

    Directory of Open Access Journals (Sweden)

    Rosenberg Helene F

    2001-05-01

    Full Text Available Abstract Respiratory syncytial virus (RSV and pneumonia virus of mice (PVM are viruses of the family Paramyxoviridae, subfamily pneumovirus, which cause clinically important respiratory infections in humans and rodents, respectively. The respiratory epithelial target cells respond to viral infection with specific alterations in gene expression, including production of chemoattractant cytokines, adhesion molecules, elements that are related to the apoptosis response, and others that remain incompletely understood. Here we review our current understanding of these mucosal responses and discuss several genomic approaches, including differential display reverse transcription-polymerase chain reaction (PCR and gene array strategies, that will permit us to unravel the nature of these responses in a more complete and systematic manner.

  11. Perfluorocarbon emulsion therapy attenuates pneumococcal infection in sickle cell mice.

    Science.gov (United States)

    Helmi, Nawal; Andrew, Peter W; Pandya, Hitesh C

    2015-05-15

    Impaired immunity and tissue hypoxia-ischemia are strongly linked with Streptococcus pneumoniae pathogenesis in patients with sickle cell anemia. Perfluorocarbon emulsions (PFCEs) have high O2-dissolving capacity and can alleviate tissue hypoxia. Here, we evaluate the effects of intravenous PFCE therapy in transgenic sickle cell (HbSS) mice infected with S. pneumoniae. HbSS and C57BL/6 (control) mice intravenously infected with S. pneumoniae were treated intravenously with PFCE or phosphate-buffered saline (PBS) and then managed in either air/O2 (FiO2 proportion, 50%; hereafter referred to as the PFCE-O2 and PBS-O2 groups) or air only (hereafter, the PFCE-air and PBS-air groups) gas mixtures. Lungs were processed for leukocyte and bacterial counts and cytokine measurements. HbSS mice developed severe pneumococcal infection significantly faster than C57BL/6 mice (Kaplan-Maier analysis, P < .05). PFCE-O2-treated HbSS mice had significantly better survival at 72 hours than HBSS mice treated with PFCE-air, PBS-O2, or PBS-air (P < .05). PFCE-O2-treated HbSS mice also had significantly lower pulmonary leukocyte counts, lower interleukin 1β and interferon γ levels, and higher interleukin 10 levels than PFCE-air-treated HbSS mice. Clearance of S. pneumoniae from lungs of HbSS mice or C57BL/6 mice was not altered by PFCE treatment. Improved survival of PFCE-O₂-treated HbSS mice infected with S. pneumoniae is associated with altered pulmonary inflammation but not enhanced bacterial clearance.

  12. Pseudomonas aeruginosa forms Biofilms in Acute InfectionIndependent of Cell-to-Cell Signaling

    Energy Technology Data Exchange (ETDEWEB)

    Schaber, J. Andy; Triffo, W.J.; Suh, Sang J.; Oliver, Jeffrey W.; Hastert, Mary C.; Griswold, John A.; Auer, Manfred; Hamood, Abdul N.; Rumbaugh, Kendra P.

    2006-09-20

    Biofilms are bacterial communities residing within a polysaccharide matrix that are associated with persistence and antibiotic resistance in chronic infections. We show that the opportunistic pathogen Pseudomonas aeruginosa forms biofilms within 8 hours of infection in thermally-injured mice, demonstrating that biofilms contribute to bacterial colonization in acute infections. P. aeruginosa biofilms were visualized within burned tissue surrounding blood vessels and adipose cells. Although quorum sensing (QS), a bacterial signaling mechanism, coordinates differentiation of biofilms in vitro, wild type and QS-deficient P. aeruginosa formed similar biofilms in vivo. Our findings demonstrate that P. aeruginosa forms biofilms on specific host tissues independent of QS.

  13. Kinetics of liver macrophages (Kupffer cells) in SIV-infected macaques

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    Ahsan, Muhammad H.; Gill, Amy F.; Alvarez, Xavier; Lackner, Andrew A.; Veazey, Ronald S., E-mail: rveazey@tulane.edu

    2013-11-15

    Since the liver drains antigens from the intestinal tract, and since the intestinal tract is a major site of viral replication, we examined the dynamics of liver macrophages (Kupffer cells) throughout SIV infection. Absolute numbers of Kupffer cells increased in the livers in acute infection, and in animals with AIDS. Significantly higher percentages of proliferating (BrdU+) Kupffer cells were detected in acute infection and in AIDS with similar trends in blood monocytes. Significantly higher percentages of apoptotic (AC3+) Kupffer cells were also found in acute and AIDS stages. However, productively infected cells were not detected in liver of 41/42 animals examined, despite abundant infected cells in gut and lymph nodes of all animals. Increased rates of Kupffer cell proliferation resulting in an increase in Kupffer cells without productive infection indicate SIV infection affects Kupffer cells, but the liver does not appear to be a major site of productive viral replication. - Highlights: • Kupffer cells increase in the liver of SIV-infected macaques. • Increased proliferation and apoptosis of Kupffer cells occurs in SIV infection. • Productively infected cells are rarely detected in the liver. • The liver is not a major site for SIV replication.

  14. A novel single virus infection system reveals that influenza virus preferentially infects cells in g1 phase.

    Directory of Open Access Journals (Sweden)

    Ryuta Ueda

    Full Text Available BACKGROUND: Influenza virus attaches to sialic acid residues on the surface of host cells via the hemagglutinin (HA, a glycoprotein expressed on the viral envelope, and enters into the cytoplasm by receptor-mediated endocytosis. The viral genome is released and transported in to the nucleus, where transcription and replication take place. However, cellular factors affecting the influenza virus infection such as the cell cycle remain uncharacterized. METHODS/RESULTS: To resolve the influence of cell cycle on influenza virus infection, we performed a single-virus infection analysis using optical tweezers. Using this newly developed single-virus infection system, the fluorescence-labeled influenza virus was trapped on a microchip using a laser (1064 nm at 0.6 W, transported, and released onto individual H292 human lung epithelial cells. Interestingly, the influenza virus attached selectively to cells in the G1-phase. To clarify the molecular differences between cells in G1- and S/G2/M-phase, we performed several physical and chemical assays. Results indicated that: 1 the membranes of cells in G1-phase contained greater amounts of sialic acids (glycoproteins than the membranes of cells in S/G2/M-phase; 2 the membrane stiffness of cells in S/G2/M-phase is more rigid than those in G1-phase by measurement using optical tweezers; and 3 S/G2/M-phase cells contained higher content of Gb3, Gb4 and GlcCer than G1-phase cells by an assay for lipid composition. CONCLUSIONS: A novel single-virus infection system was developed to characterize the difference in influenza virus susceptibility between G1- and S/G2/M-phase cells. Differences in virus binding specificity were associated with alterations in the lipid composition, sialic acid content, and membrane stiffness. This single-virus infection system will be useful for studying the infection mechanisms of other viruses.

  15. Changes in cell adhesion molecule expression on T cells associated with systemic virus infection

    DEFF Research Database (Denmark)

    Andersson, E C; Christensen, Jan Pravsgaard; Marker, O

    1994-01-01

    Virus-induced changes in adhesion molecule expression on T cells were investigated to understand how antiviral effector cells migrate into infectious foci. FACS analysis revealed that after systemic infection with lymphocytic choriomeningitis virus a number of cell adhesion molecules, including VLA...... analyses showed that T cells with a changed adhesion molecule profile tended to present other cell surface markers indicating a state of cellular activation, e.g., IL-2R, and included all virus-specific CTL effectors. Regarding the physiologic significance of these changes in adhesion molecule expression...

  16. Infected peripheral blood mononuclear cells transmit latent varicella zoster virus infection to the guinea pig enteric nervous system.

    Science.gov (United States)

    Gan, Lin; Wang, Mingli; Chen, Jason J; Gershon, Michael D; Gershon, Anne A

    2014-10-01

    Latent wild-type (WT) and vaccine (vOka) varicella zoster virus (VZV) are found in the human enteric nervous system (ENS). VZV also infects guinea pig enteric neurons in vitro, establishes latency and can be reactivated. We therefore determined whether lymphocytes infected in vitro with VZV secrete infectious virions and can transfer infection in vivo to the ENS of recipient guinea pigs. T lymphocytes (CD3-immunoreactive) were preferentially infected following co-culture of guinea pig or human peripheral blood mononuclear cells with VZV-infected HELF. VZV proliferated in the infected T cells and expressed immediate early and late VZV genes. Electron microscopy confirmed that VZV-infected T cells produced encapsulated virions. Extracellular virus, however, was pleomorphic, suggesting degradation occurred prior to release, which was confirmed by the failure of VZV-infected T cells to secrete infectious virions. Intravenous injection of WT- or vOka-infected PBMCs, nevertheless, transmitted VZV to recipient animals (guinea pig > human lymphocytes). Two days post-inoculation, lung and liver, but not gut, contained DNA and transcripts encoding ORFs 4, 40, 66 and 67. Twenty-eight days after infection, gut contained DNA and transcripts encoding ORFs 4 and 66 but neither DNA nor transcripts could any longer be found in lung or liver. In situ hybridization revealed VZV DNA in enteric neurons, which also expressed ORF63p (but not ORF68p) immunoreactivity. Observations suggest that VZV infects T cells, which can transfer VZV to and establish latency in enteric neurons in vivo. Guinea pigs may be useful for studies of VZV pathogenesis in the ENS.

  17. In Vitro Cell Culture Infectivity Assay for Human Noroviruses

    Energy Technology Data Exchange (ETDEWEB)

    Straub, Tim M.; Honer Zu Bentrup, Kerstin A.; Orosz Coghlan, Patricia A.; Dohnalkova, Alice; Mayer, Brooke K.; Bartholomew, Rachel A.; Valdez, Catherine O.; Bruckner-Lea, Cindy J.; Gerba, Charles P.; Abbaszadegan, Morteza; Nickerson, Cheryl A.

    2007-01-30

    Human noroviruses (NoV) cause severe, self-limiting gastroenteritis that typically lasts 24 - 48 hours. The true nature of NoV pathogenesis remains unknown due to the lack of suitable tissue culture or animal models. Here we show, for the first time, that NoV can infect and replicate in an organoid, three-dimensional (3-D) model of human small intestinal epithelium (INT-407). Cellular differentiation for this model was achieved by growing the cells in 3-D on porous collagen I-coated microcarrier beads under conditions of physiological fluid shear in rotating wall vessel bioreactors. Microscopy, PCR, and fluorescent in-situ hybridization were employed to provide evidence of NoV infection. CPE and norovirus RNA was detected at each of the five cell passages for both genogroup I and II viruses. Our results demonstrate that the highly differentiated 3-D cell culture model can support the natural growth of human noroviruses, whereas previous attempts using differentiated monolayer cultures failed.

  18. Characterization of Dendritic Cell and Regulatory T Cell Functions against Mycobacterium tuberculosis Infection

    Directory of Open Access Journals (Sweden)

    Devin Morris

    2013-01-01

    Full Text Available Glutathione (GSH is a tripeptide that regulates intracellular redox and other vital aspects of cellular functions. GSH plays a major role in enhancing the immune system. Dendritic cells (DCs are potent antigen presenting cells that participate in both innate and acquired immune responses against microbial infections. Regulatory T cells (Tregs play a significant role in immune homeostasis. In this study, we investigated the effects of GSH in enhancing the innate and adaptive immune functions of DCs against Mycobacterium tuberculosis (M. tb infection. We also characterized the functions of the sub-populations of CD4+T cells such as Tregs and non-Tregs in modulating the ability of monocytes to control the intracellular M. tb infection. Our results indicate that GSH by its direct antimycobacterial activity inhibits the growth of intracellular M. tb inside DCs. GSH also increases the expressions of costimulatory molecules such as HLA-DR, CD80 and CD86 on the cell surface of DCs. Furthermore, GSH-enhanced DCs induced a higher level of T-cell proliferation. We also observed that enhancing the levels of GSH in Tregs resulted in downregulation in the levels of IL-10 and TGF-β and reduction in the fold growth of M. tb inside monocytes. Our studies demonstrate novel regulatory mechanisms that favor both innate and adaptive control of M. tb infection.

  19. Epinephrine-induced mobilization of natural killer (NK) cells and NK-like T cells in HIV-infected patients

    DEFF Research Database (Denmark)

    Sondergaard, S R; Ullum, H; Skinhoj, P

    1999-01-01

    HIV infection is known to cause changes in phenotype and function of natural killer (NK) cells. The aim of this study was to characterize the NK cells mobilized from peripheral reservoirs in human immunodeficiency virus (HIV)-infected patients and controls. Seventeen HIV-infected patients and eight...... age- and sex-matched controls received a 1-h epinephrine infusion. Epinephrine induced mobilization of high numbers of NK-like T cells with no difference between HIV-infected patients and controls. Interestingly, all subjects mobilized NK cells containing increased proportions of perforin......, in particular the CD3(-)CD16(+)CD56(+) NK cell subset. The HIV-infected patients mobilized CD3(-)CD16(-)CD56(+) and CD3(-)CD16(+)CD56(+) NK cells to a lesser extent than did controls. In contrast, the HIV-infected patients mobilized relatively more CD3(-)CD16(+)CD56(-) NK cells independent of antiretroviral...

  20. Thiolated pyrimidine nucleotides may interfere thiol groups concentrated at lipid rafts of HIV-1 infected cells.

    Science.gov (United States)

    Kanizsai, Szilvia; Ongrádi, Joseph; Aradi, János; Nagy, Károly

    2014-12-01

    Upon HIV infection, cells become activated and cell surface thiols are present in increased number. Earlier we demonstrated in vitro anti-HIV effect of thiolated pyrimidine nucleotide UD29, which interferes thiol function. To further analyse the redox processes required for HIV-1 entry and infection, toxicity assays were performed using HIV-1 infected monolayer HeLaCD4-LTR/ β-gal cells and suspension H9 T cells treated with several thiolated nucleotide derivatives of UD29. Selective cytotoxicity of thiolated pyrimidines on HIV-1 infected cells were observed. Results indicate that thiolated pyrimidine derivates may interfere with -SH (thiol) groups concentrated in lipid rafts of cell membrane and interacts HIV-1 infected (activated) cells resulting in a selective cytotoxicity of HIV-1 infected cells, and reducing HIV-1 entry.

  1. A new in vitro model using small intestinal epithelial cells to enhance infection of Cryptosporidium parvum

    Science.gov (United States)

    To better understand and study the infection of the protozoan parasite Cryptosporidium parvum, a more sensitive in vitro assay is required. In vivo, this parasite infects the epithelial cells of the microvilli layer in the small intestine. While cell infection models using colon,...

  2. Cytotoxic CD4 T Cells: Differentiation, Function, and Application to Dengue Virus Infection

    Directory of Open Access Journals (Sweden)

    Yuan Tian

    2016-12-01

    Full Text Available Dengue virus (DENV has spread through most tropical and subtropical areas of the world and represents a serious public health problem. The control of DENV infection has not yet been fully successful due to lack of effective therapeutics or vaccines. Nevertheless, a better understanding of the immune responses against DENV infection may reveal new strategies for eliciting and improving antiviral immunity. T cells provide protective immunity against various viral infections by generating effector cells that cooperate to eliminate antigens and memory cells that can survive for long periods with enhanced abilities to control recurring pathogens. Following activation, CD8 T cells can migrate to sites of infection and kill infected cells, whereas CD4 T cells contribute to the elimination of pathogens by trafficking to infected tissues and providing help to innate immune responses, B cells, as well as CD8 T cells. However, it is now evident that CD4 T cells can also perform cytotoxic functions and induce the apoptosis of target cells. Importantly, accumulating studies demonstrate that cytotoxic CD4 T cells develop following DENV infections and may play a crucial role in protecting the host from severe dengue disease. We review our current understanding of the differentiation and function of cytotoxic CD4 T cells, with a focus on DENV infection, and discuss the potential of harnessing these cells for the prevention and treatment of DENV infection and disease.

  3. Cytotoxic CD4 T Cells: Differentiation, Function, and Application to Dengue Virus Infection.

    Science.gov (United States)

    Tian, Yuan; Sette, Alessandro; Weiskopf, Daniela

    2016-01-01

    Dengue virus (DENV) has spread through most tropical and subtropical areas of the world and represents a serious public health problem. The control of DENV infection has not yet been fully successful due to lack of effective therapeutics or vaccines. Nevertheless, a better understanding of the immune responses against DENV infection may reveal new strategies for eliciting and improving antiviral immunity. T cells provide protective immunity against various viral infections by generating effector cells that cooperate to eliminate antigens and memory cells that can survive for long periods with enhanced abilities to control recurring pathogens. Following activation, CD8 T cells can migrate to sites of infection and kill infected cells, whereas CD4 T cells contribute to the elimination of pathogens by trafficking to infected tissues and providing help to innate immune responses, B cells, as well as CD8 T cells. However, it is now evident that CD4 T cells can also perform cytotoxic functions and induce the apoptosis of target cells. Importantly, accumulating studies demonstrate that cytotoxic CD4 T cells develop following DENV infections and may play a crucial role in protecting the host from severe dengue disease. We review our current understanding of the differentiation and function of cytotoxic CD4 T cells, with a focus on DENV infection, and discuss the potential of harnessing these cells for the prevention and treatment of DENV infection and disease.

  4. Circulating immune cell subpopulations in pestivirus persistently infected calves and non-infected calves varying in immune status [Abstract

    Science.gov (United States)

    The circulating immune cell subpopulations in cattle representing varying stages of immune status categorized as; colostrum deprived (CD), receiving colostrum (COL), colostrum plus vaccination (VAC) and persistently infected with a pestivirus (PI) were compared. The PI calves were infected with a H...

  5. Circulating immune cell subpopulations in pestivirus persistently infected calves and non-infected calves varying in immune status.

    Science.gov (United States)

    Circulating immune cell subpopulations in cattle representing varying stages of immune status categorized as; colostrum deprived (CD), receiving colostrum (COL), colostrum plus vaccination (VAC) and persistently infected with a pestivirus (PI) were compared. The PI calves were infected with a HoBi-...

  6. Detection of bacteriophage-infected cells of Lactococcus lactis using flow cytometry

    DEFF Research Database (Denmark)

    Michelsen, Ole; Cuesta-Dominguez, Álvaro; Albrektsen, Bjarne;

    2007-01-01

    this change as a consequence of a cease in cell growth, while the ongoing cell divisions leave the cells as single cells. Late in the infection cycle, cells with low-density cell walls appear, and these cells can be detected on cytograms of light scatter versus, for instance, fluorescence of stained DNA. We...

  7. Laser irradiation reduces HIV-1 infection in TZM-bl cells

    CSIR Research Space (South Africa)

    Lugongolo, Masixole Y

    2016-10-01

    Full Text Available HIV-1 epidemic remains a major health challenge. This study explores the effects of low level laser therapy on HIV-1 infected cells. Infection is reduced by irradiation and the mechanism needs to be investigated further....

  8. Host Cell Autophagy in Immune Response to Zoonotic Infections

    Directory of Open Access Journals (Sweden)

    Panagiotis Skendros

    2012-01-01

    Full Text Available Autophagy is a fundamental homeostatic process in which cytoplasmic targets are sequestered within double-membraned autophagosomes and subsequently delivered to lysosomes for degradation. Accumulating evidence supports the pivotal role of autophagy in host defense against intracellular pathogens implicating both innate and adaptive immunity. Many of these pathogens cause common zoonotic infections worldwide. The induction of the autophagic machinery by innate immune receptors signaling, such as TLRs, NOD1/2, and p62/SQSTM1 in antigen-presenting cells results in inhibition of survival and elimination of invading pathogens. Furthermore, Th1 cytokines induce the autophagic process, whereas autophagy also contributes to antigen processing and MHC class II presentation, linking innate to adaptive immunity. However, several pathogens have developed strategies to avoid autophagy or exploit autophagic machinery to their advantage. This paper focuses on the role of host cell autophagy in the regulation of immune response against intracellular pathogens, emphasizing on selected bacterial and protozoan zoonoses.

  9. Altered T cell surface glycosylation in HIV-1 infection results in increased susceptibility to galectin-1-induced cell death.

    Science.gov (United States)

    Lantéri, Marion; Giordanengo, Valérie; Hiraoka, Nobuyoshi; Fuzibet, Jean-Gabriel; Auberger, Patrick; Fukuda, Minoru; Baum, Linda G; Lefebvre, Jean-Claude

    2003-12-01

    The massive T cell death that occurs in HIV type 1 (HIV-1) infection contributes profoundly to the pathophysiology associated with AIDS. The mechanisms controlling cell death of both infected and uninfected T cells ("bystander" death) are not completely understood. We have shown that HIV-1 infection of T cells results in altered glycosylation of cell surface glycoproteins; specifically, it decreased sialylation and increased expression of core 2 O-glycans. Galectin-1 is an endogenous human lectin that recognizes these types of glycosylation changes and induces cell death of activated lymphocytes. Therefore we studied the possible contribution of galectin-1 in the pathophysiology of AIDS. O-glycan modifications were investigated on peripheral lymphocytes from AIDS patients. Oligosaccharides from CD43 and CD45 of CEM cells latently infected with HIV-1 were chemically analyzed. Consistent with our previous results, we show that HIV-1 infection results in accumulation of exposed lactosamine residues, oligosaccharides recognized by galectin-1 on cell surface glycoproteins. Both latently HIV-1-infected T cell lines and peripheral CD4 and CD8 T cells from AIDS patients exhibited exposed lactosamine residues and demonstrated marked susceptibility to galectin-1-induced cell death, in contrast to control cultures or cells from uninfected donors. The fraction of cells that died in response to galectin-1 exceeded the fraction of infected cells, indicating that death of uninfected cells occurred. Altered cell surface glycosylation of T cells during HIV-1 infection increases the susceptibility to galectin-1-induced cell death, and this death pathway can contribute to loss of both infected and uninfected T cells in AIDS.

  10. Activation of naïve NK cells in response to Listeria monocytogenes requires IL-18 and contact with infected dendritic cells1

    OpenAIRE

    Humann, Jessica; Lenz, Laurel L.

    2010-01-01

    The mechanisms for NK cell activation during infection by intracellular bacterial pathogens are not clearly defined. To dissect how Listeria monocytogenes infection elicits NK cell activation, we evaluated the requirements for activation of naïve splenic NK cells by infected bone marrow-derived dendritic cells (BMDC). We found that NK cell activation in this setting required infection of BMDC by live wild-type bacteria. NK cells were not activated when BMDC were infected with a live hemolysin...

  11. Productive infection of human peripheral blood mononuclear cells by feline immunodeficiency virus: implications for vector development.

    Science.gov (United States)

    Johnston, J; Power, C

    1999-03-01

    Feline immunodeficiency virus (FIV) is a lentivirus causing immune suppression and neurological disease in cats. Like primate lentiviruses, FIV utilizes the chemokine receptor CXCR4 for infection. In addition, FIV gene expression has been demonstrated in immortalized human cell lines. To investigate the extent and mechanism by which FIV infected primary and immortalized human cell lines, we compared the infectivity of two FIV strains, V1CSF and Petaluma, after cell-free infection. FIV genome was detected in infected human peripheral blood mononuclear cells (PBMC) and macrophages at 21 and 14 days postinfection, respectively. Flow cytometry analysis of FIV-infected human PBMC indicated that antibodies to FIV p24 recognized 12% of the cells. Antibodies binding the CCR3 chemokine receptor maximally inhibited infection of human PBMC by both FIV strains compared to antibodies to CXCR4 or CCR5. Reverse transcriptase levels increased in FIV-infected human PBMC, with detection of viral titers of 10(1.3) to 10(2.1) 50% tissue culture infective doses/10(6) cells depending on the FIV strain examined. Cell death in human PBMC infected with either FIV strain was significantly elevated relative to uninfected control cultures. These findings indicate that FIV can productively infect primary human cell lines and that viral strain specificity should be considered in the development of an FIV vector for gene therapy.

  12. MHC class Jb-restricted cell responses to Listeria monocytogenes infection.

    Science.gov (United States)

    Kerksiek, K M; Pamer, E G

    1999-12-01

    Murine infection with Listeria monocytogenes induces CD8+ T cell responses specific for bacterial peptides that are presented on the infected cell surface by MHC class Ia and MHC class Ib molecules. We have used MHC tetramers to demonstrate that CD8+ T cells restricted by the H2-M3 MHC class Ib molecules constitute a substantial portion of the T cell response to L. monocytogenes infection. The in vivo size and kinetics of MHC class Ib-restricted T cell populations suggests that they play a prominent role in bacterial clearance following primary L. monocytogenes infection.

  13. Enhanced clearance of HIV-1-infected cells by broadly neutralizing antibodies against HIV-1 in vivo.

    Science.gov (United States)

    Lu, Ching-Lan; Murakowski, Dariusz K; Bournazos, Stylianos; Schoofs, Till; Sarkar, Debolina; Halper-Stromberg, Ariel; Horwitz, Joshua A; Nogueira, Lilian; Golijanin, Jovana; Gazumyan, Anna; Ravetch, Jeffrey V; Caskey, Marina; Chakraborty, Arup K; Nussenzweig, Michel C

    2016-05-20

    Antiretroviral drugs and antibodies limit HIV-1 infection by interfering with the viral life cycle. In addition, antibodies also have the potential to guide host immune effector cells to kill HIV-1-infected cells. Examination of the kinetics of HIV-1 suppression in infected individuals by passively administered 3BNC117, a broadly neutralizing antibody, suggested that the effects of the antibody are not limited to free viral clearance and blocking new infection but also include acceleration of infected cell clearance. Consistent with these observations, we find that broadly neutralizing antibodies can target CD4(+) T cells infected with patient viruses and can decrease their in vivo half-lives by a mechanism that requires Fcγ receptor engagement in a humanized mouse model. The results indicate that passive immunotherapy can accelerate elimination of HIV-1-infected cells.

  14. Role of Bruton’s Tyrosine Kinase inhibitors in HIV-1 infected cells

    Science.gov (United States)

    Guendel, Irene; Iordanskiy, Sergey; Sampey, Gavin C; Van Duyne, Rachel; Calvert, Valerie; Petricoin, Emanuel; Saifuddin, Mohammed; Kehn-Hall, Kylene; Kashanchi, Fatah

    2015-01-01

    Many cellular cofactors have been documented to be critical for various stages of viral replication. Using high throughput proteomic assays, we have previously identified Bruton’s tyrosine kinase (BTK) as a host protein that was uniquely up-regulated in the plasma membrane of HIV-1 infected T-cells. Here, we have further characterized the BTK expression in HIV-1 infection and show that this cellular factor is specifically expressed in infected myeloid cells. Significant up-regulation of the phosphorylated form of BTK was observed in infected cells. Using size exclusion chromatography, we found BTK to be virtually absent in the uninfected U937 cells, however new BTK protein complexes were identified and distributed in both high molecular weight (~600 kDa) and a small molecular weight complex (~60–120 kDa) in the infected U1 cells. BTK levels were highest in cells either chronically expressing virus or induced/infected myeloid cells and that BTK translocated to the membrane following induction of the infected cells. BTK knockdown in HIV-1 infected cells using siRNA resulted in selective death of infected, but not uninfected, cells. Using BTK specific antibody and small molecule inhibitors including LFM-A13 and a FDA approved compound, Ibrutinib (PCI – 32765), we have found that HIV-1 infected cells are sensitive to apoptotic cell death and result in a decrease in virus production. Overall, our data suggests that HIV-1 infected cells are sensitive to treatments targeting BTK expressed in infected cells. PMID:25672887

  15. Role of Bruton's tyrosine kinase inhibitors in HIV-1-infected cells.

    Science.gov (United States)

    Guendel, Irene; Iordanskiy, Sergey; Sampey, Gavin C; Van Duyne, Rachel; Calvert, Valerie; Petricoin, Emanuel; Saifuddin, Mohammed; Kehn-Hall, Kylene; Kashanchi, Fatah

    2015-06-01

    Many cellular cofactors have been documented to be critical for various stages of viral replication. Using high-throughput proteomic assays, we have previously identified Bruton's tyrosine kinase (BTK) as a host protein that was uniquely upregulated in the plasma membrane of human immunodeficiency virus (HIV-1)-infected T cells. Here, we have further characterized the BTK expression in HIV-1 infection and show that this cellular factor is specifically expressed in infected myeloid cells. Significant upregulation of the phosphorylated form of BTK was observed in infected cells. Using size exclusion chromatography, we found BTK to be virtually absent in the uninfected U937 cells; however, new BTK protein complexes were identified and distributed in both high molecular weight (∼600 kDa) and a small molecular weight complex (∼60-120 kDa) in the infected U1 cells. BTK levels were highest in cells either chronically expressing virus or induced/infected myeloid cells and that BTK translocated to the membrane following induction of the infected cells. BTK knockdown in HIV-1-infected cells using small interfering RNA (siRNA) resulted in selective death of infected, but not uninfected, cells. Using BTK-specific antibody and small-molecule inhibitors including LFM-A13 and a FDA-approved compound, ibrutinib (PCI-32765), we have found that HIV-1-infected cells are sensitive to apoptotic cell death and result in a decrease in virus production. Overall, our data suggests that HIV-1-infected cells are sensitive to treatments targeting BTK expressed in infected cells.

  16. Monkeypox virus infection of rhesus macaques induces massive expansion of natural killer cells but suppresses natural killer cell functions.

    Directory of Open Access Journals (Sweden)

    Haifeng Song

    Full Text Available Natural killer (NK cells play critical roles in innate immunity and in bridging innate and adaptive immune responses against viral infection. However, the response of NK cells to monkeypox virus (MPXV infection is not well characterized. In this intravenous challenge study of MPXV infection in rhesus macaques (Macaca mulatta, we analyzed blood and lymph node NK cell changes in absolute cell numbers, cell proliferation, chemokine receptor expression, and cellular functions. Our results showed that the absolute number of total NK cells in the blood increased in response to MPXV infection at a magnitude of 23-fold, manifested by increases in CD56+, CD16+, CD16-CD56- double negative, and CD16+CD56+ double positive NK cell subsets. Similarly, the frequency and NK cell numbers in the lymph nodes also largely increased with the total NK cell number increasing 46.1-fold. NK cells both in the blood and lymph nodes massively proliferated in response to MPXV infection as measured by Ki67 expression. Chemokine receptor analysis revealed reduced expression of CXCR3, CCR7, and CCR6 on NK cells at early time points (days 2 and 4 after virus inoculation, followed by an increased expression of CXCR3 and CCR5 at later time points (days 7-8 of infection. In addition, MPXV infection impaired NK cell degranulation and ablated secretion of interferon-γ and tumor necrosis factor-α. Our data suggest a dynamic model by which NK cells respond to MPXV infection of rhesus macaques. Upon virus infection, NK cells proliferated robustly, resulting in massive increases in NK cell numbers. However, the migrating capacity of NK cells to tissues at early time points might be reduced, and the functions of cytotoxicity and cytokine secretion were largely compromised. Collectively, the data may explain, at least partially, the pathogenesis of MPXV infection in rhesus macaques.

  17. Chlamydia trachomatis Infection of Endocervical Epithelial Cells Enhances Early HIV Transmission Events.

    Science.gov (United States)

    Buckner, Lyndsey R; Amedee, Angela M; Albritton, Hannah L; Kozlowski, Pamela A; Lacour, Nedra; McGowin, Chris L; Schust, Danny J; Quayle, Alison J

    2016-01-01

    Chlamydia trachomatis causes a predominantly asymptomatic, but generally inflammatory, genital infection that is associated with an increased risk for HIV acquisition. Endocervical epithelial cells provide the major niche for this obligate intracellular bacterium in women, and the endocervix is also a tissue in which HIV transmission can occur. The mechanism by which CT infection enhances HIV susceptibility at this site, however, is not well understood. Utilizing the A2EN immortalized endocervical epithelial cell line grown on cell culture inserts, we evaluated the direct role that CT-infected epithelial cells play in facilitating HIV transmission events. We determined that CT infection significantly enhanced the apical-to-basolateral migration of cell-associated, but not cell-free, HIVBaL, a CCR5-tropic strain of virus, across the endocervical epithelial barrier. We also established that basolateral supernatants from CT-infected A2EN cells significantly enhanced HIV replication in peripheral mononuclear cells and a CCR5+ T cell line. These results suggest that CT infection of endocervical epithelial cells could facilitate both HIV crossing the mucosal barrier and subsequent infection or replication in underlying target cells. Our studies provide a mechanism by which this common STI could potentially promote the establishment of founder virus populations and the maintenance of local HIV reservoirs in the endocervix. Development of an HIV/STI co-infection model also provides a tool to further explore the role of other sexually transmitted infections in enhancing HIV acquisition.

  18. Modelling and analysis of dynamics of viral infection of cells and of interferon resistance

    Science.gov (United States)

    Getto, Ph.; Kimmel, M.; Marciniak-Czochra, A.

    2008-08-01

    Interferons are active biomolecules, which help fight viral infections by spreading from infected to uninfected cells and activate effector molecules, which confer resistance from the virus on cells. We propose a new model of dynamics of viral infection, including endocytosis, cell death, production of interferon and development of resistance. The novel element is a specific biologically justified mechanism of interferon action, which results in dynamics different from other infection models. The model reflects conditions prevailing in liquid cultures (ideal mixing), and the absence of cells or virus influx from outside. The basic model is a nonlinear system of five ordinary differential equations. For this variant, it is possible to characterise global behaviour, using a conservation law. Analytic results are supplemented by computational studies. The second variant of the model includes age-of-infection structure of infected cells, which is described by a transport-type partial differential equation for infected cells. The conclusions are: (i) If virus mortality is included, the virus becomes eventually extinct and subpopulations of uninfected and resistant cells are established. (ii) If virus mortality is not included, the dynamics may lead to extinction of uninfected cells. (iii) Switching off the interferon defense results in a decrease of the sum total of uninfected and resistant cells. (iv) Infection-age structure of infected cells may result in stabilisation or destabilisation of the system, depending on detailed assumptions. Our work seems to constitute the first comprehensive mathematical analysis of the cell-virus-interferon system based on biologically plausible hypotheses.

  19. Metabolic effects of influenza virus infection in cultured animal cells: Intra- and extracellular metabolite profiling

    Directory of Open Access Journals (Sweden)

    Genzel Yvonne

    2010-05-01

    Full Text Available Abstract Background Many details in cell culture-derived influenza vaccine production are still poorly understood and approaches for process optimization mainly remain empirical. More insights on mammalian cell metabolism after a viral infection could give hints on limitations and cell-specific virus production capacities. A detailed metabolic characterization of an influenza infected adherent cell line (MDCK was carried out based on extracellular and intracellular measurements of metabolite concentrations. Results For most metabolites the comparison of infected (human influenza A/PR/8/34 and mock-infected cells showed a very similar behavior during the first 10-12 h post infection (pi. Significant changes were observed after about 12 h pi: (1 uptake of extracellular glucose and lactate release into the cell culture supernatant were clearly increased in infected cells compared to mock-infected cells. At the same time (12 h pi intracellular metabolite concentrations of the upper part of glycolysis were significantly increased. On the contrary, nucleoside triphosphate concentrations of infected cells dropped clearly after 12 h pi. This behaviour was observed for two different human influenza A/PR/8/34 strains at slightly different time points. Conclusions Comparing these results with literature values for the time course of infection with same influenza strains, underline the hypothesis that influenza infection only represents a minor additional burden for host cell metabolism. The metabolic changes observed after12 h pi are most probably caused by the onset of apoptosis in infected cells. The comparison of experimental data from two variants of the A/PR/8/34 virus strain (RKI versus NIBSC with different productivities and infection dynamics showed comparable metabolic patterns but a clearly different timely behavior. Thus, infection dynamics are obviously reflected in host cell metabolism.

  20. Canine distemper virus epithelial cell infection is required for clinical disease but not for immunosuppression.

    Science.gov (United States)

    Sawatsky, Bevan; Wong, Xiao-Xiang; Hinkelmann, Sarah; Cattaneo, Roberto; von Messling, Veronika

    2012-04-01

    To characterize the importance of infection of epithelial cells for morbillivirus pathogenesis, we took advantage of the severe disease caused by canine distemper virus (CDV) in ferrets. To obtain a CDV that was unable to enter epithelial cells but retained the ability to enter immune cells, we transferred to its attachment (H) protein two mutations shown to interfere with the interaction of measles virus H with its epithelial receptor, human nectin-4. As expected for an epithelial receptor (EpR)-blind CDV, this virus infected dog and ferret epithelial cells inefficiently and did not cause cell fusion or syncytium formation. On the other hand, the EpR-blind CDV replicated in cells expressing canine signaling lymphocyte activation molecule (SLAM), the morbillivirus immune cell receptor, with similar kinetics to those of wild-type CDV. While ferrets infected with wild-type CDV died within 12 days after infection, after developing severe rash and fever, animals infected with the EpR-blind virus showed no clinical signs of disease. Nevertheless, both viruses spread rapidly and efficiently in immune cells, causing similar levels of leukopenia and inhibition of lymphocyte proliferation activity, two indicators of morbillivirus immunosuppression. Infection was documented for airway epithelia of ferrets infected with wild-type CDV but not for those of animals infected with the EpR-blind virus, and only animals infected with wild-type CDV shed virus. Thus, epithelial cell infection is necessary for clinical disease and efficient virus shedding but not for immunosuppression.

  1. The central role of the CD4 T-helper cell in HIV infection : Analysis of cell mediated responses and CCR-5 genotypes in HIV-1 infected individuals

    OpenAIRE

    2001-01-01

    Human immunodeficiency virus (HIV) infection is characterized by progressive immunologic dysregulation. The main target of HIV is the CD4 cell resulting in malfunction of the immune system, with a decline in CD4 cells and subsequent development of the acquired immunodeficiency syndrome (AIDS). HIV-infected individuals show impaired responses to antigenic stimulation, particularly to HIV proteins, even before a significant decline in the number of CD4 cells is observed. T...

  2. DIESEL EXHAUST ENHANCES INFLUENZA VIRUS INFECTIONS IN RESPIRATORY EPITHELIAL CELLS

    Science.gov (United States)

    Several factors, such as age and nutritional status can affect the susceptibility to influenza infections. Moreover, exposure to air pollutants, such as diesel exhaust (DE), has been shown to affect respiratory virus infections in rodent models. Influenza virus primarily infects ...

  3. DIESEL EXHAUST ENHANCES INFLUENZA VIRUS INFECTIONS IN RESPIRATORY EPITHELIAL CELLS

    Science.gov (United States)

    Several factors, such as age and nutritional status can affect the susceptibility to influenza infections. Moreover, exposure to air pollutants, such as diesel exhaust (DE), has been shown to affect respiratory virus infections in rodent models. Influenza virus primarily infects ...

  4. Saffold virus is able to productively infect primate and rodent cell lines and induces apoptosis in these cells.

    Science.gov (United States)

    Xu, Yishi; Victorio, Carla Bianca Luena; Ng, Qimei; Tan, Yee Joo; Chua, Kaw Bing

    2014-02-01

    Saffold virus (SAFV), a newly discovered human cardiovirus of the Picornaviridae family, causes widespread infection among children, as shown by previous seroprevalence studies. To determine the host cell range of SAFV and its cytopathogenicity, eight mammalian cell lines that were available in the laboratory were screened for productive SAFV infection by a laboratory-adapted SAFV of genotype 3. Five of the cell lines (Neuro2A, CHO-K1, NIH/3T3, Vero and HEp-2) were found to be permissible. The time required for SAFV to induce complete lysis as a cytopathic effect (CPE) in these permissibly infected cells and the resultant end point virus titer differed for each cell type. HEp-2 exhibited the shortest time frame to reach full CPE compared to the others. All infected cell lines produced a high virus titer at 72 h post-infection. In addition to causing lytic cell death, SAFV also induced apoptotic cell death in host cells through both extrinsic and intrinsic pathways, although the apoptotic events in HEp-2 cells appeared to have been blocked between the early and late stages. In conclusion, laboratory-adapted SAFV is able to productively infect a number of mammalian cell lines and induce apoptosis in the infected host cells. However, apoptosis in HEp-2 cells is blocked before the end stage.

  5. Selective destruction of cells infected with human immunodeficiency virus

    Science.gov (United States)

    Keener, William K.; Ward, Thomas E.

    2003-09-30

    Compositions and methods for selectively killing a cell containing a viral protease are disclosed. The composition is a variant of a protein synthesis inactivating toxin wherein a viral protease cleavage site is interposed between the A and B chains. The variant of the type II ribosome-inactivating protein is activated by digestion of the viral protease cleavage site by the specific viral protease. The activated ribosome-inactivating protein then kills the cell by inactivating cellular ribosomes. A preferred embodiment of the invention is specific for human immunodeficiency virus (HIV) and uses ricin as the ribosome-inactivating protein. In another preferred embodiment of the invention, the variant of the ribosome-inactivating protein is modified by attachment of one or more hydrophobic agents. The hydrophobic agent facilitates entry of the variant of the ribosome-inactivating protein into cells and can lead to incorporation of the ribosome-inactivating protein into viral particles. Still another preferred embodiment of the invention includes a targeting moiety attached to the variants of the ribosome-inactivating protein to target the agent to HIV infectable cells.

  6. Selective Destruction Of Cells Infected With The Human Immunodeficiency Virus

    Science.gov (United States)

    Keener, William K.; Ward, Thomas E.

    2006-03-28

    Compositions and methods for selectively killing a cell containing a viral protease are disclosed. The composition is a varient of a protein synthesis inactivating toxin wherein a viral protease cleavage site is interposed between the A and B chains. The variant of the type II ribosome-inactivating protein is activated by digestion of the viral protease cleavage site by the specific viral protease. The activated ribosome-inactivating protein then kills the cell by inactivating cellular ribosomes. A preferred embodiment of the invention is specific for human immunodeficiency virus (HIV) and uses ricin as the ribosome-inactivating protein. In another preferred embodiment of the invention, the variant of the ribosome-inactivating protein is modified by attachment of one or more hydrophobic agents. The hydrophobic agent facilitates entry of the variant of the ribosome-inactivating protein into cells and can lead to incorporation of the ribosome-inactivating protein into viral particles. Still another preferred embodiment of the invention includes a targeting moiety attached to the variants of the ribosome-inactivating protein to target the agent to HIV infectable cells.

  7. Endothelial cell death and intimal foam cell accumulation in the coronary artery of infected hypercholesterolemic minipigs

    DEFF Research Database (Denmark)

    Birck, Malene Muusfeldt; Saraste, Antti; Hyttel, Poul

    2013-01-01

    Apoptosis of endothelial cells (ECs) has been suggested to play a role in atherosclerosis. We studied the synergism of hypercholesterolemia with Chlamydia pneumoniae and influenza virus infections on EC morphology and intimal changes in a minipig model. The coronary artery was excised at euthanasia...

  8. Plasmacytoid dendritic cells are crucial in Bifidobacterium adolescentis-mediated inhibition of Yersinia enterocolitica infection.

    Science.gov (United States)

    Wittmann, Alexandra; Autenrieth, Ingo B; Frick, Julia-Stefanie

    2013-01-01

    In industrialized countries bacterial intestinal infections are commonly caused by enteropathogenic Enterobacteriaceae. The interaction of the microbiota with the host immune system determines the adequacy of an appropriate response against pathogens. In this study we addressed whether the probiotic Bifidobacterium adolescentis is protective during intestinal Yersinia enterocolitica infection. Female C57BL/6 mice were fed with B. adolescentis, infected with Yersinia enterocolitica, or B. adolescentis fed and subsequently infected with Yersinia enterocolitica. B. adolescentis fed and Yersinia infected mice were protected from Yersinia infection as indicated by a significantly reduced weight loss and splenic Yersinia load when compared to Yersinia infected mice. Moreover, protection from infection was associated with increased intestinal plasmacytoid dendritic cell and regulatory T-cell frequencies. Plasmacytoid dendritic cell function was investigated using depletion experiments by injecting B. adolescentis fed, Yersinia infected C57BL/6 mice with anti-mouse PDCA-1 antibody, to deplete plasmacytoid dendritic cells, or respective isotype control. The B. adolescentis-mediated protection from Yersinia dissemination to the spleen was abrogated after plasmacytoid dendritic cell depletion indicating a crucial function for pDC in control of intestinal Yersinia infection. We suggest that feeding of B. adolescentis modulates the intestinal immune system in terms of increased plasmacytoid dendritic cell and regulatory T-cell frequencies, which might account for the B. adolescentis-mediated protection from Yersinia enterocolitica infection.

  9. Changes in Natural Killer cell activation and function during primary HIV-1 Infection.

    Directory of Open Access Journals (Sweden)

    Vivek Naranbhai

    Full Text Available BACKGROUND: Recent reports suggest that Natural Killer (NK cells may modulate pathogenesis of primary HIV-1 infection. However, HIV dysregulates NK-cell responses. We dissected this bi-directional relationship to understand how HIV impacts NK-cell responses during primary HIV-1 infection. METHODOLOGY/PRINCIPAL FINDINGS: Paired samples from 41 high-risk, initially HIV-uninfected CAPRISA004 participants were analysed prior to HIV acquisition, and during viraemic primary HIV-1 infection. At the time of sampling post-infection five women were seronegative, 11 women were serodiscordant, and 25 women were seropositive by HIV-1 rapid immunoassay. Flow cytometry was used to measure NK and T-cell activation, NK-cell receptor expression, cytotoxic and cytokine-secretory functions, and trafficking marker expression (CCR7, α(4β(7. Non-parametric statistical tests were used. Both NK cells and T-cells were significantly activated following HIV acquisition (p = 0.03 and p<0.0001, respectively, but correlation between NK-cell and T-cell activation was uncoupled following infection (pre-infection r = 0.68;p<0.0001; post-infection, during primary infection r = 0.074;p = 0.09. Nonetheless, during primary infection NK-cell and T-cell activation correlated with HIV viral load (r = 0.32'p = 0.04 and r = 0.35;p = 0.02, respectively. The frequency of Killer Immunoglobulin-like Receptor-expressing (KIR(pos NK cells increased following HIV acquisition (p = 0.006, and KIR(pos NK cells were less activated than KIR(neg NK cells amongst individuals sampled while seronegative or serodiscordant (p = 0.001;p<0.0001 respectively. During HIV-1 infection, cytotoxic NK cell responses evaluated after IL-2 stimulation alone, or after co-culture with 721 cells, were impaired (p = 0.006 and p = 0.002, respectively. However, NK-cell IFN-y secretory function was not significantly altered. The frequency of CCR7+ NK cells was elevated

  10. [Significance of detecting the EBV-DNA level in peripheral blood mononuclear cells and the EBV-infected cell type in patients with chronic active EBV infection].

    Science.gov (United States)

    Xing, Yan; Song, Hong-mei; Wu, Xiao-yan; Wang, Wei; Wei, Min

    2011-07-01

    To study the difference in the EBV-DNA level in peripheral blood mononuclear cells (PBMC) and the type of Epstein-Barr virus (EBV)-infected cells in pediatric patients with chronic active EBV (CAEBV) infection, acute EBV infection (AEBV) and healthy children, and to analyze the relationship between the above difference and the clinical manifestation of CAEBV. Real-time fluorescent quantitative polymerase chain reaction (PCR) was used to detect the EBV-DNA levels in peripheral blood mononuclear cells (PBMC) in 12 normal children, 10 pediatric patients with CAEBV infection and 13 pediatric patients with AEBV infection in our hospital between March 2004 and April 2008. Immunomagnetic bead cell fractionation and fluorescent in situ hybridization (FISH) by EBV encoding RNA-1 ( EBER-1) probe were used in the healthy children, EBV-DNA positive CAEBV patients and AEBV patients to detect the type of EBV-infected cells. The average EBV-DNA level in CAEBV patients' PBMC was (6.8 x 10(7) +/- 1.1 x 10(8)) copies/ml, while the average EBV-DNA level of AEBV patients' PBMC was (1.3 x 10(6) +/- 1.6 x 10(6)) copies/ml. The average EBV-DNA level of CAEBV infected patients' PBMC was significantly higher than that of AEBV infected patients' PBMC (Pblood cells. In 1 CAEBV patient the infection was mainly found in NK cells, who presented with hypersensitivity to mosquito biting and high IgE level (2500 U/ml). But EBV in seven AEBV patients infection was found only in B cells who presented with only IM for one time and no EBV-infected PBMC were found in the remaining 6 healthy children. There are much more EBV replications and different EBV-infected cell types in CAEBV patients. Detection of EBV-DNA level by real-time fluorescent quantitative PCR and the detection of the type of EBV-infected cells may help in diagnosis, treatment and development evaluation of children with CAEBV infection.

  11. Depletion of CD8+ cells does not affect the lifespan of productively infected cells during pathogenic sivmac239 infection of rhesus macaques

    Energy Technology Data Exchange (ETDEWEB)

    Shudo, Emi [Los Alamos National Laboratory; Ribeiro, Ruy M [Los Alamos National Laboratory; Perelson, Alan S [Los Alamos National Laboratory

    2008-01-01

    While CD8+ T cell responses are clearly important in anti-viral immunity during HIV/SIV infection, the mechanisms by which CD8+ T cells induce this effect remain poorly understood, as emphasized by the failure of the Merck adenovirus-based, cytotoxic T lymphocyte (CTL)-inducing AIDS vaccine in a large phase IIb clinical trial. In this study, we measured the in vivo effect of CD8+ lymphocytes on the lifespan of productively infected cells during chronic SIVmac239 infection of rhesus macaques by treating two groups of animals (i.e., CD8+ lymphocyte-depleted or controls) with antiretroviral therapy (PMPA and FTC). The lifespan of productively infected cells was calculated based on the slope of the decline of SIV plasma viremia using a well-accepted mathematical model. We found that, in both early (i.e., day 57 post-inoculation) and late (i.e., day 177 post-inoculation) chronic SIV infection, depletion of CD8+ lymphocytes did not result in an increased lifespan of productively infected cells in vivo. This result indicates that direct killing of cells producing virus is unlikely to be a major mechanism underlying the anti-viral effect of CD8+ T cells during SIV infection. These results have profound implications for the development of AIDS vaccines.

  12. Cell-to-cell contact of human monocytes with infected arterial smooth-muscle cells enhances growth of Chlamydia pneumoniae.

    Science.gov (United States)

    Puolakkainen, Mirja; Campbell, Lee Ann; Lin, Tsun-Mei; Richards, Theresa; Patton, Dorothy L; Kuo, Cho-Chou

    2003-02-01

    Chlamydia pneumoniae can infect arterial cells. It has been shown that coculture of human monocytes (U937) and endothelial cells promotes infection of C. pneumoniae in endothelial cells and that the enhancement was mediated by a soluble factor (insulin-like growth factor 2) secreted by monocytes. In this study, it is shown that coculture of monocytes with C. pneumoniae enhances infection of C. pneumoniae in arterial smooth-muscle cells 5.3-fold at a monocyte-to-smooth-muscle cell ratio of 5. However, unlike endothelial cells, no enhancement was observed if monocytes were placed in cell culture inserts or if conditioned medium from monocyte cultures was used, which suggests that cell-to-cell contact is critical. The addition of mannose 6-phosphate or octyl glucoside, a nonionic detergent containing a sugar group, to cocultures inhibited the enhancement. These findings suggest that the monocyte-smooth-muscle cell interaction may be mediated by mannose 6-phosphate receptors present on monocytes.

  13. Propofol Increases Host Susceptibility to Microbial Infection by Reducing Subpopulations of Mature Immune Effector Cells at Sites of Infection

    Science.gov (United States)

    Visvabharathy, Lavanya; Xayarath, Bobbi; Weinberg, Guy; Shilling, Rebecca A.; Freitag, Nancy E.

    2015-01-01

    Anesthetics are known to modulate host immune responses, but separating the variables of surgery from anesthesia when analyzing hospital acquired infections is often difficult. Here, the bacterial pathogen Listeria monocytogenes (Lm) was used to assess the impact of the common anesthetic propofol on host susceptibility to infection. Brief sedation of mice with physiologically relevant concentrations of propofol increased bacterial burdens in target organs by more than 10,000-fold relative to infected control animals. The adverse effects of propofol sedation on immune clearance of Lm persisted after recovery from sedation, as animals given the drug remained susceptible to infection for days following anesthesia. In contrast to propofol, sedation with alternative anesthetics such as ketamine/xylazine or pentobarbital did not increase susceptibility to systemic Lm infection. Propofol altered systemic cytokine and chemokine expression during infection, and prevented effective bacterial clearance by inhibiting the recruitment and/or activity of immune effector cells at sites of infection. Propofol exposure induced a marked reduction in marginal zone macrophages in the spleens of Lm infected mice, resulting in bacterial dissemination into deep tissue. Propofol also significantly increased mouse kidney abscess formation following infection with the common nosocomial pathogen Staphylococcus aureus. Taken together, these data indicate that even brief exposure to propofol severely compromises host resistance to microbial infection for days after recovery from sedation. PMID:26381144

  14. Propofol Increases Host Susceptibility to Microbial Infection by Reducing Subpopulations of Mature Immune Effector Cells at Sites of Infection.

    Directory of Open Access Journals (Sweden)

    Lavanya Visvabharathy

    Full Text Available Anesthetics are known to modulate host immune responses, but separating the variables of surgery from anesthesia when analyzing hospital acquired infections is often difficult. Here, the bacterial pathogen Listeria monocytogenes (Lm was used to assess the impact of the common anesthetic propofol on host susceptibility to infection. Brief sedation of mice with physiologically relevant concentrations of propofol increased bacterial burdens in target organs by more than 10,000-fold relative to infected control animals. The adverse effects of propofol sedation on immune clearance of Lm persisted after recovery from sedation, as animals given the drug remained susceptible to infection for days following anesthesia. In contrast to propofol, sedation with alternative anesthetics such as ketamine/xylazine or pentobarbital did not increase susceptibility to systemic Lm infection. Propofol altered systemic cytokine and chemokine expression during infection, and prevented effective bacterial clearance by inhibiting the recruitment and/or activity of immune effector cells at sites of infection. Propofol exposure induced a marked reduction in marginal zone macrophages in the spleens of Lm infected mice, resulting in bacterial dissemination into deep tissue. Propofol also significantly increased mouse kidney abscess formation following infection with the common nosocomial pathogen Staphylococcus aureus. Taken together, these data indicate that even brief exposure to propofol severely compromises host resistance to microbial infection for days after recovery from sedation.

  15. Establishment of persistent foot-and-mouth disease virus (FMDV) infection in MDBK cells.

    Science.gov (United States)

    Kopliku, Lela; Relmy, Anthony; Romey, Aurore; Gorna, Kamila; Zientara, Stephan; Bakkali-Kassimi, Labib; Blaise-Boisseau, Sandra

    2015-10-01

    In addition to acute infection and disease, foot-and-mouth disease virus (FMDV) can cause persistent infection in ruminants. Such "carrier" animals represent a potential risk for FMDV transmission to susceptible animals. However, the mechanisms and the factors that determine FMDV persistence remain unknown. We describe here the establishment of FMDV type O persistent infection in a bovine epithelial cell line (Madin-Darby bovine kidney; MDBK). Preliminary experiments to assess the permissivity of MDBK cells to FMDV O infection revealed an unusual pattern of infection: after the initial phase of acute cell lysis, new monolayers formed within 48-72 h post-infection. We found that some cells survived cytolytic infection and subsequently regrew, thereby demonstrating that this bovine cell line can be persistently infected with FMDV type O. Further evidence that MDBK cells were persistently infected with FMDV includes: (i) detection of viral RNA in cells as well as in cell culture supernatants, (ii) detection of viral antigens in the cells by immunofluorescence analysis, and (iii) production of infectious viral particles for up to 36 cell passages. Furthermore, preliminary sequence analysis of persistent virus revealed a single nucleotide substitution within the VP1 coding region, resulting in the V50A amino acid substitution. This bovine model of FMDV persistence holds promise for the investigation of the viral and cellular molecular determinants that promote FMDV persistence.

  16. Different Responses of Two Highly Permissive Cell Lines Upon HCV Infection

    Institute of Scientific and Technical Information of China (English)

    Honghe Chen; Rongjuan Pei; Xinwen Chen

    2013-01-01

    The construction of the first infectious clone JFH-1 speeds up the research on hepatitis C virus (HCV).However,Huh7 cell line was the only highly permissive cell line for HCV infection and only a few clones were fully permissive.In this study,two different fully permissive clones of Huh7 cells,Huh7.5.1 and Huh7-Lunet-CD81 (Lunet-CD81) cells were compared for their responses upon HCV infection.The virus replication level was found slightly higher in Huh7.5.1 cells than that in Lunet-CD81 cells.Viability of Huh7.5.1 cells but not of Lunet-CD81 cells was reduced significantly after HCV infection.Further analysis showed that the cell cycle of infected Huh7.5.1 cells was arrested at G1 phase.The G1/S transition was blocked by HCV infection in Huh7.5.1 cells as shown by the cell cycle synchronization analysis.Genes related to cell cycle regulation was modified by HCV infection and gene interaction analysis in GeneSpring GX in Direct Interactions mode highlighted 31 genes.In conclusion,the responses of those two cell lines were different upon HCV infection.HCV infection blocked G1/S transition and cell cycle progress,thus reduced the cell viability in Huh7.5.1 cells but not in Lunet-CD81 cells.Lunet-CD81 cells might be suitable for long term infection studies of HCV.

  17. Targeting host syntaxin-5 preferentially blocks Leishmania parasitophorous vacuole development in infected cells and limits experimental Leishmania infections.

    Science.gov (United States)

    Canton, Johnathan; Kima, Peter E

    2012-10-01

    Our previous observations established a role for syntaxin-5 in the development of Leishmania parasitophorous vacuoles (LPVs). In this study, we took advantage of the recent identification of Retro-2, a small organic molecule that can cause the redistribution of syntaxin-5; we show herein that Retro-2 blocks LPV development within 2 hours of adding it to cells infected with Leishmania amazonensis. In infected cells incubated for 48 hours with Retro-2, LPV development was significantly limited; furthermore, infected cells harbored four to five times fewer parasites than infected cells incubated in vehicle alone. In vivo studies revealed that Retro-2 curbed experimental L. amazonensis infections in a dose-dependent manner. Retro-2 did not have any appreciable effect on the host cell physiological characteristics; furthermore, it had no apparent toxicity in experimental animals. An unexpected, but welcome, finding was that Retro-2 inhibited the replication of Leishmania parasites in axenic cultures. This study is significant because it identifies an endoplasmic reticulum/Golgi SNARE as a potential target for the control of Leishmania infections; moreover, it suggests that small organic molecules can be identified that can selectively disrupt the vesicle fusion machinery that promotes the development of pathogen-containing compartments without exerting toxic effects on the host.

  18. Intrahepatic infiltrating NK and CD8 T cells cause liver cell death in different phases of dengue virus infection.

    Science.gov (United States)

    Sung, Jui-Min; Lee, Chien-Kuo; Wu-Hsieh, Betty A

    2012-01-01

    Elevated liver enzyme level is an outstanding feature in patients with dengue. However, the pathogenic mechanism of liver injury has not been clearly demonstrated. In this study, employing a mouse model we aimed to investigate the immunopathogenic mechanism of dengue liver injury. Immunocompetent C57BL/6 mice were infected intravenously with dengue virus strain 16681. Infected mice had transient viremia, detectable viral capsid gene and cleaved caspase 3 in the liver. In the mean time, NK cell and T cell infiltrations peaked at days 1 and 5, respectively. Neutralizing CXCL10 or depletion of Asialo GM1(+) cells reduced cleaved caspase 3 and TUNEL(+) cells in the liver at day 1 after infection. CD8(+) T cells infiltrated into the liver at later time point and at which time intrahepatic leukocytes (IHL) exhibited cytotoxicity against DENV-infected targets. Cleaved caspase 3 and TUNEL(+) cells were diminished in mice with TCRβ deficiency and in those depleted of CD8(+) T cells, respectively, at day 5 after infection. Moreover, intrahepatic CD8(+) T cells were like their splenic counterparts recognized DENV NS4B(99-107) peptide. Together, these results show that infiltrating NK and CD8(+) T cells cause liver cell death. While NK cells were responsible for cell death at early time point of infection, CD8(+) T cells were for later. CD8(+) T cells that recognize NS4B(99-107) constitute at least one of the major intrahepatic cytotoxic CD8(+) T cell populations.

  19. Intrahepatic infiltrating NK and CD8 T cells cause liver cell death in different phases of dengue virus infection.

    Directory of Open Access Journals (Sweden)

    Jui-Min Sung

    Full Text Available Elevated liver enzyme level is an outstanding feature in patients with dengue. However, the pathogenic mechanism of liver injury has not been clearly demonstrated. In this study, employing a mouse model we aimed to investigate the immunopathogenic mechanism of dengue liver injury. Immunocompetent C57BL/6 mice were infected intravenously with dengue virus strain 16681. Infected mice had transient viremia, detectable viral capsid gene and cleaved caspase 3 in the liver. In the mean time, NK cell and T cell infiltrations peaked at days 1 and 5, respectively. Neutralizing CXCL10 or depletion of Asialo GM1(+ cells reduced cleaved caspase 3 and TUNEL(+ cells in the liver at day 1 after infection. CD8(+ T cells infiltrated into the liver at later time point and at which time intrahepatic leukocytes (IHL exhibited cytotoxicity against DENV-infected targets. Cleaved caspase 3 and TUNEL(+ cells were diminished in mice with TCRβ deficiency and in those depleted of CD8(+ T cells, respectively, at day 5 after infection. Moreover, intrahepatic CD8(+ T cells were like their splenic counterparts recognized DENV NS4B(99-107 peptide. Together, these results show that infiltrating NK and CD8(+ T cells cause liver cell death. While NK cells were responsible for cell death at early time point of infection, CD8(+ T cells were for later. CD8(+ T cells that recognize NS4B(99-107 constitute at least one of the major intrahepatic cytotoxic CD8(+ T cell populations.

  20. Inhibition of apoptosis in neuronal cells infected with Chlamydophila (Chlamydia pneumoniae

    Directory of Open Access Journals (Sweden)

    Albert Elizabeth V

    2008-01-01

    Full Text Available Abstract Background Chlamydophila (Chlamydia pneumoniae is an intracellular bacterium that has been identified within cells in areas of neuropathology found in Alzheimer disease (AD, including endothelia, glia, and neurons. Depending on the cell type of the host, infection by C. pneumoniae has been shown to influence apoptotic pathways in both pro- and anti-apoptotic fashions. We have hypothesized that persistent chlamydial infection of neurons may be an important mediator of the characteristic neuropathology observed in AD brains. Chronic and/or persistent infection of neuronal cells with C. pneumoniae in the AD brain may affect apoptosis in cells containing chlamydial inclusions. Results SK-N-MC neuroblastoma cells were infected with the respiratory strain of C. pneumoniae, AR39 at an MOI of 1. Following infection, the cells were either untreated or treated with staurosporine and then examined for apoptosis by labeling for nuclear fragmentation, caspase activity, and membrane inversion as indicated by annexin V staining. C. pneumoniae infection was maintained through 10 days post-infection. At 3 and 10 days post-infection, the infected cell cultures appeared to inhibit or were resistant to the apoptotic process when induced by staurosporine. This inhibition was demonstrated quantitatively by nuclear profile counts and caspase 3/7 activity measurements. Conclusion These data suggest that C. pneumoniae can sustain a chronic infection in neuronal cells by interfering with apoptosis, which may contribute to chronic inflammation in the AD brain.

  1. Macrophages are required for dendritic cell uptake of respiratory syncytial virus from an infected epithelium.

    Science.gov (United States)

    Ugonna, Kelechi; Bingle, Colin D; Plant, Karen; Wilson, Kirsty; Everard, Mark L

    2014-01-01

    We have previously shown that the respiratory syncytial virus [RSV] can productively infect monocyte derived dendritic cells [MoDC] and remain dormant within the same cells for prolonged periods. It is therefore possible that infected dendritic cells act as a reservoir within the airways of individuals between annual epidemics. In the present study we explored the possibility that sub-epithelial DCs can be infected with RSV from differentiated bronchial epithelium and that in turn RSV from DCs can infect the epithelium. A dual co-culture model was established in which a differentiated primary airway epithelium on an Air Liquid Interface (ALI) was cultured on a transwell insert and MoDCs were subsequently added to the basolateral membrane of the insert. Further experiments were undertaken using a triple co-culture model in which in which macrophages were added to the apical surface of the differentiated epithelium. A modified RSV [rr-RSV] expressing a red fluorescent protein marker of replication was used to infect either the MoDCs or the differentiated epithelium and infection of the reciprocal cell type was assessed using confocal microscopy. Our data shows that primary epithelium became infected when rr-RSV infected MoDCs were introduced onto the basal surface of the transwell insert. MoDCs located beneath the epithelium did not become infected with virus from infected epithelial cells in the dual co-culture model. However when macrophages were present on the apical surface of the primary epithelium infection of the basal MoDCs occurred. Our data suggests that RSV infected dendritic cells readily transmit infection to epithelial cells even when they are located beneath the basal layer. However macrophages appear to be necessary for the transmission of infection from epithelial cells to basal dendritic cells.

  2. Intracellular cytokine production by dengue virus-specific T cells correlates with subclinical secondary infection.

    Science.gov (United States)

    Hatch, Steven; Endy, Tim P; Thomas, Stephen; Mathew, Anuja; Potts, James; Pazoles, Pamela; Libraty, Daniel H; Gibbons, Robert; Rothman, Alan L

    2011-05-01

    The pathophysiology of dengue virus infection remains poorly understood, although secondary infection is strongly associated with more severe disease. In the present study, we performed a nested, case-control study comparing the responses of pre-illness peripheral blood mononuclear cells between children who would subsequently develop either subclinical or symptomatic secondary infection 6-11 months after the baseline blood samples were obtained and frozen. We analyzed intracellular cytokine production by CD4(+) and CD8(+) cells in response to stimulation with dengue antigen. We found higher frequencies of dengue virus-specific TNFα, IFNγ-, and IL-2-producing T cells among schoolchildren who subsequently developed subclinical infection, compared with those who developed symptomatic secondary dengue virus infection. Although other studies have correlated immune responses during secondary infection with severity of disease, to our knowledge this is the first study to demonstrate a pre-infection dengue-specific immune response that correlates specifically with a subclinical secondary infection.

  3. [Presence of autocomplementary RNA with viral specificity in cells infected with herpes virus].

    Science.gov (United States)

    Béchet, J M; Montagnier, L; Latarjet, R

    1975-01-13

    RNA from cells infected with Herpes simplex virus contain a higher percentage of double-stranded RNA than non-infected cells. This percentage increases three-fold upon self-annealing. The complementary RNA sequences were shown to be virus-specific by the following criteria: (1) high melting temperature than double-stranded RNA from non infected cells; (2) higher density in caesium sulphate; (3) specific hybridization with viral DNA.

  4. Regulation of Noxa-mediated apoptosis in Helicobacter pylori–infected gastric epithelial cells

    OpenAIRE

    2014-01-01

    Helicobacter pylori induces the antiapoptotic protein myeloid cell leukemia 1 (Mcl1) in human gastric epithelial cells (GECs). Apoptosis of oncogenic protein Mcl1-expressing cells is mainly regulated by Noxa-mediated degradation of Mcl1. We wanted to elucidate the status of Noxa in H. pylori–infected GECs. For this, various GECs such as AGS, MKN45, and KATO III were either infected with H. pylori or left uninfected. The effect of infection was examined by immunoblotting, immunoprecipitation, ...

  5. Integrated Metabolomics, Transcriptomics and Proteomics Identifies Metabolic Pathways Affected by Anaplasma phagocytophilum Infection in Tick Cells.

    Science.gov (United States)

    Villar, Margarita; Ayllón, Nieves; Alberdi, Pilar; Moreno, Andrés; Moreno, María; Tobes, Raquel; Mateos-Hernández, Lourdes; Weisheit, Sabine; Bell-Sakyi, Lesley; de la Fuente, José

    2015-12-01

    Anaplasma phagocytophilum is an emerging zoonotic pathogen that causes human granulocytic anaplasmosis. These intracellular bacteria establish infection by affecting cell function in both the vertebrate host and the tick vector, Ixodes scapularis. Previous studies have characterized the tick transcriptome and proteome in response to A. phagocytophilum infection. However, in the postgenomic era, the integration of omics datasets through a systems biology approach allows network-based analyses to describe the complexity and functionality of biological systems such as host-pathogen interactions and the discovery of new targets for prevention and control of infectious diseases. This study reports the first systems biology integration of metabolomics, transcriptomics, and proteomics data to characterize essential metabolic pathways involved in the tick response to A. phagocytophilum infection. The ISE6 tick cells used in this study constitute a model for hemocytes involved in pathogen infection and immune response. The results showed that infection affected protein processing in endoplasmic reticulum and glucose metabolic pathways in tick cells. These results supported tick-Anaplasma co-evolution by providing new evidence of how tick cells limit pathogen infection, while the pathogen benefits from the tick cell response to establish infection. Additionally, ticks benefit from A. phagocytophilum infection by increasing survival while pathogens guarantee transmission. The results suggested that A. phagocytophilum induces protein misfolding to limit the tick cell response and facilitate infection but requires protein degradation to prevent ER stress and cell apoptosis to survive in infected cells. Additionally, A. phagocytophilum may benefit from the tick cell's ability to limit bacterial infection through PEPCK inhibition leading to decreased glucose metabolism, which also results in the inhibition of cell apoptosis that increases infection of tick cells. These results

  6. Demonstration of NK cell-mediated lysis of varicella-zoster virus (VZV)-infected cells: characterization of the effector cells

    Energy Technology Data Exchange (ETDEWEB)

    Tilden, A.B.; Cauda, R.; Grossi, C.E.; Balch, C.M.; Lakeman, A.D.; Whitley, R.J.

    1986-06-01

    Infection with varicella-zoster virus (VZV) rendered RAJI cells more susceptible to lysis by non-adherent blood lymphocytes. At an effector to target ratio of 80:1 the mean percentage of /sup 51/Cr release of VZV-infected RAJI cells was 41 +/- 12%, whereas that of uninfected RAJI cells was 15 +/- 6%. The increased susceptibility to lysis was associated with increased effector to target conjugate formation in immunofluorescence binding assays. The effector cells cytotoxic for VZV-infected RAJI cells were predominantly Leu-11a/sup +/ Leu-4/sup -/ granular lymphocytes as demonstrated by fluorescence-activated cell sorting. The effector cell active against VZV-infected RAJI cells appeared similar to those active against herpes simplex virus (HSV)-infected cells, because in cold target competition experiments the lysis of /sup 51/Cr-labeled VZV-infected RAJI cells was efficiently inhibited by either unlabeled VZV-infected RAJI cells (mean 71% inhibition, 2:1 ratio unlabeled to labeled target) or HSV-infected RAJI cells (mean 69% inhibition) but not by uninfected RAJI cells (mean 10% inhibition). In contrast, competition experiments revealed donor heterogeneity in the overlap between effector cells for VZV- or HSV-infected RAJI vs K-562 cells.

  7. Detection of Plasmodium falciparum-infected red blood cells by optical stretching

    Science.gov (United States)

    Mauritz, Jakob M. A.; Tiffert, Teresa; Seear, Rachel; Lautenschläger, Franziska; Esposito, Alessandro; Lew, Virgilio L.; Guck, Jochen; Kaminski, Clemens F.

    2010-05-01

    We present the application of a microfluidic optical cell stretcher to measure the elasticity of malaria-infected red blood cells. The measurements confirm an increase in host cell rigidity during the maturation of the parasite Plasmodium falciparum. The device combines the selectivity and sensitivity of single-cell elasticity measurements with a throughput that is higher than conventional single-cell techniques. The method has potential to detect early stages of infection with excellent sensitivity and high speed.

  8. Selective culling of high avidity antigen-specific CD4+ T cells after virulent Salmonella infection.

    Science.gov (United States)

    Ertelt, James M; Johanns, Tanner M; Mysz, Margaret A; Nanton, Minelva R; Rowe, Jared H; Aguilera, Marijo N; Way, Sing Sing

    2011-12-01

    Typhoid fever is a persistent infection caused by host-adapted Salmonella strains adept at circumventing immune-mediated host defences. Given the importance of T cells in protection, the culling of activated CD4+ T cells after primary infection has been proposed as a potential immune evasion strategy used by this pathogen. We demonstrate that the purging of activated antigen-specific CD4+ T cells after virulent Salmonella infection requires SPI-2 encoded virulence determinants, and is not restricted only to cells with specificity to Salmonella-expressed antigens, but extends to CD4+ T cells primed to expand by co-infection with recombinant Listeria monocytogenes. Unexpectedly, however, the loss of activated CD4+ T cells during Salmonella infection demonstrated using a monoclonal population of adoptively transferred CD4+ T cells was not reproduced among the endogenous repertoire of antigen-specific CD4+ T cells identified with MHC class II tetramer. Analysis of T-cell receptor variable segment usage revealed the selective loss and reciprocal enrichment of defined CD4+ T-cell subsets after Salmonella co-infection that is associated with the purging of antigen-specific cells with the highest intensity of tetramer staining. Hence, virulent Salmonella triggers the selective culling of high avidity activated CD4+ T-cell subsets, which re-shapes the repertoire of antigen-specific T cells that persist later after infection.

  9. Infection Profiles of Selected Aquabirnavirus Isolates in CHSE Cells.

    Directory of Open Access Journals (Sweden)

    Amr A A Gamil

    Full Text Available The wide host range and antigenic diversity of aquabirnaviruses are reflected by the presence of a collection of isolates with different sero- and genotypic properties that have previously been classified as such. Differences in cytopathogenic mechanisms and host responses induced by these isolates have not been previously examined. In the present study, we investigated infection profiles induced by genetically and serologically closely related as well as distant isolates in-vitro. CHSE-214 cells were infected with either E1S (serotype A3, genogroup 3, VR-299 (serotype A1, genogroup 1, highly virulent Sp (TA or avirulent Sp (PT (serotype A2, genogroup 5. The experiments were performed at temperatures most optimum for each of the isolates namely 15°C for VR-299, TA and PT strains and 20°C for E1S. Differences in virus loads and ability to induce cytopathic effect, inhibition of protein synthesis, apoptosis, and induction of IFNa, Mx1, PKR or TNFα gene expression at different times post infection were examined. The results showed on one hand, E1S with the highest ability to replicate, induce apoptosis and IFNa gene expression while VR-299 inhibited protein synthesis and induced Mx1 and PKR gene expression the most. The two Sp isolates induced the highest TNFα gene expression but differed in their ability to replicate, inhibit protein synthesis, and induce gene expression, with TA being more superior. Collectively, these findings point towards the adaptation by different virus isolates to suit environments and hosts that they patronize. Furthermore, the results also suggest that genetic identity is not prerequisite to functional similarities thus results of one aquabirnavirus isolate cannot necessarily be extrapolated to another.

  10. Regulation of T cell migration during viral infection: role of adhesion molecules and chemokines

    DEFF Research Database (Denmark)

    Thomsen, Allan Randrup; Nansen, Anneline; Madsen, Andreas Nygaard

    2003-01-01

    T cell mediated immunity and in particular CD8+ T cells are pivotal for the control of most viral infections. T cells exclusively exert their antiviral effect through close cellular interaction with relevant virus-infected target cells in vivo. It is therefore imperative that efficient mechanisms...... exist, which will rapidly direct newly generated effector T cells to sites of viral replication. In the present report we have reviewed our present knowledge concerning the molecular interactions, which are important in targeting of effector CD8+ T cells to sites of viral infection....

  11. Asymptotic behaviors of a cell-to-cell HIV-1 infection model perturbed by white noise

    Science.gov (United States)

    Liu, Qun

    2017-02-01

    In this paper, we analyze a mathematical model of cell-to-cell HIV-1 infection to CD4+ T cells perturbed by stochastic perturbations. First of all, we investigate that there exists a unique global positive solution of the system for any positive initial value. Then by using Lyapunov analysis methods, we study the asymptotic property of this solution. Moreover, we discuss whether there is a stationary distribution for this system and if it owns the ergodic property. Numerical simulations are presented to illustrate the theoretical results.

  12. [Promoting effect of Chlamydia pneumoniae infection on human laryngeal carcinoma HEp-2 cell adhesion and migration].

    Science.gov (United States)

    Zhang, Li-Jun; Hong, Li; Chen, Ning; Shen, Bing-Ling; Deng, Yan-Qiu; Quan, Wei; Wang, Bei-Bei; Zhang, Li-Jun

    2011-01-01

    To explore the effect of Chlamydia pneumoniae (C.pn) infection on human laryngeal carcinoma cell line HEp-2 cell adhesion and migration, to further clarify the role and mechanism of C.pn infection in tumor metastasis. HEp-2 cells were infected with C.pn after the culture and propagation of C.pn. The cytopathic effect was observed by microscopy. Morphological characteristics of C.pn inclusions in HEp-2 cells were examined by fluorescence microscopy and acridine orange staining. The ultrastructural changes of C.pn inclusions in the HEp-2 cells were examined by transmission electron microscopy (TEM). Cell adhesion assay was performed to investigate the effect of C.pn infection on the adhesion of HEp-2 cells to collagen I. Wound-healing assay and transwell assay were performed to explore the effect of C.pn infection on HEp-2 cell migration. At 72 h post-infection, C.pn infected-HEp-2 cells were swollen and partially desquamated. Numerous vacuoles (inclusions) were observed and C.pn inclusions occupied almost the whole cytoplasm of the HEp-2 cells. Grape-like C.pn inclusions were observed in the HEp-2 cells stained with acridine orange under a fluorescence microscope at 72 h after infection. Under TEM, there were more mature pear-shaped elementary bodies, but less larger and round reticulate bodies in the HEp-2 cells infected with C.pn for 72 h. In the cell adhesion assay, the A value in C.pn infection group was 0.669 ± 0.011, significantly higher than that in the control group (0.558 ± 0.005) at 2 h after infection (P HEp-2 cells in the wound-healing assay was significantly longer than that of control cells at 24 h after infection (P HEp-2 cells infected with C.pn for 12 h migrated more than the control cells in the transwell assay (23.40 ± 2.41 vs 10.40 ± 1.67) (P HEp-2 cell adhesion to collagen I and migration of HEp-2 cells, indicating that C.pn infection may play an important role in promoting the metastasis of laryngeal cancer.

  13. Vaccinia virus infection attenuates innate immune responses and antigen presentation by epidermal dendritic cells.

    Science.gov (United States)

    Deng, Liang; Dai, Peihong; Ding, Wanhong; Granstein, Richard D; Shuman, Stewart

    2006-10-01

    Langerhans cells (LCs) are antigen-presenting cells in the skin that play sentinel roles in host immune defense by secreting proinflammatory molecules and activating T cells. Here we studied the interaction of vaccinia virus with XS52 cells, a murine epidermis-derived dendritic cell line that serves as a surrogate model for LCs. We found that vaccinia virus productively infects XS52 cells, yet this infection displays an atypical response to anti-poxvirus agents. Whereas adenosine N1-oxide blocked virus production and viral protein synthesis during a synchronous infection, cytosine arabinoside had no effect at concentrations sufficient to prevent virus replication in BSC40 monkey kidney cells. Vaccinia virus infection of XS52 cells not only failed to elicit the production of various cytokines, including tumor necrosis factor alpha (TNF-alpha), interleukin-1beta (IL-1beta), IL-6, IL-10, IL-12 p40, alpha interferon (IFN-alpha), and IFN-gamma, it actively inhibited the production of proinflammatory cytokines TNF-alpha and IL-6 by XS52 cells in response to exogenous lipopolysaccharide (LPS) or poly(I:C). Infection with a vaccinia virus mutant lacking the E3L gene resulted in TNF-alpha secretion in the absence of applied stimuli. Infection of XS52 cells or BSC40 cells with the DeltaE3L virus, but not wild-type vaccinia virus, triggered proteolytic decay of IkappaBalpha. These results suggest a novel role for the E3L protein as an antagonist of the NF-kappaB signaling pathway. DeltaE3L-infected XS52 cells secreted higher levels of TNF-alpha and IL-6 in response to LPS and poly(I:C) than did cells infected with the wild-type virus. XS52 cells were productively infected by a vaccinia virus mutant lacking the K1L gene. DeltaK1L-infected cells secreted higher levels of TNF-alpha and IL-6 in response to LPS than wild-type virus-infected cells. Vaccinia virus infection of primary LCs harvested from mouse epidermis was nonpermissive, although a viral reporter protein was

  14. Spectroscopic investigation of herpes simplex viruses infected cells and their response to antiviral therapy

    Science.gov (United States)

    Erukhimovitch, Vitaly; Talyshinsky, Marina; Souprun, Yelena; Huleihel, Mahmoud

    2006-07-01

    In the present study, we used microscopic Fourier transform infrared spectroscopy (FTIR) to evaluate the antiviral activity of known antiviral agents against herpes viruses. The antiviral activity of Caffeic acid phenethyl ester (CAPE) (which is an active compound of propolis) against herpes simplex type 1 and 2 was examined in cell culture. The advantage of microscopic FTIR spectroscopy over conventional FTIR spectroscopy is that it facilitates inspection of restricted regions of cell culture or tissue. Our results showed significant spectral differences at early stages of infection between infected and non-infected cells, and between infected cells treated with the used antiviral agent and those not treated. In infected cells, there was a considerable increase in phosphate levels. Our results show that treatment with used antiviral agent considerably abolish the spectral changes induced by the viral infection. In addition, it is possible to track by FTIR microscopy method the deferential effect of various doses of the drug.

  15. Host Cell Factors as Antiviral Targets in Arenavirus Infection

    Directory of Open Access Journals (Sweden)

    Elsa B. Damonte

    2012-09-01

    Full Text Available Among the members of the Arenaviridae family, Lassa virus and Junin virus generate periodic annual outbreaks of severe human hemorrhagic fever (HF in endemic areas of West Africa and Argentina, respectively. Given the human health threat that arenaviruses represent and the lack of a specific and safe chemotherapy, the search for effective antiviral compounds is a continuous demanding effort. Since diverse host cell pathways and enzymes are used by RNA viruses to fulfill their replicative cycle, the targeting of a host process has turned an attractive antiviral approach in the last years for many unrelated virus types. This strategy has the additional benefit to reduce the serious challenge for therapy of RNA viruses to escape from drug effects through selection of resistant variants triggered by their high mutation rate. This article focuses on novel strategies to identify inhibitors for arenavirus therapy, analyzing the potential for antiviral developments of diverse host factors essential for virus infection.

  16. Host cell factors as antiviral targets in arenavirus infection.

    Science.gov (United States)

    Linero, Florencia N; Sepúlveda, Claudia S; Giovannoni, Federico; Castilla, Viviana; García, Cybele C; Scolaro, Luis A; Damonte, Elsa B

    2012-09-01

    Among the members of the Arenaviridae family, Lassa virus and Junin virus generate periodic annual outbreaks of severe human hemorrhagic fever (HF) in endemic areas of West Africa and Argentina, respectively. Given the human health threat that arenaviruses represent and the lack of a specific and safe chemotherapy, the search for effective antiviral compounds is a continuous demanding effort. Since diverse host cell pathways and enzymes are used by RNA viruses to fulfill their replicative cycle, the targeting of a host process has turned an attractive antiviral approach in the last years for many unrelated virus types. This strategy has the additional benefit to reduce the serious challenge for therapy of RNA viruses to escape from drug effects through selection of resistant variants triggered by their high mutation rate. This article focuses on novel strategies to identify inhibitors for arenavirus therapy, analyzing the potential for antiviral developments of diverse host factors essential for virus infection.

  17. Plasmacytoid Dendritic Cells and the Control of Herpesvirus Infections

    Directory of Open Access Journals (Sweden)

    Thomas Baranek

    2009-10-01

    Full Text Available Type-I interferons (IFN-I are cytokines essential for vertebrate antiviral defense, including against herpesviruses. IFN-I have potent direct antiviral activities and also mediate a multiplicity of immunoregulatory functions, which can either promote or dampen antiviral adaptive immune responses. Plasmacytoid dendritic cells (pDCs are the professional producers of IFN-I in response to many viruses, including all of the herpesviruses tested. There is strong evidence that pDCs could play a major role in the initial orchestration of both innate and adaptive antiviral immune responses. Depending on their activation pattern, pDC responses may be either protective or detrimental to the host. Here, we summarize and discuss current knowledge regarding pDC implication in the physiopathology of mouse and human herpesvirus infections, and we discuss how pDC functions could be manipulated in immunotherapeutic settings to promote health over disease.

  18. The association of killer cell immunoglobulin like receptor gene polylmorphism with cytomegalovirus infection after hematopoietic stem cell transplantation

    Institute of Scientific and Technical Information of China (English)

    吴小津

    2013-01-01

    Objective To explore the influence of the killer cell immunoglobulin like receptor(KIR)gene polymorphism on cytomegalovirus(CMV)infection and pathogenesis after hematopoietic stem cell transplantation(HSCT)

  19. Estradiol reduces susceptibility of CD4+ T cells and macrophages to HIV-infection.

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    Marta Rodriguez-Garcia

    Full Text Available The magnitude of the HIV epidemic in women requires urgent efforts to find effective preventive methods. Even though sex hormones have been described to influence HIV infection in epidemiological studies and regulate different immune responses that may affect HIV infection, the direct role that female sex hormones play in altering the susceptibility of target cells to HIV-infection is largely unknown. Here we evaluated the direct effect of 17-β-estradiol (E2 and ethinyl estradiol (EE in HIV-infection of CD4(+ T-cells and macrophages. Purified CD4(+ T-cells and monocyte-derived macrophages were generated in vitro from peripheral blood and infected with R5 and X4 viruses. Treatment of CD4(+ T-cells and macrophages with E2 prior to viral challenge reduced their susceptibility to HIV infection in a dose-dependent manner. Addition of E2 2 h after viral challenge however did not result in reduced infection. In contrast, EE reduced infection in macrophages to a lesser extent than E2 and had no effect on CD4(+ T-cell infection. Reduction of HIV-infection induced by E2 in CD4(+ T-cells was not due to CCR5 down-regulation, but was an entry-mediated mechanism since infection with VSV-G pseudotyped HIV was not modified by E2. In macrophages, despite the lack of an effect of E2 on CCR5 expression, E2-treatment reduced viral entry 2 h after challenge and increased MIP-1β secretion. These results demonstrate the direct effect of E2 on susceptibility of HIV-target cells to infection and indicate that inhibition of target cell infection involves cell-entry related mechanisms.

  20. Hepatitis C virus infection causes cell cycle arrest at the level of initiation of mitosis.

    Science.gov (United States)

    Kannan, Rathi P; Hensley, Lucinda L; Evers, Lauren E; Lemon, Stanley M; McGivern, David R

    2011-08-01

    Chronic infection with the hepatitis C virus (HCV) is associated with increased risk for hepatocellular carcinoma (HCC). Chronic immune-mediated inflammation is likely to be an important factor in the development of HCV-associated HCC, but direct effects of HCV infection on the host cell cycle may also play a role. Although overexpression studies have revealed multiple interactions between HCV-encoded proteins and host cell cycle regulators and tumor suppressor proteins, the relevance of these observations to HCV-associated liver disease is not clear. We determined the net effect of these interactions on regulation of the cell cycle in the context of virus infection. Flow cytometry of HCV-infected carboxyfluorescein succinimidyl ester-labeled hepatoma cells indicated a slowdown in proliferation that correlated with abundance of viral antigen. A decrease in the proportions of infected cells in G(1) and S phases with an accumulation of cells in G(2)/M phase was observed, compared to mock-infected controls. Dramatic decreases in markers of mitosis, such as phospho-histone H3, in infected cells suggested a block to mitotic entry. In common with findings described in the published literature, we observed caspase 3 activation, suggesting that cell cycle arrest is associated with apoptosis. Differences were observed in patterns of cell cycle disturbance and levels of apoptosis with different strains of HCV. However, the data suggest that cell cycle arrest at the interface of G(2) and mitosis is a common feature of HCV infection.

  1. Preliminary study on Herpes simplex virus type 1 infection of human oral epithelial cell in vitro

    Institute of Scientific and Technical Information of China (English)

    Jie Zhao; Weibin Sun; Juan Wang

    2008-01-01

    Objective: To explore the functions and mechanisms of herpes simplex virus type 1(HSV-1) while infecting human oral epithelial cells in vitro(being similar to the infection in vivo). Methods:An abundance of HSV-1 strains amplified in Vero cells were used to infect human oral epithelial cells. The culture supernatant was collected to infect Veto cells again. Morphology of HSV-1 was identified by inverted microscope and transmission electron microscope. Nucleic acid of the virus was detected by PCR. Results:The infected human oral epithelial cells didn't display an obvious cytopathic effect(CPE) under inverted microscope(while Veto cells which were infected by the culture supematant showed typical(CPE). The virus particles were not observed in the cytoplasm nor in nucleus of human oral epithelial cells, however under transmission electron microscope in the cytoplasm of Vero cells, the nucleic acid of HSV-1 could be detected in infected human oral epithelial cells, by PCR. Conclusion:HSV-1 can successfully infect human oral epithelial cells. This model may provide a useful approach for studying the pathogenesis of herpes virus-associated periodontal disease.

  2. Differences in Cell Activation by Chlamydophila pneumoniae and Chlamydia trachomatis Infection in Human Endothelial Cells

    Science.gov (United States)

    Krüll, M.; Kramp, J.; Petrov, T.; Klucken, A. C.; Hocke, A. C.; Walter, C.; Schmeck, B.; Seybold, J.; Maass, M.; Ludwig, S.; Kuipers, Jens G.; Suttorp, N.; Hippenstiel, S.

    2004-01-01

    Seroepidemiological studies and demonstration of viable bacteria in atherosclerotic plaques have linked Chlamydophila pneumoniae infection to the development of chronic vascular lesions and coronary heart disease. In this study, we characterized C. pneumoniae-mediated effects on human endothelial cells and demonstrated enhanced phosphorylation and activation of the endothelial mitogen-activated protein kinase (MAPK) family members extracellular receptor kinase (ERK1/2), p38-MAPK, and c-Jun-NH2 kinase (JNK). Subsequent interleukin-8 (IL-8) expression was dependent on p38-MAPK and ERK1/2 activation as demonstrated by preincubation of endothelial cells with specific inhibitors for the p38-MAPK (SB202190) or ERK (U0126) pathway. Inhibition of either MAPK had almost no effect on intercellular cell adhesion molecule 1 (ICAM-1) expression. While Chlamydia trachomatis was also able to infect endothelial cells, it did not induce the expression of endothelial IL-8 or ICAM-1. These effects were specific for a direct stimulation with viable C. pneumoniae and independent of paracrine release of endothelial cell-derived mediators like platelet-activating factor, NO, prostaglandins, or leukotrienes. Thus, C. pneumoniae triggers an early signal transduction cascade in target cells that could lead to endothelial cell activation, inflammation, and thrombosis, which in turn may result in or promote atherosclerosis. PMID:15501794

  3. HIV-1/HSV-2 co-infected adults in early HIV-1 infection have elevated CD4+ T cell counts.

    Directory of Open Access Journals (Sweden)

    Jason D Barbour

    Full Text Available INTRODUCTION: HIV-1 is often acquired in the presence of pre-existing co-infections, such as Herpes Simplex Virus 2 (HSV-2. We examined the impact of HSV-2 status at the time of HIV-1 acquisition for its impact on subsequent clinical course, and total CD4+ T cell phenotypes. METHODS: We assessed the relationship of HSV-1/HSV-2 co-infection status on CD4+ T cell counts and HIV-1 RNA levels over time prior in a cohort of 186 treatment naïve adults identified during early HIV-1 infection. We assessed the activation and differentiation state of total CD4+ T cells at study entry by HSV-2 status. RESULTS: Of 186 recently HIV-1 infected persons, 101 (54% were sero-positive for HSV-2. There was no difference in initial CD8+ T cell count, or differences between the groups for age, gender, or race based on HSV-2 status. Persons with HIV-1/HSV-2 co-infection sustained higher CD4+ T cell counts over time (+69 cells/ul greater (SD = 33.7, p = 0.04 than those with HIV-1 infection alone (Figure 1, after adjustment for HIV-1 RNA levels (-57 cells per 1 log(10 higher HIV-1 RNA, p<0.0001. We did not observe a relationship between HSV-2 infection status with plasma HIV-1 RNA levels over time. HSV-2 acquisition after HIV-1 acquisition had no impact on CD4+ count or viral load. We did not detect differences in CD4+ T cell activation or differentiation state by HSV-2+ status. DISCUSSION: We observed no effect of HSV-2 status on viral load. However, we did observe that treatment naïve, recently HIV-1 infected adults co-infected with HSV-2+ at the time of HIV-1 acquisition had higher CD4+ T cell counts over time. If verified in other cohorts, this result poses a striking paradox, and its public health implications are not immediately clear.

  4. Parasitic infection improves survival from septic peritonitis by enhancing mast cell responses to bacteria in mice.

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    Rachel E Sutherland

    Full Text Available Mammals are serially infected with a variety of microorganisms, including bacteria and parasites. Each infection reprograms the immune system's responses to re-exposure and potentially alters responses to first-time infection by different microorganisms. To examine whether infection with a metazoan parasite modulates host responses to subsequent bacterial infection, mice were infected with the hookworm-like intestinal nematode Nippostrongylus brasiliensis, followed in 2-4 weeks by peritoneal injection of the pathogenic bacterium Klebsiella pneumoniae. Survival from Klebsiella peritonitis two weeks after parasite infection was better in Nippostrongylus-infected animals than in unparasitized mice, with Nippostrongylus-infected mice having fewer peritoneal bacteria, more neutrophils, and higher levels of protective interleukin 6. The improved survival of Nippostrongylus-infected mice depends on IL-4 because the survival benefit is lost in mice lacking IL-4. Because mast cells protect mice from Klebsiella peritonitis, we examined responses in mast cell-deficient Kit(W-sh/Kit(W-sh mice, in which parasitosis failed to improve survival from Klebsiella peritonitis. However, adoptive transfer of cultured mast cells to Kit(W-sh/Kit(W-sh mice restored survival benefits of parasitosis. These results show that recent infection with Nippostrongylus brasiliensis protects mice from Klebsiella peritonitis by modulating mast cell contributions to host defense, and suggest more generally that parasitosis can yield survival advantages to a bacterially infected host.

  5. Effect of Salmonella infection on cecal tonsil regulatory T cell properties in chickens

    Science.gov (United States)

    Two experiments were conducted to study Regulatory T cell (Treg) properties post-Salmonella infection in broiler birds. Four-day-old broiler chicks were orally infected with 5x106 CFU/ml Salmonella enteritidis or sterile PBS (control). Samples were collected at 4, 7, 10, and 14 d post-infection. ...

  6. Adrenaline-induced mobilization of T cells in HIV-infected patients

    DEFF Research Database (Denmark)

    Søndergaard, S R; Cozzi-Lepri, A; Ullum, H

    2000-01-01

    The present study aimed to investigate lymphocyte mobilization from peripheral cell reservoirs in HIV-infected patients. Nine HIV-infected patients on stable highly active anti-retroviral therapy (HAART), eight treatment-naive HIV-infected patients and eight HIV- controls received a 1-h adrenalin...

  7. Pandemic Influenza A (H1N1) Virus Infection Increases Apoptosis and HIV-1 Replication in HIV-1 Infected Jurkat Cells.

    Science.gov (United States)

    Wang, Xue; Tan, Jiying; Biswas, Santanu; Zhao, Jiangqin; Devadas, Krishnakumar; Ye, Zhiping; Hewlett, Indira

    2016-02-02

    Influenza virus infection has a significant impact on public health, since it is a major cause of morbidity and mortality. It is not well-known whether influenza virus infection affects cell death and human immunodeficiency virus (HIV)-1 replication in HIV-1-infected patients. Using a lymphoma cell line, Jurkat, we examined the in vitro effects of pandemic influenza A (H1N1) virus (pH1N1) infection on cell death and HIV-1 RNA production in infected cells. We found that pH1N1 infection increased apoptotic cell death through Fas and Bax-mediated pathways in HIV-1-infected Jurkat cells. Infection with pH1N1 virus could promote HIV-1 RNA production by activating host transcription factors including nuclear factor kappa-light-chain-enhancer of activated B cells (NF-ĸB), nuclear factor of activated T-cells (NFAT) and activator protein 1 (AP-1) through mitogen-activated protein kinases (MAPK) pathways and T-cell antigen receptor (TCR)-related pathways. The replication of HIV-1 latent infection could be reactivated by pH1N1 infection through TCR and apoptotic pathways. These data indicate that HIV-1 replication can be activated by pH1N1 virus in HIV-1-infected cells resulting in induction of cell death through apoptotic pathways.

  8. Impact of HCMV infection on NK cell development and function after HSCT

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    Mariella eDella Chiesa

    2013-12-01

    Full Text Available Natural Killer (NK cell function is regulated by an array of inhibitory and activating surface receptors that during NK cell differentiation, at variance with T and B cells, do not require genetic rearrangement. Importantly, NK cells are the first lymphocyte population recovering after hematopoietic stem cell transplantation (HSCT. Thus, their role in early immunity after HSCT is considered crucial, as they can importantly contribute to protect the host from tumor recurrence and viral infections before T-cell immunity is fully recovered.In order to acquire effector functions and regulatory receptors, NK cell precursors undergo a maturation process that can be analysed during immune reconstitution after HSCT. In this context, the occurrence of human cytomegalovirus (HCMV infection/reactivation was shown to accelerate NK cell maturation by promoting the differentiation of high frequencies of NK cells characterized by a KIR+NKG2A− and NKG2C+ mature phenotype. Thus, it appears that the development of NK cells and the distribution of NK cell receptors can be deeply influenced by HCMV infection. Moreover, in HCMV-infected subjects the emergence of so called memory-like or long-lived NK cells has been documented. These cells could play an important role in protecting from infections and maybe from relapse in patients transplanted for leukemia.All the aspects regarding the influence of HCMV infection on NK cell development will be discussed.

  9. DC-SIGN Facilitates Fusion of Dendritic Cells with Human T-Cell Leukemia Virus Type 1-Infected Cells

    Science.gov (United States)

    Ceccaldi, Pierre-Emmanuel; Delebecque, Frédéric; Prevost, Marie-Christine; Moris, Arnaud; Abastado, Jean-Pierre; Gessain, Antoine; Schwartz, Olivier; Ozden, Simona

    2006-01-01

    Interactions between the oncogenic retrovirus human T-cell leukemia virus type 1 (HTLV-1) and dendritic cells (DCs) are poorly characterized. We show here that monocyte-derived DCs form syncytia and are infected upon coculture with HTLV-1-infected lymphocytes. We examined the role of DC-specific ICAM-3-grabbing nonintegrin (DC-SIGN), a C-type lectin expressed in DCs, in HTLV-1-induced syncytium formation. DC-SIGN is known to bind with high affinity to various viral envelope glycoproteins, including human immunodeficiency virus (HIV) and hepatitis C virus, as well as to the cellular receptors ICAM-2 and ICAM-3. After cocultivating DCs and HTLV-1-infected cells, we found that anti-DC-SIGN monoclonal antibodies (MAbs) were able to decrease the number and size of HTLV-1-induced syncytia. Moreover, expression of the lectin in epithelial-cell lines dramatically enhanced the ability to fuse with HTLV-1-positive cells. Interestingly, in contrast to the envelope (Env) glycoproteins of HIV and other viruses, that of HTLV-1 does not bind directly to DC-SIGN. The facilitating role of the lectin in HTLV-1 syncytium formation is mediated by its interaction with ICAM-2 and ICAM-3, as demonstrated by use of MAbs directed against these adhesion molecules. Altogether, our results indicate that DC-SIGN facilitates HTLV-1 infection and fusion of DCs through an ICAM-dependent mechanism. PMID:16641270

  10. Impaired Phenotype and Function of T Follicular Helper Cells in HIV-1-Infected Children Receiving ART.

    Science.gov (United States)

    Bekele, Yonas; Amu, Sylvie; Bobosha, Kidist; Lantto, Rebecka; Nilsson, Anna; Endale, Birtukan; Gebre, Meseret; Aseffa, Abraham; Rethi, Bence; Howe, Rawleigh; Chiodi, Francesca

    2015-07-01

    T follicular helper (Tfh) cells are important components in development of specific humoral immune responses; whether the number and biology of Tfh cells is impaired in HIV-1-infected children is not yet studied.The frequency, phenotype, and function of Tfh cells and B cells were determined in blood of HIV-1-infected children receiving antiretroviral therapy (ART) and age-matched controls. Flow cytometry was used to characterize the frequency of Tfh cells and B cell subsets. Cytokine expression was measured after in vitro activation of Tfh cells.A reduced frequency of memory Tfh cells (P < 0.001) was identified in HIV-1-infected children and, on these cells, a reduced expression of programmed death-1 (PD-1) and inducible T cell costimulator (ICOS) (P < 0.001 and P < 0.01). Upon activation, the capacity of Tfh cells to express IL-4, an important cytokine for B cell function, was impaired in HIV-1-infected children.B cell subpopulations in HIV-1-infected children displayed significant differences from the control group: the frequency of resting memory (RM) B cells was reduced (P < 0.01) whereas the frequency of exhausted memory B cells increased (P < 0.001). Interestingly, the decline of RM cells correlated with the reduction of memory Tfh cells (P = 0.02).Our study shows that function and phenotype of Tfh cells, pivotal cells for establishment of adaptive B cell responses, are impaired during HIV-1 infection in children. A consistent reduction of memory Tfh cells is associated with declined frequencies of RM B cells, creating a novel link between dysfunctional features of these cell types, major players in establishment of humoral immunity.

  11. ExoU-induced procoagulant activity in Pseudomonas aeruginosa-infected airway cells.

    Science.gov (United States)

    Plotkowski, M C; Feliciano, L F P; Machado, G B S; Cunha, L G; Freitas, C; Saliba, A M; de Assis, M C

    2008-12-01

    The present study addressed the question whether ExoU, a Pseudomonas aeruginosa toxin with phospholipase A2 (PLA2) activity, may induce airway epithelial cells to overexpress tissue factor (TF) and exhibit a procoagulant phenotype. Cells from the human bronchial epithelial BEAS-2B line were infected with an ExoU-producing P. aeruginosa strain, pre-treated or not with the cytosolic PLA2 inhibitor methylarachidonyl fluorophosphate (MAFP), or with two ExoU-deficient mutants. Control noninfected and infected cells were assessed for the expression of: 1) TF mRNA by RT-PCR; 2) cell-associated TF by enzyme immunoassay and flow cytometry; 3) procoagulant activity by a colorimetric assay; and 4) microparticle-associated TF by flow cytometry. An enzyme immunoassay was also used to assess cell-associated TF in lung extracts from mice infected intratracheally with ExoU-producing and -deficient bacteria. Cells infected with the wild-type bacteria had higher levels of TF mRNA, cell-associated TF expression, procoagulant activity and released microparticle-associated TF than cells infected with the mutants. Bacterial treatment with MAFP significantly reduced the expression of TF by infected cells. Lung samples from mice infected with the wild-type bacteria exhibited higher levels of cell-associated TF and procoagulant activity. The present results demonstrate that ExoU may contribute to the pathogenesis of lung injury by inducing a tissue factor-dependent procoagulant activity in airway epithelial cells.

  12. Pathology of porcine peripheral white blood cells during infection with African swine fever virus

    Directory of Open Access Journals (Sweden)

    Karalyan Zaven

    2012-02-01

    Full Text Available Abstract Background African swine fever virus (ASFV is the causative agent of African swine fever (ASF that is the significant disease of domestic pigs. Several studies showed that ASFV can influence on porcine blood cells in vitro. Thus, we asked ourselves whether ASFV infection results in changes in porcine blood cells in vivo. A series of experiments were performed in order to investigate the effects of ASFV infection on porcine peripheral white blood cells. Nine pigs were inoculated by intramuscular injection with 104 50% hemadsorbing doses of virus (genotype II distributed in Armenia and Georgia. The total number of fifteen cell types was calculated during experimental infection. Results Although band-to-segmented neutrophils ratio became much higher (3.5 in infected pigs than in control group (0.3, marked neutropenia and lymphopenia were detected from 2 to 3 days post-infection. In addition to band neutrophils, the high number of other immature white blood cells, such as metamyelocytes, was observed during the course of infection. From the beginning of infection, atypical lymphocytes, with altered nuclear shape, arose and became 15% of total cells in the final phase of infection. Image scanning cytometry revealed hyperdiploid DNA content in atypical lymphocytes only from 5 days post-infection, indicating that DNA synthesis in pathological lymphocytes occurred in the later stages of infection. Conclusion From this study, it can be concluded that ASFV infection leads to serious changes in composition of white blood cells. Particularly, acute ASFV infection in vivo is accompanied with the emergence of immature cells and atypical lymphocytes in the host blood. The mechanisms underlying atypical cell formation remain to be elucidated.

  13. Tracking murine gammaherpesvirus 68 infection of germinal center B cells in vivo.

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    Christopher M Collins

    Full Text Available Infection of mice with murine gammaherpesvirus 68 (MHV68 provides a tractable small animal model to study various aspects of persistent gammaherpesvirus infection. We have previously utilized a transgenic MHV68 that expresses enhanced yellow fluorescent protein (EYFP to identify infected cells. While this recombinant MHV68 has been useful for identifying infected cell populations by flow cytometry, it has been suboptimal for identification of infected cells in tissue sections due to the high solubility of EYFP. Efficient detection of EYFP expressed from the MHV68 genome in tissue sections requires fixation of whole organs prior to sectioning, which frequently leads to over-fixation of some cellular antigens precluding their detection. To circumvent this issue, we describe the generation and characterization of a transgenic MHV68 harboring a fusion gene composed of the EYFP coding sequence fused to the histone H2B open reading frame. Because the H2bYFP fusion protein is tightly bound in nucleosomes in the nucleus it does not freely diffuse out of unfixed tissue sections, and thus eliminates the need for tissue fixation. We have used the MHV68-H2bYFP recombinant virus to assess the location and distribution of virus infected B cells in germinal centers during the peak of MHV68 latency in vivo. These analyses show that the physical location of distinct populations of infected germinal center B cells correlates well with their surface phenotype. Furthermore, analysis of the distribution of virus infection within germinal center B cell populations revealed that ca. 70% of MHV68 infected GC B cells are rapidly dividing centroblasts, while ca. 20% have a clear centrocyte phenotype. Finally, we have shown that marking of infected cells with MHV68-H2bYFP is extended long after the onset of latency - which should facilitate studies to track MHV68 latently infected cells at late times post-infection.

  14. Infectious salmon anaemia virus infection of Atlantic salmon gill epithelial cells

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    Weli Simon

    2013-01-01

    Full Text Available Abstract Infectious salmon anaemia virus (ISAV, a member of the Orthomyxoviridae family, infects and causes disease in farmed Atlantic salmon (Salmo salar L.. Previous studies have shown Atlantic salmon endothelial cells to be the primary targets of ISAV infection. However, it is not known if cells other than endothelial cells play a role in ISAV tropism. To further assess cell tropism, we examined ISAV infection of Atlantic salmon gill epithelial cells in vivo and in vitro. We demonstrated the susceptibility of epithelial cells to ISAV infection. On comparison of primary gill epithelial cell cultures with ISAV permissive fish cell cultures, we found the virus yield in primary gill epithelial cells to be comparable with that of salmon head kidney (SHK-1 cells, but lower than TO or Atlantic salmon kidney (ASK-II cells. Light and transmission electron microscopy (TEM revealed that the primary gill cells possessed characteristics consistent with epithelial cells. Virus histochemistry showed that gill epithelial cells expressed 4-O-acetylated sialic acid which is recognized as the ISAV receptor. To the best of our knowledge, this is the first demonstration of ISAV infection in Atlantic salmon primary gill epithelial cells. This study thus broadens our understanding of cell tropism and transmission of ISAV in Atlantic salmon.

  15. Cytomegalovirus (CMV) Infection: A Guide for Patients and Families After Stem Cell Transplant

    Science.gov (United States)

    ... Infection: A Guide for Patients and Families after Stem Cell Transplant What is cytomegalovirus (CMV)? Cytomegalovirus (CMV), a ... weakened by medicines that you must take after stem cell transplant and by the transplant itself. Your body ...

  16. Gamma interferon augments Fc gamma receptor-mediated dengue virus infection of human monocytic cells.

    OpenAIRE

    Kontny, U.; Kurane, I; Ennis, F A

    1988-01-01

    It has been reported that anti-dengue antibodies at subneutralizing concentrations augment dengue virus infection of monocytic cells. This is due to the increased uptake of dengue virus in the form of virus-antibody complexes by cells via Fc gamma receptors. We analyzed the effects of recombinant human gamma interferon (rIFN-gamma) on dengue virus infection of human monocytic cells. U937 cells, a human monocytic cell line, were infected with dengue virus in the form of virus-antibody complexe...

  17. Natural Killer Cell Function and Dysfunction in Hepatitis C Virus Infection

    Directory of Open Access Journals (Sweden)

    Kayla A. Holder

    2014-01-01

    Full Text Available Viruses must continually adapt against dynamic innate and adaptive responses of the host immune system to establish chronic infection. Only a small minority (~20% of those exposed to hepatitis C virus (HCV spontaneously clear infection, leaving approximately 200 million people worldwide chronically infected with HCV. A number of recent research studies suggest that establishment and maintenance of chronic HCV infection involve natural killer (NK cell dysfunction. This relationship is illustrated in vitro by disruption of typical NK cell responses including both cell-mediated cytotoxicity and cytokine production. Expression of a number of activating NK cell receptors in vivo is also affected in chronic HCV infection. Thus, direct in vivo and in vitro evidence of compromised NK function in chronic HCV infection in conjunction with significant epidemiological associations between the outcome of HCV infection and certain combinations of NK cell regulatory receptor and class I human histocompatibility linked antigen (HLA genotypes indicate that NK cells are important in the immune response against HCV infection. In this review, we highlight evidence suggesting that selective impairment of NK cell activity is related to establishment of chronic HCV infection.

  18. Natural Killer Cell Function and Dysfunction in Hepatitis C Virus Infection

    Science.gov (United States)

    Holder, Kayla A.; Russell, Rodney S.; Grant, Michael D.

    2014-01-01

    Viruses must continually adapt against dynamic innate and adaptive responses of the host immune system to establish chronic infection. Only a small minority (~20%) of those exposed to hepatitis C virus (HCV) spontaneously clear infection, leaving approximately 200 million people worldwide chronically infected with HCV. A number of recent research studies suggest that establishment and maintenance of chronic HCV infection involve natural killer (NK) cell dysfunction. This relationship is illustrated in vitro by disruption of typical NK cell responses including both cell-mediated cytotoxicity and cytokine production. Expression of a number of activating NK cell receptors in vivo is also affected in chronic HCV infection. Thus, direct in vivo and in vitro evidence of compromised NK function in chronic HCV infection in conjunction with significant epidemiological associations between the outcome of HCV infection and certain combinations of NK cell regulatory receptor and class I human histocompatibility linked antigen (HLA) genotypes indicate that NK cells are important in the immune response against HCV infection. In this review, we highlight evidence suggesting that selective impairment of NK cell activity is related to establishment of chronic HCV infection. PMID:25057504

  19. Gammaherpesvirus-driven plasma cell differentiation regulates virus reactivation from latently infected B lymphocytes.

    Science.gov (United States)

    Liang, Xiaozhen; Collins, Christopher M; Mendel, Justin B; Iwakoshi, Neal N; Speck, Samuel H

    2009-11-01

    Gammaherpesviruses chronically infect their host and are tightly associated with the development of lymphoproliferative diseases and lymphomas, as well as several other types of cancer. Mechanisms involved in maintaining chronic gammaherpesvirus infections are poorly understood and, in particular, little is known about the mechanisms involved in controlling gammaherpesvirus reactivation from latently infected B cells in vivo. Recent evidence has linked plasma cell differentiation with reactivation of the human gammaherpesviruses EBV and KSHV through induction of the immediate-early viral transcriptional activators by the plasma cell-specific transcription factor XBP-1s. We now extend those findings to document a role for a gammaherpesvirus gene product in regulating plasma cell differentiation and thus virus reactivation. We have previously shown that the murine gammaherpesvirus 68 (MHV68) gene product M2 is dispensable for virus replication in permissive cells, but plays a critical role in virus reactivation from latently infected B cells. Here we show that in mice infected with wild type MHV68, virus infected plasma cells (ca. 8% of virus infected splenocytes at the peak of viral latency) account for the majority of reactivation observed upon explant of splenocytes. In contrast, there is an absence of virus infected plasma cells at the peak of latency in mice infected with a M2 null MHV68. Furthermore, we show that the M2 protein can drive plasma cell differentiation in a B lymphoma cell line in the absence of any other MHV68 gene products. Thus, the role of M2 in MHV68 reactivation can be attributed to its ability to manipulate plasma cell differentiation, providing a novel viral strategy to regulate gammaherpesvirus reactivation from latently infected B cells. We postulate that M2 represents a new class of herpesvirus gene products (reactivation conditioners) that do not directly participate in virus replication, but rather facilitate virus reactivation by

  20. Gammaherpesvirus-driven plasma cell differentiation regulates virus reactivation from latently infected B lymphocytes.

    Directory of Open Access Journals (Sweden)

    Xiaozhen Liang

    2009-11-01

    Full Text Available Gammaherpesviruses chronically infect their host and are tightly associated with the development of lymphoproliferative diseases and lymphomas, as well as several other types of cancer. Mechanisms involved in maintaining chronic gammaherpesvirus infections are poorly understood and, in particular, little is known about the mechanisms involved in controlling gammaherpesvirus reactivation from latently infected B cells in vivo. Recent evidence has linked plasma cell differentiation with reactivation of the human gammaherpesviruses EBV and KSHV through induction of the immediate-early viral transcriptional activators by the plasma cell-specific transcription factor XBP-1s. We now extend those findings to document a role for a gammaherpesvirus gene product in regulating plasma cell differentiation and thus virus reactivation. We have previously shown that the murine gammaherpesvirus 68 (MHV68 gene product M2 is dispensable for virus replication in permissive cells, but plays a critical role in virus reactivation from latently infected B cells. Here we show that in mice infected with wild type MHV68, virus infected plasma cells (ca. 8% of virus infected splenocytes at the peak of viral latency account for the majority of reactivation observed upon explant of splenocytes. In contrast, there is an absence of virus infected plasma cells at the peak of latency in mice infected with a M2 null MHV68. Furthermore, we show that the M2 protein can drive plasma cell differentiation in a B lymphoma cell line in the absence of any other MHV68 gene products. Thus, the role of M2 in MHV68 reactivation can be attributed to its ability to manipulate plasma cell differentiation, providing a novel viral strategy to regulate gammaherpesvirus reactivation from latently infected B cells. We postulate that M2 represents a new class of herpesvirus gene products (reactivation conditioners that do not directly participate in virus replication, but rather facilitate virus

  1. Identification of XMRV infection-associated microRNAs in four cell types in culture.

    Directory of Open Access Journals (Sweden)

    Ketha V K Mohan

    Full Text Available INTRODUCTION: XMRV is a gammaretrovirus that was thought to be associated with prostate cancer (PC and chronic fatigue syndrome (CFS in humans until recently. The virus is culturable in various cells of human origin like the lymphocytes, NK cells, neuronal cells, and prostate cell lines. MicroRNAs (miRNA, which regulate gene expression, were so far not identified in cells infected with XMRV in culture. METHODS: Two prostate cell lines (LNCaP and DU145 and two primary cells, Peripheral Blood Lymphocytes [PBL] and Monocyte-derived Macrophages [MDM] were infected with XMRV. Total mRNA was extracted from mock- and virus-infected cells at 6, 24 and 48 hours post infection and evaluated for microRNA profile in a microarray. RESULTS: MicroRNA expression profiles of XMRV-infected continuous prostate cancer cell lines differ from that of virus-infected primary cells (PBL and MDMs. miR-193a-3p and miRPlus-E1245 observed to be specific to XMRV infection in all 4 cell types. While miR-193a-3p levels were down regulated miRPlus-E1245 on the other hand exhibited varied expression profile between the 4 cell types. DISCUSSION: The present study clearly demonstrates that cellular microRNAs are expressed during XMRV infection of human cells and this is the first report demonstrating the regulation of miR193a-3p and miRPlus-E1245 during XMRV infection in four different human cell types.

  2. Global dynamics of cell mediated immunity in viral infection models with distributed delays

    CERN Document Server

    Nakata, Yukihiko

    2010-01-01

    In this paper, we investigate global dynamics for a system of delay differential equations which describes a virus-immune interaction in \\textit{vivo}. The model has two distributed time delays describing time needed for infection of cell and virus replication. Our model admits three possible equilibria, an uninfected equilibrium and infected equilibrium with or without immune response depending on the basic reproduction number for viral infection $R_{0}$ and for CTL response $R_{1}$ such that $R_{1}1$. The immune activation has a positive role in the reduction of the infection cells and the increasing of the uninfected cells if $R_{1}>1$.

  3. Effect of anti-carbohydrate antibodies on HIV infection in a monocytic cell line (U937)

    DEFF Research Database (Denmark)

    Hansen, J E; Nielsen, C; Clausen, H;

    1991-01-01

    . This study therefore investigated the neutralization of HIV in a monocytic cell line (U937) using mAbs against these carbohydrate gp120-epitopes. While antibodies against one of the epitopes (AI) neutralized infection of U937 cells despite binding to the Fc-receptor, one mAb against the sialosyl-Tn epitope...... enhanced infection. This enhancement was independent of complement and could be blocked by mAb Leu3a against the CD4-receptor. The study indicated that enhancement of infection in monocytic cells can occur by the same anti-carbohydrate antibodies that neutralize infection in lymphocytes, and that antibody...

  4. HIV integration sites in latently infected cell lines: evidence of ongoing replication.

    Science.gov (United States)

    Symons, Jori; Chopra, Abha; Malatinkova, Eva; De Spiegelaere, Ward; Leary, Shay; Cooper, Don; Abana, Chike O; Rhodes, Ajantha; Rezaei, Simin D; Vandekerckhove, Linos; Mallal, Simon; Lewin, Sharon R; Cameron, Paul U

    2017-01-13

    Assessing the location and frequency of HIV integration sites in latently infected cells can potentially inform our understanding of how HIV persists during combination antiretroviral therapy. We developed a novel high throughput sequencing method to evaluate HIV integration sites in latently infected cell lines to determine whether there was virus replication or clonal expansion in these cell lines observed as multiple integration events at the same position. We modified a previously reported method using random DNA shearing and PCR to allow for high throughput robotic processing to identify the site and frequency of HIV integration in latently infected cell lines. Latently infected cell lines infected with intact virus demonstrated multiple distinct HIV integration sites (28 different sites in U1, 110 in ACH-2 and 117 in J1.1 per 150,000 cells). In contrast, cell lines infected with replication-incompetent viruses (J-Lat cells) demonstrated single integration sites. Following in vitro passaging of the ACH-2 cell line, we observed a significant increase in the frequency of unique HIV integration sites and there were multiple mutations and large deletions in the proviral DNA. When the ACH-2 cell line was cultured with the integrase inhibitor raltegravir, there was a significant decrease in the number of unique HIV integration sites and a transient increase in the frequency of 2-LTR circles consistent with virus replication in these cells. Cell lines latently infected with intact HIV demonstrated multiple unique HIV integration sites indicating that these cell lines are not clonal and in the ACH-2 cell line there was evidence of low level virus replication. These findings have implications for the use of latently infected cell lines as models of HIV latency and for the use of these cells as standards.

  5. Comprehensive longitudinal analysis of hepatitis C virus (HCV)-specific T cell responses during acute HCV infection in the presence of existing HIV-1 infection

    NARCIS (Netherlands)

    C.H.S.B. van den Berg; T.A. Ruys; N.M. Nanlohy; S.E. Geerlings; J.T. van der Meer; J.W. Mulder; J.A. Lange; D. van Baarle

    2009-01-01

    The aim of this study was to study the development of HCV-specific T cell immunity during acute HCV infection in the presence of an existing HIV-1 infection in four HIV-1 infected men having sex with men. A comprehensive analysis of HCV-specific T cell responses was performed at two time points duri

  6. The presence of protective cytotoxic T lymphocytes does not correlate with shorter lifespans of productively infected cells in HIV-1 infection

    NARCIS (Netherlands)

    Spits, Hilde B; Mudrikova, Tania; Schellens, Ingrid M M; Wensing, Annemarie M J; Prins, Jan M; Feuth, Thijs; Spierings, Erik; Nijhuis, Monique; van Baarle, Debbie; Borghans, José A M

    2016-01-01

    OBJECTIVES AND DESIGN: CD8+ cytotoxic T lymphocytes (CTL) are important in the control of HIV infection. Although CTL are thought to reduce the lifespan of productively infected cells, CD8+ T-cell depletion in simian immunodeficiency virus-infected rhesus-macaques showed no effect on the lifespan of

  7. Alterations in the nuclear proteome of HIV-1 infected T-cells

    Energy Technology Data Exchange (ETDEWEB)

    DeBoer, Jason [Department of Medical Microbiology and Immunology, Creighton University, 2500 California Plaza, Omaha, NE 68178 (United States); Jagadish, Teena; Haverland, Nicole A. [Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198 (United States); Madson, Christian J. [Department of Medical Microbiology and Immunology, Creighton University, 2500 California Plaza, Omaha, NE 68178 (United States); Ciborowski, Pawel [Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198 (United States); The Nebraska Center for Virology, University of Nebraska, Lincoln 68583 (United States); Belshan, Michael, E-mail: michaelbelshan@creighton.edu [Department of Medical Microbiology and Immunology, Creighton University, 2500 California Plaza, Omaha, NE 68178 (United States); The Nebraska Center for Virology, University of Nebraska, Lincoln 68583 (United States)

    2014-11-15

    Virus infection of a cell involves the appropriation of host factors and the innate defensive response of the cell. The identification of proteins critical for virus replication may lead to the development of novel, cell-based inhibitors. In this study we mapped the changes in T-cell nuclei during human immunodeficiency virus type 1 (HIV-1) at 20 hpi. Using a stringent data threshold, a total of 13 and 38 unique proteins were identified in infected and uninfected cells, respectively, across all biological replicates. An additional 15 proteins were found to be differentially regulated between infected and control nuclei. STRING analysis identified four clusters of protein–protein interactions in the data set related to nuclear architecture, RNA regulation, cell division, and cell homeostasis. Immunoblot analysis confirmed the differential expression of several proteins in both C8166-45 and Jurkat E6-1 T-cells. These data provide a map of the response in host cell nuclei upon HIV-1 infection. - Highlights: • We identify changes in the expression of nuclear proteins during HIV-1 infection. • 163 nuclear proteins were found differentially regulated during HIV-1 infection. • Bioinformatic analysis identified several nuclear pathways altered by HIV infection. • Candidate factors were validated in two independent cell lines.

  8. Cell migration is another player of the minute virus of mice infection

    Energy Technology Data Exchange (ETDEWEB)

    Garcin, Pierre O.; Panté, Nelly, E-mail: pante@zoology.ubc.ca

    2014-11-15

    The parvovirus minute virus of mice, prototype strain (MVMp), preferentially infects and kills cancer cells. This intrinsic MVMp oncotropism may depend in part on the early stages of MVMp infection. To test this hypothesis, we investigated the early events of MVMp infection in mouse LA9 fibroblasts and a highly invasive mouse mammary tumor cell line derived from polyomavirus middle T antigen-mediated transformation. Using a combination of fluorescence and electron microscopy, we found that various parameters of the cell migration process affect MVMp infection. We show that, after binding to the plasma membrane, MVMp particles rapidly cluster at the leading edge of migrating cells, which exhibit higher levels of MVMp uptake than non-motile cells. Moreover, promoting cell migration on a fibronectin matrix increased MVMp infection, and induction of epithelial–mesenchymal transition allowed MVMp replication in non-permissive epithelial cells. Hence, we propose that cell migration influences the early stages of MVMp infection. - Highlights: • We document early steps of MVMp infection. • We report that a fibronectin matrix promotes MVMp infection. • We show that cellular migration plays a role in MVMp uptake. • We show that epithelial–mesenchymal transition allows MVMp replication.

  9. Identification of an LGP2-associated MDA5 agonist in picornavirus-infected cells

    NARCIS (Netherlands)

    Deddouche, Safia; Goubau, Delphine; Rehwinkel, Jan; Chakravarty, Probir; Begum, Sharmin; Maillard, Pierre V; Borg, Annabel; Matthews, Nik; Feng, Qian; van Kuppeveld, Frank J M|info:eu-repo/dai/nl/156614723; Reis e Sousa, Caetano

    2014-01-01

    The RIG-I-like receptors RIG-I, LGP2, and MDA5 initiate an antiviral response that includes production of type I interferons (IFNs). The nature of the RNAs that trigger MDA5 activation in infected cells remains unclear. Here, we purify and characterise LGP2/RNA complexes from cells infected with

  10. Medroxyprogesterone acetate increases HIV-1 infection of unstimulated peripheral blood mononuclear cells in vitro.

    Science.gov (United States)

    Sampah, Maame Efua S; Laird, Gregory M; Blankson, Joel N; Siliciano, Robert F; Coleman, Jenell S

    2015-06-19

    Several observational studies suggest that medroxyprogesterone acetate (MPA) injectable contraceptives may increase a woman's risk of sexual HIV-1 acquisition. In-vitro studies are conflicting, mainly due to differences in the type of progestin studied or activation status of the primary cells. We sought to determine whether MPA increases infection of unstimulated peripheral blood mononuclear cells (PBMCs). Freshly isolated PBMCs from normal blood donors were treated with physiologic MPA concentrations ranging from 0.003 to 5 ng/ml and infected with GFP-tagged R5-tropic or X4-tropic HIV-1 pseudoviruses by spinoculation. The infection was limited to a single cycle. Cells were stained with CD3, CD8 and CD14. Infection was quantified as the percentage of GFP cells by flow cytometry. Absolute infection was greater among unstimulated MPA-treated CD3⁺CD8⁻ T cells vs. untreated cells across MPA concentrations of 0.003-3 ng/ml using R5 (P  0.5). The CD3⁺CD8⁻ T-cell population of MPA-treated unstimulated PBMCs were more susceptible to HIV-1 infection than untreated cells. The increased infection was partly due to monocytes and was lost when PBMC were exogenously stimulated. These data provide confirmation of a biological association between MPA exposure and increased susceptibility to HIV-1 infection, particularly among women who inject drugs.

  11. T-cell dynamics in healthy and HIV-infected individuals

    NARCIS (Netherlands)

    Vrisekoop, N.

    2007-01-01

    This thesis focuses on T-cell dynamics in healthy and both treated and untreated HIV-infected individuals. Although the progressive decline in CD4+ T-cell numbers is the hallmark of HIV infection, the mechanisms behind this depletion remain controversial. Currently the most prevailing ideas include

  12. Sofosbuvir and Simeprevir Treatment of a Stem Cell Transplanted Teenager With Chronic Hepatitis C Infection.

    Science.gov (United States)

    Fischler, Björn; Priftakis, Peter; Sundin, Mikael

    2016-06-01

    There have been no previous reports on the use of interferon-free combinations in pediatric patients with chronic hepatitis C infection. An infected adolescent with severe sickle cell disease underwent stem cell transplantation and subsequent treatment with sofosbuvir and simeprevir during ongoing immunosuppression. Despite the emergence of peripheral edema as a side effect, treatment was continued with sustained antiviral response.

  13. Membrane prteins of herpes simplex infected cells. Immunological and biochemical studies

    NARCIS (Netherlands)

    Welling-Wester, Sijtske

    1981-01-01

    As a consequence of infection with herpes simplex virus (HSV), cells exhibit a number of alterations. One of these is expressed as a change in the polypeptide composition of the surface of the infected cells. In this study several methods used for the isolation of these polypeptides expressed on the

  14. KI and WU polyomaviruses and CD4+ cell counts in HIV-1-infected patients, Italy.

    Science.gov (United States)

    Babakir-Mina, Muhammed; Ciccozzi, Massimo; Farchi, Francesca; Bergallo, Massimiliano; Cavallo, Rossana; Adorno, Gaspare; Perno, Carlo Federico; Ciotti, Marco

    2010-09-01

    To investigate an association between KI and WU polyomavirus (KIPyV and WUPyV) infections and CD4+ cell counts, we tested HIV-1-positive patients and blood donors. No association was found between cell counts and virus infections in HIV-1-positive patients. Frequency of KIPyV infection was similar for both groups. WUPyV was more frequent in HIV-1-positive patients.

  15. Divergent CD4+ T memory stem cell dynamics in pathogenic and nonpathogenic simian immunodeficiency virus infections.

    Science.gov (United States)

    Cartwright, Emily K; McGary, Colleen S; Cervasi, Barbara; Micci, Luca; Lawson, Benton; Elliott, Sarah T C; Collman, Ronald G; Bosinger, Steven E; Paiardini, Mirko; Vanderford, Thomas H; Chahroudi, Ann; Silvestri, Guido

    2014-05-15

    Recent studies have identified a subset of memory T cells with stem cell-like properties (T(SCM)) that include increased longevity and proliferative potential. In this study, we examined the dynamics of CD4(+) T(SCM) during pathogenic SIV infection of rhesus macaques (RM) and nonpathogenic SIV infection of sooty mangabeys (SM). Whereas SIV-infected RM show selective numeric preservation of CD4(+) T(SCM), SIV infection induced a complex perturbation of these cells defined by depletion of CD4(+)CCR5(+) T(SCM), increased rates of CD4(+) T(SCM) proliferation, and high levels of direct virus infection. The increased rates of CD4(+) T(SCM) proliferation in SIV-infected RM correlated inversely with the levels of central memory CD4(+) T cells. In contrast, nonpathogenic SIV infection of SM evidenced preservation of both CD4(+) T(SCM) and CD4(+) central memory T cells, with normal levels of CD4(+) T(SCM) proliferation, and lack of selective depletion of CD4(+)CCR5(+) T(SCM). Importantly, SIV DNA was below the detectable limit in CD4(+) T(SCM) from 8 of 10 SIV-infected SM. We propose that increased proliferation and infection of CD4(+) T(SCM) may contribute to the pathogenesis of SIV infection in RM.

  16. Lysis of endogenously infected CD4+ T cell blasts by rIL-2 activated autologous natural killer cells from HIV-infected viremic individuals.

    Directory of Open Access Journals (Sweden)

    Manuela Fogli

    2008-07-01

    Full Text Available Understanding the cellular mechanisms that ensure an appropriate innate immune response against viral pathogens is an important challenge of biomedical research. In vitro studies have shown that natural killer (NK cells purified from healthy donors can kill heterologous cell lines or autologous CD4+ T cell blasts exogenously infected with several strains of HIV-1. However, it is not known whether the deleterious effects of high HIV-1 viremia interferes with the NK cell-mediated cytolysis of autologous, endogenously HIV-1-infected CD4+ T cells. Here, we stimulate primary CD4+ T cells, purified ex vivo from HIV-1-infected viremic patients, with PHA and rIL2 (with or without rIL-7. This experimental procedure allows for the significant expansion and isolation of endogenously infected CD4+ T cell blasts detected by intracellular staining of p24 HIV-1 core antigen. We show that, subsequent to the selective down-modulation of MHC class-I (MHC-I molecules, HIV-1-infected p24(pos blasts become partially susceptible to lysis by rIL-2-activated NK cells, while uninfected p24(neg blasts are spared from killing. This NK cell-mediated killing occurs mainly through the NKG2D activation pathway. However, the degree of NK cell cytolytic activity against autologous, endogenously HIV-1-infected CD4+ T cell blasts that down-modulate HLA-A and -B alleles and against heterologous MHC-I(neg cell lines is particularly low. This phenomenon is associated with the defective surface expression and engagement of natural cytotoxicity receptors (NCRs and with the high frequency of the anergic CD56(neg/CD16(pos subsets of highly dysfunctional NK cells from HIV-1-infected viremic patients. Collectively, our data demonstrate that the chronic viral replication of HIV-1 in infected individuals results in several phenotypic and functional aberrancies that interfere with the NK cell-mediated killing of autologous p24(pos blasts derived from primary T cells.

  17. IL-4Rα-Associated Antigen Processing by B Cells Promotes Immunity in Nippostrongylus brasiliensis Infection

    Science.gov (United States)

    Hoving, Jennifer C.; Nieuwenhuizen, Natalie; McSorley, Henry J.; Ndlovu, Hlumani; Bobat, Saeeda; Kimberg, Matti; Kirstein, Frank; Cutler, Anthony J.; DeWals, Benjamin; Cunningham, Adam F.; Brombacher, Frank

    2013-01-01

    In this study, B cell function in protective TH2 immunity against N. brasiliensis infection was investigated. Protection against secondary infection depended on IL-4Rα and IL-13; but not IL-4. Protection did not associate with parasite specific antibody responses. Re-infection of B cell-specific IL-4Rα−/− mice resulted in increased worm burdens compared to control mice, despite their equivalent capacity to control primary infection. Impaired protection correlated with reduced lymphocyte IL-13 production and B cell MHC class II and CD86 surface expression. Adoptive transfer of in vivo N. brasiliensis primed IL-4Rα expressing B cells into naïve BALB/c mice, but not IL-4Rα or IL-13 deficient B cells, conferred protection against primary N. brasiliensis infection. This protection required MHC class II compatibility on B cells suggesting cognate interactions by B cells with CD4+ T cells were important to co-ordinate immunity. Furthermore, the rapid nature of these protective effects by B cells suggested non-BCR mediated mechanisms, such as via Toll Like Receptors, was involved, and this was supported by transfer experiments using antigen pulsed Myd88−/− B cells. These data suggest TLR dependent antigen processing by IL-4Rα-responsive B cells producing IL-13 contribute significantly to CD4+ T cell-mediated protective immunity against N. brasiliensis infection. PMID:24204255

  18. Viral infection triggers rapid differentiation of human blood monocytes into dendritic cells.

    Science.gov (United States)

    Hou, Wanqiu; Gibbs, James S; Lu, Xiuju; Brooke, Christopher B; Roy, Devika; Modlin, Robert L; Bennink, Jack R; Yewdell, Jonathan W

    2012-03-29

    Surprisingly little is known about the interaction of human blood mononuclear cells with viruses. Here, we show that monocytes are the predominant cell type infected when peripheral blood mononuclear cells are exposed to viruses ex vivo. Remarkably, infection with vesicular stomatitis virus, vaccinia virus, and a variety of influenza A viruses (including circulating swine-origin virus) induces monocytes to differentiate within 18 hours into CD16(-)CD83(+) mature dendritic cells with enhanced capacity to activate T cells. Differentiation into dendritic cells does not require cell division and occurs despite the synthesis of viral proteins, which demonstrates that monocytes counteract the capacity of these highly lytic viruses to hijack host cell biosynthetic capacity. Indeed, differentiation requires infectious virus and viral protein synthesis. These findings demonstrate that monocytes are uniquely susceptible to viral infection among blood mononuclear cells, with the likely purpose of generating cells with enhanced capacity to activate innate and acquired antiviral immunity.

  19. Influenza H5N1 virus infection of polarized human alveolar epithelial cells and lung microvascular endothelial cells

    Directory of Open Access Journals (Sweden)

    Yuen Kit M

    2009-10-01

    Full Text Available Abstract Background Highly pathogenic avian influenza (HPAI H5N1 virus is entrenched in poultry in Asia and Africa and continues to infect humans zoonotically causing acute respiratory disease syndrome and death. There is evidence that the virus may sometimes spread beyond respiratory tract to cause disseminated infection. The primary target cell for HPAI H5N1 virus in human lung is the alveolar epithelial cell. Alveolar epithelium and its adjacent lung microvascular endothelium form host barriers to the initiation of infection and dissemination of influenza H5N1 infection in humans. These are polarized cells and the polarity of influenza virus entry and egress as well as the secretion of cytokines and chemokines from the virus infected cells are likely to be central to the pathogenesis of human H5N1 disease. Aim To study influenza A (H5N1 virus replication and host innate immune responses in polarized primary human alveolar epithelial cells and lung microvascular endothelial cells and its relevance to the pathogenesis of human H5N1 disease. Methods We use an in vitro model of polarized primary human alveolar epithelial cells and lung microvascular endothelial cells grown in transwell culture inserts to compare infection with influenza A subtype H1N1 and H5N1 viruses via the apical or basolateral surfaces. Results We demonstrate that both influenza H1N1 and H5N1 viruses efficiently infect alveolar epithelial cells from both apical and basolateral surface of the epithelium but release of newly formed virus is mainly from the apical side of the epithelium. In contrast, influenza H5N1 virus, but not H1N1 virus, efficiently infected polarized microvascular endothelial cells from both apical and basolateral aspects. This provides a mechanistic explanation for how H5N1 virus may infect the lung from systemic circulation. Epidemiological evidence has implicated ingestion of virus-contaminated foods as the source of infection in some instances and our

  20. Differences between Mycobacterium-Host Cell Relationships in Latent Tuberculous Infection of Mice Ex Vivo and Mycobacterial Infection of Mouse Cells In Vitro.

    Science.gov (United States)

    Ufimtseva, Elena

    2016-01-01

    The search for factors that account for the reproduction and survival of mycobacteria, including vaccine strains, in host cells is the priority for studies on tuberculosis. A comparison of BCG-mycobacterial loads in granuloma cells obtained from bone marrow and spleens of mice with latent tuberculous infection and cells from mouse bone marrow and peritoneal macrophage cultures infected with the BCG vaccine in vitro has demonstrated that granuloma macrophages each normally contained a single BCG-Mycobacterium, while those acutely infected in vitro had increased mycobacterial loads and death rates. Mouse granuloma cells were observed to produce the IFNγ, IL-1α, GM-CSF, CD1d, CD25, CD31, СD35, and S100 proteins. None of these activation markers were found in mouse cell cultures infected in vitro or in intact macrophages. Lack of colocalization of lipoarabinomannan-labeled BCG-mycobacteria with the lysosomotropic LysoTracker dye in activated granuloma macrophages suggests that these macrophages were unable to destroy BCG-mycobacteria. However, activated mouse granuloma macrophages could control mycobacterial reproduction in cells both in vivo and in ex vivo culture. By contrast, a considerable increase in the number of BCG-mycobacteria was observed in mouse bone marrow and peritoneal macrophages after BCG infection in vitro, when no expression of the activation-related molecules was detected in these cells.

  1. Zika Virus Infection of the Human Glomerular Cells: Implications for Viral Reservoirs and Renal Pathogenesis.

    Science.gov (United States)

    Alcendor, Donald J

    2017-07-15

    Zika virus (ZIKV) infection in the human renal compartment has not been reported. Several clinical reports have describe high-level persistent viral shedding in the urine of infected patients, but the associated mechanisms have not been explored until now. The current study examined cellular components of the glomerulus of the human kidney for ZIKV infectivity. I infected primary human podocytes, renal glomerular endothelial cells (GECs), and mesangial cells with ZIKV. Viral infectivity was analyzed by means of microscopy, immunofluorescence, real-time reverse-transcription polymerase chain reaction (RT-PCR), and quantitative RT-PCR (qRT-PCR), and the proinflammatory cytokines interleukin 1β, interferon β, and RANTES (regulated on activation of normal T cells expressed and secreted) were assessed using qRT-PCR. I show that glomerular podocytes, renal GECs, and mesangial cells are permissive for ZIKV infection. ZIKV infectivity was confirmed in all 3 cell types by means of immunofluorescence staining, RT-PCR, and qRT-PCR, and qRT-PCR analysis revealed increased transcriptional induction of interleukin 1β, interferon β, and RANTES in ZIKV-infected podocytes at 72 hours, compared with renal GECs and mesangial cells. The findings of this study support the notion that the glomerulus may serve as an amplification reservoir for ZIKV in the renal compartment. The impact of ZIKV infection in the human renal compartment is unknown and will require further study.

  2. Quantitative proteome profiling of respiratory virus-infected lung epithelial cells.

    Science.gov (United States)

    van Diepen, Angela; Brand, H Kim; Sama, Iziah; Lambooy, Lambert H J; van den Heuvel, Lambert P; van der Well, Leontine; Huynen, Martijn; Osterhaus, Albert D M E; Andeweg, Arno C; Hermans, Peter W M

    2010-08-05

    Respiratory virus infections are among the primary causes of morbidity and mortality in humans. Influenza virus, respiratory syncytial virus (RSV), parainfluenza (PIV) and human metapneumovirus (hMPV) are major causes of respiratory illness in humans. Especially young children and the elderly are susceptible to infections with these viruses. In this study we aim to gain detailed insight into the molecular pathogenesis of respiratory virus infections by studying the protein expression profiles of infected lung epithelial cells. A549 cells were exposed to a set of respiratory viruses [RSV, hMPV, PIV and Measles virus (MV)] using both live and UV-inactivated virus preparations. Cells were harvested at different time points after infection and processed for proteomics analysis by 2-dimensional difference gel electrophoresis. Samples derived from infected cells were compared to mock-infected cells to identify proteins that are differentially expressed due to infection. We show that RSV, hMPV, PIV3, and MV induced similar core host responses and that mainly proteins involved in defense against ER stress and apoptosis were affected which points towards an induction of apoptosis upon infection. By 2-D DIGE analyses we have gathered information on the induction of apoptosis by respiratory viruses in A549 cells.

  3. Human borna disease virus infection impacts host proteome and histone lysine acetylation in human oligodendroglia cells

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xia [Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016 (China); Department of Neurology, The Fifth People' s Hospital of Shanghai, School of Medicine, Fudan University, Shanghai, 200240 (China); Zhao, Libo [Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016 (China); Department of Neurology, The Third People' s Hospital of Chongqing, 400014 (China); Yang, Yongtao [Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016 (China); Chongqing Key Laboratory of Neurobiology, Chongqing Medical University, Chongqing, 400016 (China); Institute of Neuroscience, Chongqing Medical University, Chongqing, 400016 (China); Bode, Liv [Bornavirus Research Group affiliated to the Free University of Berlin, Berlin (Germany); Huang, Hua [Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016 (China); Chongqing Key Laboratory of Neurobiology, Chongqing Medical University, Chongqing, 400016 (China); Institute of Neuroscience, Chongqing Medical University, Chongqing, 400016 (China); Liu, Chengyu [Chongqing Key Laboratory of Neurobiology, Chongqing Medical University, Chongqing, 400016 (China); Institute of Neuroscience, Chongqing Medical University, Chongqing, 400016 (China); Huang, Rongzhong [Department of Rehabilitative Medicine, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010 (China); Zhang, Liang [Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016 (China); Chongqing Key Laboratory of Neurobiology, Chongqing Medical University, Chongqing, 400016 (China); Institute of Neuroscience, Chongqing Medical University, Chongqing, 400016 (China); and others

    2014-09-15

    Background: Borna disease virus (BDV) replicates in the nucleus and establishes persistent infections in mammalian hosts. A human BDV strain was used to address the first time, how BDV infection impacts the proteome and histone lysine acetylation (Kac) of human oligodendroglial (OL) cells, thus allowing a better understanding of infection-driven pathophysiology in vitro. Methods: Proteome and histone lysine acetylation were profiled through stable isotope labeling for cell culture (SILAC)-based quantitative proteomics. The quantifiable proteome was annotated using bioinformatics. Histone acetylation changes were validated by biochemistry assays. Results: Post BDV infection, 4383 quantifiable differential proteins were identified and functionally annotated to metabolism pathways, immune response, DNA replication, DNA repair, and transcriptional regulation. Sixteen of the thirty identified Kac sites in core histones presented altered acetylation levels post infection. Conclusions: BDV infection using a human strain impacted the whole proteome and histone lysine acetylation in OL cells. - Highlights: • A human strain of BDV (BDV Hu-H1) was used to infect human oligodendroglial cells (OL cells). • This study is the first to reveal the host proteomic and histone Kac profiles in BDV-infected OL cells. • BDV infection affected the expression of many transcription factors and several HATs and HDACs.

  4. A Role for Human Skin Mast Cells in Dengue Virus Infection and Systemic Spread.

    Science.gov (United States)

    Troupin, Andrea; Shirley, Devon; Londono-Renteria, Berlin; Watson, Alan M; McHale, Cody; Hall, Alex; Hartstone-Rose, Adam; Klimstra, William B; Gomez, Gregorio; Colpitts, Tonya M

    2016-12-01

    Dengue virus (DENV) is a mosquito-borne flavivirus that causes serious global human disease and mortality. Skin immune cells are an important component of initial DENV infection and systemic spread. Here, we show that mast cells are a target of DENV in human skin and that DENV infection of skin mast cells induces degranulation and alters cytokine and growth factor expression profiles. Importantly, to our knowledge, we also demonstrate for the first time that DENV localizes within secretory granules in infected skin mast cells. In addition, DENV within extracellular granules was infectious in vitro and in vivo, trafficking through lymph to draining lymph nodes in mice. We demonstrate an important role for human skin mast cells in DENV infection and identify a novel mechanism for systemic spread of DENV infection from the initial peripheral mosquito injection site. Copyright © 2016 by The American Association of Immunologists, Inc.

  5. Early Loss of Splenic Tfh Cells in SIV-Infected Rhesus Macaques.

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    Félicien Moukambi

    2015-12-01

    Full Text Available Follicular T helper cells (Tfh, a subset of CD4 T lymphocytes, provide crucial help to B cells in the production of antigen-specific antibodies. Although several studies have analyzed the dynamics of Tfh cells in peripheral blood and lymph nodes (LNs during Aids, none has yet addressed the impact of SIV infection on the dynamics of Tfh cells in the spleen, the primary organ of B cell activation. We show here a significant decrease in splenic Tfh cells in SIVmac251-infected rhesus macaques (RMs during the acute phase of infection, which persists thereafter. This profound loss is associated with lack of sustained expression of the Tfh-defining transcription factors, Bcl-6 and c-Maf but with higher expression of the repressors KLF2 and Foxo1. In this context of Tfh abortive differentiation and loss, we found decreased percentages of memory B cell subsets and lower titers of SIV-specific IgG. We further demonstrate a drastic remodeling of the lymphoid architecture of the spleen and LNs, which disrupts the crucial cell-cell interactions necessary to maintain memory B cells and Tfh cells. Finally, our data demonstrated the early infection of Tfh cells. Paradoxically, the frequencies of SIV DNA were higher in splenic Tfh cells of RMs progressing more slowly suggesting sanctuaries for SIV in the spleen. Our findings provide important information regarding the impact of HIV/SIV infection on Tfh cells, and provide new clues for future vaccine strategies.

  6. Dynamic immune cell recruitment after murine pulmonary Aspergillus fumigatus infection under different immunosuppressive regimens

    Directory of Open Access Journals (Sweden)

    Natarajaswamy Kalleda

    2016-07-01

    Full Text Available Humans are continuously exposed to airborne spores of the saprophytic fungus Aspergillus fumigatus. However, in healthy individuals pulmonary host defense mechanisms efficiently eliminate the fungus. In contrast, A. fumigatus causes devastating infections in immunocompromised patients. Host immune responses against A. fumigatus lung infections in immunocompromised conditions have remained largely elusive. Given the dynamic changes in immune cell subsets within tissues upon immunosuppressive therapy, we dissected the spatiotemporal pulmonary immune response after A. fumigatus infection to reveal basic immunological events that fail to effectively control invasive fungal disease. In different immunocompromised murine models, myeloid, notably neutrophils and macrophages, but not lymphoid cells were strongly recruited to the lungs upon infection. Other myeloid cells, particularly dendritic cells and monocytes, were only recruited to lungs of corticosteroid treated mice, which developed a strong pulmonary inflammation after infection. Lymphoid cells, particularly CD4+ or CD8+ T-cells and NK cells were highly reduced upon immunosuppression and not recruited after A. fumigatus infection. Moreover, adoptive CD11b+ myeloid cell transfer rescued cyclophosphamide immunosuppressed mice from lethal A. fumigatus infection but not cortisone and cyclophosphamide immunosuppressed mice. Our findings illustrate that CD11b+ myeloid cells are critical for anti-A. fumigatus defense under cyclophosphamide immunosuppressed conditions.

  7. Antigen Exposure History Defines CD8 T Cell Dynamics and Protection during Localized Pulmonary Infections

    Science.gov (United States)

    Van Braeckel-Budimir, Natalija; Martin, Matthew D.; Hartwig, Stacey M.; Legge, Kevin L.; Badovinac, Vladimir P.; Harty, John T.

    2017-01-01

    Unlike systemic infections, little is known about the role of repeated localized infections on (re)shaping pathogen-specific memory CD8 T cell responses. Here, we used primary (1°) and secondary (2°) intranasal influenza virus infections of mice as a model to study intrinsic memory CD8 T cell properties. We show that secondary antigen exposure, relative to a single infection, generates memory CD8 T cell responses of superior magnitude in multiple tissue compartments including blood, spleen, draining lymph nodes, and lung. Unexpectedly, regardless of the significantly higher number of 2° memory CD8 T cells, similar degree of protection against pulmonary challenge was observed in both groups of mice containing 1° or 2° memory CD8 T cells. Mechanistically, using pertussis toxin-induced migration block, we showed that superior antigen-driven proliferation and ability to relocate to the site of infection allowed 1° memory CD8 T cells to accumulate in the infected lung during the first few days after challenge, compensating for the initially lower cell numbers. Taken together, the history of antigen exposures to localized pulmonary infections, through altering basic cell biology, dictates dynamic properties of protective memory CD8 T cell responses. This knowledge has important implications for a design of novel and an improvement of existing vaccines and immunization strategies. PMID:28191007

  8. Lymphocytes and macrophages are infected by Theileria equi, but T cells and B cells are not required to establish infection in vivo.

    Science.gov (United States)

    Ramsay, Joshua D; Ueti, Massaro W; Johnson, Wendell C; Scoles, Glen A; Knowles, Donald P; Mealey, Robert H

    2013-01-01

    Theileria equi has a biphasic life cycle in horses, with a period of intraleukocyte development followed by patent erythrocytic parasitemia that causes acute and sometimes fatal hemolytic disease. Unlike Theileria spp. that infect cattle (Theileria parva and Theileria annulata), the intraleukocyte stage (schizont) of Theileria equi does not cause uncontrolled host cell proliferation or other significant pathology. Nevertheless, schizont-infected leukocytes are of interest because of their potential to alter host cell function and because immune responses directed against this stage could halt infection and prevent disease. Based on cellular morphology, Theileria equi has been reported to infect lymphocytes in vivo and in vitro, but the specific phenotype of schizont-infected cells has yet to be defined. To resolve this knowledge gap in Theileria equi pathogenesis, peripheral blood mononuclear cells were infected in vitro and the phenotype of infected cells determined using flow cytometry and immunofluorescence microscopy. These experiments demonstrated that the host cell range of Theileria equi was broader than initially reported and included B lymphocytes, T lymphocytes and monocyte/macrophages. To determine if B and T lymphocytes were required to establish infection in vivo, horses affected with severe combined immunodeficiency (SCID), which lack functional B and T lymphocytes, were inoculated with Theileria equi sporozoites. SCID horses developed patent erythrocytic parasitemia, indicating that B and T lymphocytes are not necessary to complete the Theileria equi life cycle in vivo. These findings suggest that the factors mediating Theileria equi leukocyte invasion and intracytoplasmic differentiation are common to several leukocyte subsets and are less restricted than for Theileria annulata and Theileria parva. These data will greatly facilitate future investigation into the relationships between Theileria equi leukocyte tropism and pathogenesis, breed

  9. Lymphocytes and macrophages are infected by Theileria equi, but T cells and B cells are not required to establish infection in vivo.

    Directory of Open Access Journals (Sweden)

    Joshua D Ramsay

    Full Text Available Theileria equi has a biphasic life cycle in horses, with a period of intraleukocyte development followed by patent erythrocytic parasitemia that causes acute and sometimes fatal hemolytic disease. Unlike Theileria spp. that infect cattle (Theileria parva and Theileria annulata, the intraleukocyte stage (schizont of Theileria equi does not cause uncontrolled host cell proliferation or other significant pathology. Nevertheless, schizont-infected leukocytes are of interest because of their potential to alter host cell function and because immune responses directed against this stage could halt infection and prevent disease. Based on cellular morphology, Theileria equi has been reported to infect lymphocytes in vivo and in vitro, but the specific phenotype of schizont-infected cells has yet to be defined. To resolve this knowledge gap in Theileria equi pathogenesis, peripheral blood mononuclear cells were infected in vitro and the phenotype of infected cells determined using flow cytometry and immunofluorescence microscopy. These experiments demonstrated that the host cell range of Theileria equi was broader than initially reported and included B lymphocytes, T lymphocytes and monocyte/macrophages. To determine if B and T lymphocytes were required to establish infection in vivo, horses affected with severe combined immunodeficiency (SCID, which lack functional B and T lymphocytes, were inoculated with Theileria equi sporozoites. SCID horses developed patent erythrocytic parasitemia, indicating that B and T lymphocytes are not necessary to complete the Theileria equi life cycle in vivo. These findings suggest that the factors mediating Theileria equi leukocyte invasion and intracytoplasmic differentiation are common to several leukocyte subsets and are less restricted than for Theileria annulata and Theileria parva. These data will greatly facilitate future investigation into the relationships between Theileria equi leukocyte tropism and pathogenesis

  10. A bovine cell line that can be infected by natural sheep scrapie prions.

    Science.gov (United States)

    Oelschlegel, Anja M; Geissen, Markus; Lenk, Matthias; Riebe, Roland; Angermann, Marlies; Schatzl, Herman; Schaetzl, Hermann; Groschup, Martin H

    2015-01-01

    Cell culture systems represent a crucial part in basic prion research; yet, cell lines that are susceptible to prions, especially to field isolated prions that were not adapted to rodents, are very rare. The purpose of this study was to identify and characterize a cell line that was susceptible to ruminant-derived prions and to establish a stable prion infection within it. Based on species and tissue of origin as well as PrP expression rate, we pre-selected a total of 33 cell lines that were then challenged with natural and with mouse propagated BSE or scrapie inocula. Here, we report the successful infection of a non-transgenic bovine cell line, a sub-line of the bovine kidney cell line MDBK, with natural sheep scrapie prions. This cell line retained the scrapie infection for more than 200 passages. Selective cloning resulted in cell populations with increased accumulation of PrPres, although this treatment was not mandatory for retaining the infection. The infection remained stable, even under suboptimal culture conditions. The resulting infectivity of the cells was confirmed by mouse bioassay (Tgbov mice, Tgshp mice). We believe that PES cells used together with other prion permissive cell lines will prove a valuable tool for ongoing efforts to understand and defeat prions and prion diseases.

  11. A bovine cell line that can be infected by natural sheep scrapie prions.

    Directory of Open Access Journals (Sweden)

    Anja M Oelschlegel

    Full Text Available Cell culture systems represent a crucial part in basic prion research; yet, cell lines that are susceptible to prions, especially to field isolated prions that were not adapted to rodents, are very rare. The purpose of this study was to identify and characterize a cell line that was susceptible to ruminant-derived prions and to establish a stable prion infection within it. Based on species and tissue of origin as well as PrP expression rate, we pre-selected a total of 33 cell lines that were then challenged with natural and with mouse propagated BSE or scrapie inocula. Here, we report the successful infection of a non-transgenic bovine cell line, a sub-line of the bovine kidney cell line MDBK, with natural sheep scrapie prions. This cell line retained the scrapie infection for more than 200 passages. Selective cloning resulted in cell populations with increased accumulation of PrPres, although this treatment was not mandatory for retaining the infection. The infection remained stable, even under suboptimal culture conditions. The resulting infectivity of the cells was confirmed by mouse bioassay (Tgbov mice, Tgshp mice. We believe that PES cells used together with other prion permissive cell lines will prove a valuable tool for ongoing efforts to understand and defeat prions and prion diseases.

  12. Suppression of NK cell-mediated cytotoxicity against PRRSV-infected porcine alveolar macrophages in vitro.

    Science.gov (United States)

    Cao, Jun; Grauwet, Korneel; Vermeulen, Ben; Devriendt, Bert; Jiang, Ping; Favoreel, Herman; Nauwynck, Hans

    2013-06-28

    The adaptive immunity against PRRSV has already been studied in depth, but only limited data are available on the innate immune responses against this pathogen. In the present study, we analyzed the interaction between porcine natural killer (NK) cells and PRRSV-infected primary porcine alveolar macrophages (PAMs), since NK cells are one of the most important components of innate immunity and PAMs are primary target cells of PRRSV infection. NK cytotoxicity assays were performed using enriched NK cells as effector cells and virus-infected or mock-inoculated PAMs as target cells. The NK cytotoxicity against PRRSV-infected PAMs was decreased starting from 6h post inoculation (hpi) till the end of the experiment (12 hpi) and was significantly lower than that against pseudorabies virus (PrV)-infected PAMs. UV-inactivated PRRSV also suppressed NK activity, but much less than infectious PRRSV. Furthermore, co-incubation with PRRSV-infected PAMs inhibited degranulation of NK cells. Finally, using the supernatant of PRRSV-infected PAMs collected at 12 hpi showed that the suppressive effect of PRRSV on NK cytotoxicity was not mediated by soluble factors. In conclusion, PRRSV-infected PAMs showed a reduced susceptibility toward NK cytotoxicity, which may represent one of the multiple evasion strategies of PRRSV.

  13. Rapid and transient activation of gamma/delta T cells to interferon gamma production, NK cell-like killing and antigen processing during acute virus infection

    Science.gov (United States)

    Gamma/delta T cells are the majority peripheral blood T cells in young cattle. The role of gamma/delta T cells in innate responses against infection with foot-and-mouth disease virus (FMDV) was analyzed on 5 consecutive days following infection. Before infection, bovine gamma/delta T cells expressed...

  14. Sustained CD8+ T-cell responses induced after acute parvovirus B19 infection in humans

    DEFF Research Database (Denmark)

    Norbeck, Oscar; Isa, Adiba; Pöhlmann, Christoph

    2005-01-01

    Murine models have suggested that CD8+ T-cell responses peak early in acute viral infections and are not sustained, but no evidence for humans has been available. To address this, we longitudinally analyzed the CD8+ T-cell response to human parvovirus B19 in acutely infected individuals. We...... observed striking CD8+ T-cell responses, which were sustained or even increased over many months after the resolution of acute disease, indicating that CD8+ T cells may play a prominent role in the control of parvovirus B19 and other acute viral infections of humans, including potentially those generated...

  15. Theoretical models for near forward light scattering by a Plasmodium falciparum infected red blood cell

    Science.gov (United States)

    Sharma, S. K.

    2012-12-01

    A number of experimental elastic light scattering studies have been performed in the past few years with the aim of developing automated in vivo tools for differentiating a healthy red blood cell from a Plasmodium falciparum infected cell. This paper examines some theoretical aspects of the problem. An attempt has been made to simulate the scattering patterns of healthy as well as infected individual red blood cells. Two models, namely, a homogeneous sphere model and a coated sphere model have been considered. The scattering patterns predicted by these models are examined. A possible method for discriminating infected red blood cells from healthy ones has been suggested.

  16. Inhibition of experimental ascending urinary tract infection by an epithelial cell-surface receptor analogue

    Science.gov (United States)

    Edén, C. Svanborg; Freter, R.; Hagberg, L.; Hull, R.; Hull, S.; Leffler, H.; Schoolnik, G.

    1982-08-01

    It has been shown that the establishment of urinary tract infection by Escherichia coli is dependent on attachment of the bacteria to epithelial cells1-4. The attachment involves specific epithelial cell receptors, which have been characterized as glycolipids5-10. Reversible binding to cell-surface mannosides may also be important4,11-13. This suggests an approach to the treatment of infections-that of blocking bacterial attachment with cell membrane receptor analogues. Using E. coli mutants lacking one or other of the two binding specificities (glycolipid and mannose), we show here that glycolipid analogues can block in vitro adhesion and in vivo urinary tract infection.

  17. Latent KSHV Infected Endothelial Cells Are Glutamine Addicted and Require Glutaminolysis for Survival.

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    Erica L Sanchez

    2015-07-01

    Full Text Available Kaposi's Sarcoma-associated Herpesvirus (KSHV is the etiologic agent of Kaposi's Sarcoma (KS. KSHV establishes a predominantly latent infection in the main KS tumor cell type, the spindle cell, which is of endothelial cell origin. KSHV requires the induction of multiple metabolic pathways, including glycolysis and fatty acid synthesis, for the survival of latently infected endothelial cells. Here we demonstrate that latent KSHV infection leads to increased levels of intracellular glutamine and enhanced glutamine uptake. Depletion of glutamine from the culture media leads to a significant increase in apoptotic cell death in latently infected endothelial cells, but not in their mock-infected counterparts. In cancer cells, glutamine is often required for glutaminolysis to provide intermediates for the tri-carboxylic acid (TCA cycle and support for the production of biosynthetic and bioenergetic precursors. In the absence of glutamine, the TCA cycle intermediates alpha-ketoglutarate (αKG and pyruvate prevent the death of latently infected cells. Targeted drug inhibition of glutaminolysis also induces increased cell death in latently infected cells. KSHV infection of endothelial cells induces protein expression of the glutamine transporter, SLC1A5. Chemical inhibition of SLC1A5, or knockdown by siRNA, leads to similar cell death rates as glutamine deprivation and, similarly, can be rescued by αKG. KSHV also induces expression of the heterodimeric transcription factors c-Myc-Max and related heterodimer MondoA-Mlx. Knockdown of MondoA inhibits expression of both Mlx and SLC1A5 and induces a significant increase in cell death of only cells latently infected with KSHV, again, fully rescued by the supplementation of αKG. Therefore, during latent infection of endothelial cells, KSHV activates and requires the Myc/MondoA-network to upregulate the glutamine transporter, SLC1A5, leading to increased glutamine uptake for glutaminolysis. These findings

  18. EBV infection is common in gingival epithelial cells of the periodontium and worsens during chronic periodontitis.

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    Séverine Vincent-Bugnas

    Full Text Available An amplifying role for oral epithelial cells (ECs in Epstein-Barr Virus (EBV infection has been postulated to explain oral viral shedding. However, while lytic or latent EBV infections of oro/nasopharyngeal ECs are commonly detected under pathological conditions, detection of EBV-infected ECs in healthy conditions is very rare. In this study, a simple non-surgical tissue sampling procedure was used to investigate EBV infection in the periodontal epithelium that surrounds and attaches teeth to the gingiva. Surprisingly, we observed that the gingival ECs of the periodontium (pECs are commonly infected with EBV and may serve as an important oral reservoir of latently EBV-infected cells. We also found that the basal level of epithelial EBV-infection is significantly increased in chronic periodontitis, a common inflammatory disease that undermines the integrity of tooth-supporting tissues. Moreover, the level of EBV infection was found to correlate with disease severity. In inflamed tissues, EBV-infected pECs appear to be prone to apoptosis and to produce larger amounts of CCL20, a pivotal inflammatory chemokine that controls tissue infiltration by immune cells. Our discovery that the periodontal epithelium is a major site of latent EBV infection sheds a new light on EBV persistence in healthy carriers and on the role of this ubiquitous virus in periodontitis. Moreover, the identification of this easily accessible site of latent infection may encourage new approaches to investigate and monitor other EBV-associated disorders.

  19. The impact of juvenile coxsackievirus infection on cardiac progenitor cells and postnatal heart development.

    Science.gov (United States)

    Sin, Jon; Puccini, Jenna M; Huang, Chengqun; Konstandin, Mathias H; Gilbert, Paul E; Sussman, Mark A; Gottlieb, Roberta A; Feuer, Ralph

    2014-07-01

    Coxsackievirus B (CVB) is an enterovirus that most commonly causes a self-limited febrile illness in infants, but cases of severe infection can manifest in acute myocarditis. Chronic consequences of mild CVB infection are unknown, though there is an epidemiologic association between early subclinical infections and late heart failure, raising the possibility of subtle damage leading to late-onset dysfunction, or chronic ongoing injury due to inflammatory reactions during latent infection. Here we describe a mouse model of juvenile infection with a subclinical dose of coxsackievirus B3 (CVB3) which showed no evident symptoms, either immediately following infection or in adult mice. However following physiological or pharmacologically-induced cardiac stress, juvenile-infected adult mice underwent cardiac hypertrophy and dilation indicative of progression to heart failure. Evaluation of the vasculature in the hearts of adult mice subjected to cardiac stress showed a compensatory increase in CD31+ blood vessel formation, although this effect was suppressed in juvenile-infected mice. Moreover, CVB3 efficiently infected juvenile c-kit+ cells, and cardiac progenitor cell numbers were reduced in the hearts of juvenile-infected adult mice. These results suggest that the exhausted cardiac progenitor cell pool following juvenile CVB3 infection may impair the heart's ability to increase capillary density to adapt to increased load.

  20. Profiling of Host Cell Response to Successive Canine Parvovirus Infection Based on Kinetic Proteomic Change Identification

    Science.gov (United States)

    Zhao, Hang; Cheng, Yuening; Wang, Jianke; Lin, Peng; Yi, Li; Sun, Yaru; Ren, Jingqiang; Tong, Mingwei; Cao, Zhigang; Li, Jiawei; Deng, Jinliang; Cheng, Shipeng

    2016-01-01

    Canine parvovirus (CPV) reproduces by co-opting the resources of host cells, inevitably causing cytotoxic effects to the host cells. Feline kidney F81 cells are sensitive to CPV infection and show disparate growing statuses at different time points post-infection. This study analysed the response of F81 cells to CPV infection at successive infection time points by iTRAQ-based quantitative proteomics. Differentially expressed proteins (DEPs) during 60 h of infection and at selected time points post-infection were identified by an analysis of variance test and a two-tailed unpaired t test, respectively. DEPs with similar quantitative changes were clustered by hierarchical clustering and analysed by gene ontology enrichment, revealing that 12 h and 60 h post-infection were the optimal times to analyse the autonomous parvovirus replication and apoptosis processes, respectively. Using the MetacoreTM database, 29 DEPs were enriched in a network involved in p53 regulation. Besides, a significantly enriched pathway suggests that the CPV-induced cytopathic effect was probably due to the deficiency of functional CFTR caused by CPV infection. This study uncovered the systemic changes in key cellular factors involved in CPV infection and help to understand the molecular mechanisms of the anti-cancer activity of CPV and the cytopathic effects induced by CPV infection. PMID:27406444

  1. Viral Interleukin-10 Expressed by Human Cytomegalovirus during the Latent Phase of Infection Modulates Latently Infected Myeloid Cell Differentiation ▿ †

    OpenAIRE

    Avdic, Selmir; Cao, John Z.; Cheung, Allen K.L.; Abendroth, Allison; Slobedman, Barry

    2011-01-01

    The human cytomegalovirus UL111A gene is expressed during latent and productive infections, and it codes for homologs of interleukin-10 (IL-10). We examined whether viral IL-10 expressed during latency altered differentiation of latently infected myeloid progenitors. In comparison to infection with parental virus or mock infection, latent infection with a virus in which the gene encoding viral IL-10 has been deleted upregulated cytokines associated with dendritic cell (DC) formation and incre...

  2. STIM1 controls T cell-mediated immune regulation and inflammation in chronic infection.

    Science.gov (United States)

    Desvignes, Ludovic; Weidinger, Carl; Shaw, Patrick; Vaeth, Martin; Ribierre, Theo; Liu, Menghan; Fergus, Tawania; Kozhaya, Lina; McVoy, Lauren; Unutmaz, Derya; Ernst, Joel D; Feske, Stefan

    2015-06-01

    Chronic infections induce a complex immune response that controls pathogen replication, but also causes pathology due to sustained inflammation. Ca2+ influx mediates T cell function and immunity to infection, and patients with inherited mutations in the gene encoding the Ca2+ channel ORAI1 or its activator stromal interaction molecule 1 (STIM1) are immunodeficient and prone to chronic infection by various pathogens, including Mycobacterium tuberculosis (Mtb). Here, we demonstrate that STIM1 is required for T cell-mediated immune regulation during chronic Mtb infection. Compared with WT animals, mice with T cell-specific Stim1 deletion died prematurely during the chronic phase of infection and had increased bacterial burdens and severe pulmonary inflammation, with increased myeloid and lymphoid cell infiltration. Although STIM1-deficient T cells exhibited markedly reduced IFN-γ production during the early phase of Mtb infection, bacterial growth was not immediately exacerbated. During the chronic phase, however, STIM1-deficient T cells displayed enhanced IFN-γ production in response to elevated levels of IL-12 and IL-18. The lack of STIM1 in T cells was associated with impaired activation-induced cell death upon repeated TCR engagement and pulmonary lymphocytosis and hyperinflammation in Mtb-infected mice. Chronically Mtb-infected, STIM1-deficient mice had reduced levels of inducible regulatory T cells (iTregs) due to a T cell-intrinsic requirement for STIM1 in iTreg differentiation and excessive production of IFN-γ and IL-12, which suppress iTreg differentiation and maintenance. Thus, STIM1 controls multiple aspects of T cell-mediated immune regulation to limit injurious inflammation during chronic infection.

  3. Apparent reduction of ADAM10 in scrapie-infected cultured cells and in the brains of scrapie-infected rodents.

    Science.gov (United States)

    Chen, Cao; Lv, Yan; Zhang, Bao-Yun; Zhang, Jin; Shi, Qi; Wang, Jing; Tian, Chan; Gao, Chen; Xiao, Kang; Ren, Ke; Zhou, Wei; Dong, Xiao-Ping

    2014-12-01

    It has been described that A disintegrin and metalloproteinase (ADAM10) may involve in the physiopathology of prion diseases, but the direct molecular basis still remains unsolved. In this study, we confirmed that ADAM10 was able to cleave recombinant human prion protein in vitro. Using immunoprecipitation tests (IP) and immunofluorescent assays (IFA), reliable molecular interaction between the native cellular form of PrP (PrP(C)) and ADAM10 was observed not only in various cultured neuronal cell lines but also in brain homogenates of healthy hamsters and mice. Only mature ADAM10 (after removal of its prodomain) molecules showed the binding activity with the native PrP(C). Remarkably more prion protein (PrP)-ADAM10 complexes were detected in the membrane fraction of cultured cells. In the scrapie-infected SMB cell model, the endogenous ADAM10 levels, especially the mature ADAM10, were significantly decreased in the fraction of cell membrane. IP and IFA tests of prion-infected SMB-S15 cells confirmed no detectable PrP-ADAM10 complex in the cellular lysates and PrP-ADAM10 co-localization on the cell surface. Furthermore, we demonstrated that the levels of ADAM10 in the brain homogenates of scrapie agent 263K-infected hamsters and agent ME7-infected mice were also almost diminished at the terminal stage, showing time-dependent decreases during the incubation period. Our data here provide the solid molecular basis for the endoproteolysis of ADAM10 on PrP molecules and interaction between ADAM10 and PrP(C). Obvious loss of ADAM10 during prion infection in vitro and in vivo highlights that ADAM10 may play essential pathophysiological roles in prion replication and accumulation.

  4. IL-15 promotes activation and expansion of CD8+ T cells in HIV-1 infection

    Science.gov (United States)

    Younes, Souheil-Antoine; Freeman, Michael L.; Mudd, Joseph C.; Shive, Carey L.; Reynaldi, Arnold; Estes, Jacob D.; Deleage, Claire; Lucero, Carissa; Anderson, Jodi; Schacker, Timothy W.; Davenport, Miles P.; McCune, Joseph M.; Hunt, Peter W.; Lee, Sulggi A.; Debernardo, Robert L.; Jacobson, Jeffrey M.; Canaday, David H.; Sekaly, Rafick-Pierre; Sieg, Scott F.; Lederman, Michael M.

    2016-01-01

    In HIV-1–infected patients, increased numbers of circulating CD8+ T cells are linked to increased risk of morbidity and mortality. Here, we identified a bystander mechanism that promotes CD8 T cell activation and expansion in untreated HIV-1–infected patients. Compared with healthy controls, untreated HIV-1–infected patients have an increased population of proliferating, granzyme B+, CD8+ T cells in circulation. Vβ expression and deep sequencing of CDR3 revealed that in untreated HIV-1 infection, cycling memory CD8 T cells possess a broad T cell repertoire that reflects the repertoire of the resting population. This suggests that cycling is driven by bystander activation, rather than specific antigen exposure. Treatment of peripheral blood mononuclear cells with IL-15 induced a cycling, granzyme B+ phenotype in CD8+ T cells. Moreover, elevated IL-15 expression in the lymph nodes of untreated HIV-1–infected patients correlated with circulating CD8+ T cell counts and was normalized in these patients following antiretroviral therapy. Together, these results suggest that IL-15 drives bystander activation of CD8+ T cells, which predicts disease progression in untreated HIV-1–infected patients and suggests that elevated IL-15 may also drive CD8+ T cell expansion that is linked to increased morbidity and mortality in treated patients. PMID:27322062

  5. Persistent Simian Immunodeficiency Virus Infection Causes Ultimate Depletion of Follicular Th Cells in AIDS.

    Science.gov (United States)

    Xu, Huanbin; Wang, Xiaolei; Malam, Naomi; Lackner, Andrew A; Veazey, Ronald S

    2015-11-01

    CD4(+) T follicular helper (Tfh) cells are critical for the generation of humoral immune responses to pathogenic infections, providing help for B cell development, survival, and affinity maturation of Abs. Although CD4(+) Tfh cells are reported to accumulate in HIV or SIV infection, we found that germinal center Tfh cells, defined in this study as CXCR5(+)PD-1(HIGH)CD4(+) T cells, did not consistently accumulate in chronically SIV-infected rhesus macaques compared with those infected with less pathogenic simian HIV, vaccinated and SIVmac-challenged, or SIVmac-infected Mamu-A*01(+) macaques, all of which are associated with some control of virus replication and slower disease progression. Interestingly, CXCR5(+)PD-1(HIGH) Tfh cells in lymphoid tissues were eventually depleted in macaques with AIDS compared with the other cohorts. Chronic activation and proliferation of CXCR5(+)PD-1(HIGH) Tfh were increased, but PD-L2 expression was downregulated on B cells, possibly resulting in germinal center Tfh cell apoptosis. Together, these findings suggest that changes in CXCR5(+)PD-1(HIGH) Tfh cells in lymph nodes correlate with immune control during infection, and their loss or dysregulation contribute to impairment of B cell responses and progression to AIDS.

  6. Activation of lymphocytes induced by bronchial epithelial cells with prolonged RSV infection.

    Directory of Open Access Journals (Sweden)

    Ling Qin

    Full Text Available Respiratory syncytial virus (RSV preferentially infects airway epithelial cells,which might be responsible for susceptibility to asthma; however, the underlying mechanism is not clear. This study determined the activation of lymphocytes and drift of helper T (Th subsets induced by RSV-infected human bronchial epithelial cells (HBECs in vitro. HBECs had prolonged infection with RSV, and lymphocytes isolated from human peripheral blood were co-cultured with RSV-infected HBECs. Four groups were established, as follows: lymphocytes (group L; lymphocytes infected with RSV (group RL; co-culture of lymphocytes with non-infected HBECs (group HL; and co-culture of lymphocytes with infected HBECs (group HRL. After co-culture with HBECs for 24 hours, lymphocytes were collected and the following were determined in the 4 groups: cell cycle status; apoptosis rate; and concentrations of IL-4, IFN-γ, and IL-17 in the supernatants. Cell cycle analysis for lymphocytes showed a significant increase in S phase cells, a decrease in G1 phase cells, and a higher apoptosis rate in group HRL compared with the other three groups. In group HRL, the levels of IL-4, IFN-γ, and IL-17 in supernatants were also higher than the other three groups. For further study, lymphocytes were individually treated with supernatants from non-infected and RSV-infected HBECs for 24 h. We showed that supernatants from RSV-infected HBECs induced the differentiation of Th2 and Th17 subsets, and suppressed the differentiation of Treg subsets. Our results showed that HBECs with prolonged RSV infection can induce lymphocyte proliferation and apoptosis, and enhance the release of cytokines by lymphocytes. Moreover, subset drift might be caused by RSV-infected HBECs.

  7. Inhibitory effect of interferon gamma on frequency of Ehrlichia canis-infected cells in vitro.

    Science.gov (United States)

    Tajima, Tomoko; Wada, Makoto

    2013-12-15

    Ehrlichia canis is an obligate intracellular bacterium that infects the macrophage-monocyte cells of dogs, causing canine monocytic ehrlichiosis. Interferon-γ (IFN-γ), along with other cytokines, mediates the immune response to such intracellular bacterial invasions. To determine the role of IFN-γ in the immunity of dogs to E. canis infection, peripheral blood mononuclear cells (PBMC) and white blood cells (WBC) were collected from E. canis-infected dogs and added to a culture of E. canis in DH82 cells. The number of E. canis inclusion-positive cells was significantly reduced in cultures containing PBMC and WBC from E. canis-infected dogs compared to uninfected dogs. However, this resistance was inhibited by the addition of an anti-dog IFN-γ antibody. Resistance was also observed when PBMC were added to the Cell Culture Inserts, which prohibited contact of PBMC to DH82 cells, while allowed the diffusion of soluble cell products. The results of this study indicate that resistance was not dependent on cell to cell contact, but was associated with soluble cell products, such as IFN-γ. The addition of recombinant canine IFN-γ to the E. canis culture also reduced the number of infected cells. A commercial recombinant canine IFN-γ, which is sold in Japan, was also effective at reducing E. canis-infected cell number. These results indicate that IFN-γ has an inhibitory effect on the frequency of E. canis-infected cells in vitro and that contact between effector and target cells is not necessary for the resistance.

  8. Surface Antigen Profiling of Helicobacter pylori-Infected and -Uninfected Gastric Cancer Cells Using Antibody Microarray.

    Science.gov (United States)

    Sukri, Asif; Hanafiah, Alfizah; Kosai, Nik Ritza; Mohamed Taher, Mustafa; Mohamed Rose, Isa

    2016-10-01

    Comprehensive immunophenotyping cluster of differentiation (CD) antigens in gastric adenocarcinoma, specifically between Helicobacter pylori-infected and -uninfected gastric cancer patients by using DotScan(™) antibody microarray has not been conducted. Current immunophenotyping techniques include flow cytometry and immunohistochemistry are limited to the use of few antibodies for parallel examination. We used DotScan(™) antibody microarray consisting 144 CD antibodies to determine the distribution of CD antigens in gastric adenocarcinoma cells and to elucidate the effect of H. pylori infection toward CD antigen expression in gastric cancer. Mixed leukocytes population derived from gastric adenocarcinoma patients were immunophenotyped using DotScan(™) antibody microarray. AGS cells were infected with H. pylori strains and cells were captured on DotScan(™) slides. Cluster of differentiation antigens involved in perpetuating the tolerance of immune cells to tumor cells was upregulated in gastric adenocarcinoma cells compared to normal cells. CD279 which is essential in T cells apoptosis was found to be upregulated in normal cells. Remarkably, H. pylori-infected gastric cancer patients exhibited upregulated expression of CD27 that important in maintenance of T cells. Infection of cagA+ H. pylori with AGS cells increased CD antigens expression which involved in cancer stem cell while cagA- H. pylori polarized AGS cells to express immune-regulatory CD antigens. Increased CD antigens expression in AGS cells infected with cagA+ H. pylori were also detected in H. pylori-infected gastric cancer patients. This study suggests the tolerance of immune system toward tumor cells in gastric cancer and distinct mechanisms of immune responses exploited by different H. pylori strains. © 2016 John Wiley & Sons Ltd.

  9. Changes in the Proteome of Langat-Infected Ixodes scapularis ISE6 Cells: Metabolic Pathways Associated with Flavivirus Infection.

    Directory of Open Access Journals (Sweden)

    Jeffrey M Grabowski

    2016-02-01

    Full Text Available Ticks (Family Ixodidae transmit a variety of disease causing agents to humans and animals. The tick-borne flaviviruses (TBFs; family Flaviviridae are a complex of viruses, many of which cause encephalitis and hemorrhagic fever, and represent global threats to human health and biosecurity. Pathogenesis has been well studied in human and animal disease models. Equivalent analyses of tick-flavivirus interactions are limited and represent an area of study that could reveal novel approaches for TBF control.High resolution LC-MS/MS was used to analyze the proteome of Ixodes scapularis (Lyme disease tick embryonic ISE6 cells following infection with Langat virus (LGTV and identify proteins associated with viral infection and replication. Maximal LGTV infection of cells and determination of peak release of infectious virus, was observed at 36 hours post infection (hpi. Proteins were extracted from ISE6 cells treated with LGTV and non-infectious (UV inactivated LGTV at 36 hpi and analyzed by mass spectrometry. The Omics Discovery Pipeline (ODP identified thousands of MS peaks. Protein homology searches against the I. scapularis IscaW1 genome assembly identified a total of 486 proteins that were subsequently assigned to putative functional pathways using searches against the Kyoto Encyclopedia of Genes and Genomes (KEGG database. 266 proteins were differentially expressed following LGTV infection relative to non-infected (mock cells. Of these, 68 proteins exhibited increased expression and 198 proteins had decreased expression. The majority of the former were classified in the KEGG pathways: "translation", "amino acid metabolism", and "protein folding/sorting/degradation". Finally, Trichostatin A and Oligomycin A increased and decreased LGTV replication in vitro in ISE6 cells, respectively.Proteomic analyses revealed ISE6 proteins that were differentially expressed at the peak of LGTV replication. Proteins with increased expression following infection

  10. Brugia malayi infective larvae fail to activate Langerhans cells and dermal dendritic cells in human skin.

    Science.gov (United States)

    Cotton, R N; McDonald-Fleming, R; Boyd, A; Spates, K; Nutman, T B; Tolouei Semnani, R

    2015-02-01

    Filarial infection in humans is initiated when a mosquito deposits third-stage parasite larvae (L3) in the skin. Langerhans cells (LCs) and dermal dendritic cells (DDCs) are the first cells that the parasite encounters, and L3s must evade these highly effective antigen-presenting cells to establish infection. To assess LC and DDC responses to L3 in human skin, we employed three models of increasing physiologic relevance: in vitro-generated LCs, epidermal blister explants and full-thickness human skin sections. In vitro-generated LCs expressed TLR1-10 and robustly produced IL-6 and TNF-α in response to PolyI:C, but pre-exposure to L3s did not alter inflammatory cytokine production or TLR expression. L3s did not modulate expression of LC markers CDH1, CD207, or CD1a, or the regulatory products TSLP or IDO in epidermal explants or in vitro-generated LC. LC, CD14+ DDC, CD1c+ DC and CD141+ DC from human skin sections were analysed by flow cytometry. While PolyI:C potently induced CCL22 production in LC, CD1c+ DC, and CD141+ DC, and IL-10 production in LC, L3s did not modulate the numbers of or cytokine production by any skin DC subset. L3s broadly failed to activate or modulate LCs or DDCs, suggesting filarial larvae expertly evade APC detection in human skin.

  11. Porcine aminopeptidase N mediated polarized infection by porcine epidemic diarrhea virus in target cells

    Energy Technology Data Exchange (ETDEWEB)

    Cong, Yingying; Li, Xiaoxue; Bai, Yunyun [College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030 (China); Lv, Xiaonan [College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030 (China); CAS Key Lab for Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience & Technology of China, Beijing 100090 (China); Herrler, Georg [Institute for Virology, University of Veterinary Medicine, Hannover D-30559 (Germany); Enjuanes, Luis [Department of Molecular and Cell Biology, Centro Nacional de Biotecnología (CNB-CSIC), Campus Universidad Autónoma de Madrid, Cantoblanco, Madrid (Spain); Zhou, Xingdong [College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030 (China); Qu, Bo [Faculty of Life Sciences, Northeast Agricultural University, Harbin 150030 (China); Meng, Fandan [Institute for Virology, University of Veterinary Medicine, Hannover D-30559 (Germany); Cong, Chengcheng [College Animal Husbandry and Veterinary Medicine, Shenyang Agricultural University, Shenyang 110161 (China); Ren, Xiaofeng; Li, Guangxing [College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030 (China)

    2015-04-15

    Infection of polarized intestinal epithelial cells by porcine epidemic diarrhea virus (PEDV) was characterized. Indirect immunofluorescence assay, real-time PCR, and transmission electron microscopy confirmed PEDV can be successfully propagated in immortalized swine small intestine epithelial cells (IECs). Infection involved porcine aminpeptidase N (pAPN), a reported cellular receptor for PEDV, transient expression of pAPN and siRNA targeted pAPN increased and decreased the infectivity of PEDV in IECs, respectively. Subsequently, polarized entry into and release from both Vero E6 and IECs was analyzed. PEDV entry into polarized cells and pAPN grown on membrane inserts occurs via apical membrane. The progeny virus released into the medium was also quantified which demonstrated that PEDV is preferentially released from the apical membrane. Collectively, our data demonstrate that pAPN, the cellular receptor for PEDV, mediates polarized PEDV infection. These results imply the possibility that PEDV infection may proceed by lateral spread of virus in intestinal epithelial cells. - Highlights: • PEDV infection of polarized intestinal epithelial cells (IECs) was characterized. • Porcine aminpeptidase N (pAPN) facilitated PEDV infection in IECs. • PEDV entry into and release from polarized cell via its apical membrane. • PEDV infection may proceed by lateral spread of virus in IECs.

  12. West Nile virus infection does not induce PKR activation in rodent cells.

    Science.gov (United States)

    Elbahesh, H; Scherbik, S V; Brinton, M A

    2011-12-05

    dsRNA-activated protein kinase (PKR) is activated by viral dsRNAs and phosphorylates eIF2a reducing translation of host and viral mRNA. Although infection with a chimeric West Nile virus (WNV) efficiently induced PKR and eIF2a phosphorylation, infections with natural lineage 1 or 2 strains did not. Investigation of the mechanism of suppression showed that among the cellular PKR inhibitor proteins tested, only Nck, known to interact with inactive PKR, colocalized and co-immunoprecipitated with PKR in WNV-infected cells and PKR phosphorylation did not increase in infected Nck1,2-/- cells. Several WNV stem-loop RNAs efficiently activated PKR in vitro but not in infected cells. WNV infection did not interfere with intracellular PKR activation by poly(I:C) and similar virus yields were produced by control and PKR-/- cells. The results indicate that PKR phosphorylation is not actively suppressed in WNV-infected cells but that PKR is not activated by the viral dsRNA in infected cells.

  13. Legionella pneumophila infection of Drosophila S2 cells induces only minor changes in mitochondrial dynamics.

    Directory of Open Access Journals (Sweden)

    Elizabeth Wen Sun

    Full Text Available During infection of cells by Legionella pneumophila, the bacterium secretes a large number of effector proteins into the host cell cytoplasm, allowing it to alter many cellular processes and make the vacuole and the host cell into more hospitable environments for bacterial replication. One major change induced by infection is the recruitment of ER-derived vesicles to the surface of the vacuole, where they fuse with the vacuole membrane and prevent it from becoming an acidified, degradative compartment. However, the recruitment of mitochondria to the region of the vacuole has also been suggested by ultrastructural studies. In order to test this idea in a controlled and quantitative experimental system, and to lay the groundwork for a genome-wide screen for factors involved in mitochondrial recruitment, we examined the behavior of mitochondria during the early stages of Legionella pneumophila infection of Drosophila S2 cells. We found that the density of mitochondria near vacuoles formed by infection with wild type Legionella was not different from that found in dotA(- mutant-infected cells during the first 4 hours after infection. We then examined 4 parameters of mitochondrial motility in infected cells: velocity of movement, duty cycle of movement, directional persistence and net direction. In the 4 hours following infection, most of these measures were indistinguishable between wild type and dotA(-.infection. However, wild type Legionella did induce a modest shift in the velocity distribution toward faster movement compared dotA(- infection, and a small downward shift in the duty cycle distribution. In addition, wild type infection produced mitochondrial movement that was biased in the direction of the bacterial vacuole relative to dotA-, although not enough to cause a significant accumulation within 10 um of the vacuole. We conclude that in this host cell, mitochondria are not strongly recruited to the vacuole, nor is their motility

  14. Vaccination with experimental feline immunodeficiency virus vaccines, based on autologous infected cells, elicits enhancement of homologous challenge infection.

    NARCIS (Netherlands)

    J.A. Karlas (Jos); C.H.J. Siebelink (Kees); M.A. van Peer (Maartje); W. Huisman (Willem); A.M. Cuisinier; G.F. Rimmelzwaan (Guus); A.D.M.E. Osterhaus (Albert)

    1999-01-01

    textabstractCats were vaccinated with fixed autologous feline immunodeficiency virus (FIV)-infected cells in order to present viral proteins to the immune system of individual cats in an MHC-matched fashion. Upon vaccination, a humoral response against Gag was induced. Furthermore, virus-neutralizin

  15. Vaccination with experimental feline immunodeficiency virus vaccines, based on autologous infected cells, elicits enhancement of homologous challenge infection

    NARCIS (Netherlands)

    J.A. Karlas (Jos); C.H.J. Siebelink (Kees); M.A. Peer; W. Huisman (Willem); A.M. Cuisinier; G.F. Rimmelzwaan (Guus); A.D.M.E. Osterhaus (Ab)

    1999-01-01

    textabstractCats were vaccinated with fixed autologous feline immunodeficiency virus (FIV)-infected cells in order to present viral proteins to the immune system of individual cats in an MHC-matched fashion. Upon vaccination, a humoral response against Gag was induced. Furthermore,

  16. HTLV-1-infected thymic epithelial cells convey the virus to CD4(+) T lymphocytes.

    Science.gov (United States)

    Carvalho Barros, Luciana Rodrigues; Linhares-Lacerda, Leandra; Moreira-Ramos, Klaysa; Ribeiro-Alves, Marcelo; Machado Motta, Maria Cristina; Bou-Habib, Dumith Chequer; Savino, Wilson

    2017-08-14

    The human T-lymphotropic virus type-1 (HTLV-1) is the causative agent of adult T cell leukemia/lymphoma (ATL) and HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP). CD4(+)T cells are the main target of HTLV-1, but other cell types are known to be infected, including immature lymphocytes. Developing T cells undergo differentiation in the thymus, through migration and interaction with the thymic microenvironment, in particular with thymic epithelial cells (TEC) the major component of this three dimensional meshwork of non-lymphoid cells. Herein, we show that TEC express the receptors for HTLV-1 and can be infected by this virus through cell-cell contact and by cell-free virus suspensions. The expression of anti-apoptosis, chemokine and adhesion molecules genes are altered in HTLV-1-infected TEC, although gene expression of antigen presentation molecules remained unchanged. Furthermore, HTLV-1-infected TEC transmitted the virus to a CD4(+) T cell line and to CD4(+) T cells from healthy donors, during in vitro cellular co-cultures. Altogether, our data point to the possibility that the human thymic epithelial cells play a role in the establishment and progression of HTLV-1 infection, functioning as a reservoir and transmitting the virus to maturing CD4(+) T lymphocytes, which in turn will cause disease in the periphery. Copyright © 2017. Published by Elsevier GmbH.

  17. Dynamics of an HBV/HCV infection model with intracellular delay and cell proliferation

    Science.gov (United States)

    Zhang, Fengqin; Li, Jianquan; Zheng, Chongwu; Wang, Lin

    2017-01-01

    A new mathematical model of hepatitis B/C virus (HBV/HCV) infection which incorporates the proliferation of healthy hepatocyte cells and the latent period of infected hepatocyte cells is proposed and studied. The dynamics is analyzed via Pontryagin's method and a newly proposed alternative geometric stability switch criterion. Sharp conditions ensuring stability of the infection persistent equilibrium are derived by applying Pontryagin's method. Using the intracellular delay as the bifurcation parameter and applying an alternative geometric stability switch criterion, we show that the HBV/HCV infection model undergoes stability switches. Furthermore, numerical simulations illustrate that the intracellular delay can induce complex dynamics such as persistence bubbles and chaos.

  18. Inhibition of Interjacent Ribonucleic Acid (26S) Synthesis in Cells Infected by Sindbis Virus

    Science.gov (United States)

    Scheele, Christina M.; Pfefferkorn, E. R.

    1969-01-01

    The interrelationship of viral ribonucleic acid (RNA) and protein synthesis in cells infected by Sindbis virus was investigated. When cultures were treated with puromycin early in the course of infection, the synthesis of interjacent RNA (26S) was preferentially inhibited. A similar result was obtained by shifting cells infected by one temperature-sensitive mutant defective in RNA synthesis from the permissive (29 C) to the nonpermissive (41.5 C) temperature. Under both conditions, the viral RNA produced appeared to be fully active biologically. Once underway, the synthesis of viral RNA in wild-type Sindbis infections did not require concomitant protein synthesis. PMID:5817400

  19. Efficient immortalization of primary nasopharyngeal epithelial cells for EBV infection study.

    Directory of Open Access Journals (Sweden)

    Yim Ling Yip

    Full Text Available Nasopharyngeal carcinoma (NPC is common among southern Chinese including the ethnic Cantonese population living in Hong Kong. Epstein-Barr virus (EBV infection is detected in all undifferentiated type of NPC in this endemic region. Establishment of stable and latent EBV infection in premalignant nasopharyngeal epithelial cells is an early event in NPC development and may contribute to its pathogenesis. Immortalized primary nasopharyngeal epithelial cells represent an important tool for investigation of EBV infection and its tumorigenic potential in this special type of epithelial cells. However, the limited availability and small sizes of nasopharyngeal biopsies have seriously restricted the establishment of primary nasopharyngeal epithelial cells for immortalization. A reliable and effective method to immortalize primary nasopharyngeal epithelial cells will provide unrestricted materials for EBV infection studies. An earlier study has reported that Bmi-1 expression could immortalize primary nasopharyngeal epithelial cells. However, its efficiency and actions in immortalization have not been fully characterized. Our studies showed that Bmi-1 expression alone has limited ability to immortalize primary nasopharyngeal epithelial cells and additional events are often required for its immortalization action. We have identified some of the key events associated with the immortalization of primary nasopharyngeal epithelial cells. Efficient immortalization of nasopharyngeal epithelial cells could be reproducibly and efficiently achieved by the combined actions of Bmi-1 expression, activation of telomerase and silencing of p16 gene. Activation of MAPK signaling and gene expression downstream of Bmi-1 were detected in the immortalized nasopharyngeal epithelial cells and may play a role in immortalization. Furthermore, these newly immortalized nasopharyngeal epithelial cells are susceptible to EBV infection and supported a type II latent EBV infection

  20. Apoptosis and necrosis in vaccinia virus-infected HeLa G and BSC-40 cells.

    Science.gov (United States)

    Liskova, Jana; Knitlova, Jarmila; Honner, Richard; Melkova, Zora

    2011-09-01

    In most cells, vaccinia virus (VACV) infection is considered to cause a lytic cell death, an equivalent of necrosis. However, upon infection of the epithelial cell lines HeLa G and BSC-40 with VACV strain Western Reserve (WR), we have previously observed an increased activation of and activity attributable to caspases, a typical sign of apoptosis. In this paper, we have further analyzed the type of cell death in VACV-infected cells HeLa G and BSC-40. In a cell-based flow cytometric assay, we showed a specific activation of caspase-2 and 4 in HeLa G and BSC-40 cells infected with VACV, strain WR, while we did not find any effects of inhibitors of calpain and cathepsin D and E. The actual activity of the two caspases, but also of caspase-3, was then confirmed in lysates of infected HeLa G, but not in BSC-40 cells. Accordingly, poly(ADP)-ribose polymerase (PARP) cleavage was found increased only in infected HeLa G cells. Consequently, we have determined morphological features of apoptosis and/or activity of the executioner caspase-3 in infected HeLa G cells in situ, while only a background apoptosis was observed in infected BSC-40 cells. Finally, vaccination strains Dryvax and Praha were found to induce apoptosis in both HeLa G and BSC-40 cells, as characterized morphologically and by PARP cleavage. These findings may be important for understanding the differences in VACV-host interactions and post-vaccination complications in different individuals.

  1. TCR down-regulation boosts T-cell-mediated cytotoxicity and protection against poxvirus infections

    DEFF Research Database (Denmark)

    Hansen, Ann Kathrine; Regner, Matthias; Bonefeld, Charlotte Menne

    2011-01-01

    Cytotoxic T (Tc) cells play a key role in the defense against virus infections. Tc cells recognize infected cells via the T-cell receptor (TCR) and subsequently kill the target cells by one or more cytotoxic mechanisms. Induction of the cytotoxic mechanisms is finely tuned by the activation signals...... from the TCR. To determine whether TCR down-regulation affects the cytotoxicity of Tc cells, we studied TCR down-regulation-deficient CD3¿LLAA mice. We found that Tc cells from CD3¿LLAA mice have reduced cytotoxicity due to a specific deficiency in exocytosis of lytic granules. To determine whether......-regulation critically increases Tc cell cytotoxicity and protection against poxvirus infection....

  2. Rapamycin increases RSV RNA levels and survival of RSV-infected dendritic cell depending on T cell contact.

    Science.gov (United States)

    do Nascimento de Freitas, Deise; Gassen, Rodrigo Benedetti; Fazolo, Tiago; Souza, Ana Paula Duarte de

    2016-10-01

    The macrolide rapamycin inhibits mTOR (mechanist target of rapamycin) function and has been broadly used to unveil the role of mTOR in immune responses. Inhibition of mTOR on dendritic cells (DC) can influence cellular immune response and the survival of DC. RSV is the most common cause of hospitalization in infants and is a high priority candidate to vaccine development. In this study we showed that rapamycin treatment on RSV-infected murine bone marrow-derived DC (BMDC) decreases the frequency of CD8(+)CD44(high) T cells. However, inhibition of mTOR on RSV-infected BMDC did not modify the activation phenotype of these cells. RSV-RNA levels increase when infected BMDC were treated with rapamycin. Moreover, we observed that rapamycin diminishes apoptosis cell death of RSV-infected BMDC co-culture with T cells and this effect was abolished when the cells were co-cultured in a transwell system that prevents cell-to-cell contact or migration. Taken together, these data indicate that rapamycin treatment present a toxic effect on RSV-infected BMDC increasing RSV-RNA levels, affecting partially CD8 T cell differentiation and also increasing BMDC survival in a mechanism dependent on T cell contact.

  3. Chronic schistosomiasis during pregnancy epigenetically reprograms T-cell differentiation in offspring of infected mothers.

    Science.gov (United States)

    Klar, Kathrin; Perchermeier, Sophie; Bhattacharjee, Sonakshi; Harb, Hani; Adler, Thure; Istvanffy, Rouzanna; Loffredo-Verde, Eva; R A Oostendorp, Robert; Renz, Harald; Prazeres da Costa, Clarissa

    2017-05-01

    Schistosomiasis is a nontransplacental helminth infection. Chronic infection during pregnancy suppresses allergic airway responses in offspring. We addressed the question whether in utero exposure to chronic schistosome infection (Reg phase) in mice affects B-cell and T-cell development. Therefore, we focused our analyses on T-cell differentiation capacity induced by epigenetic changes in promoter regions of signature cytokines in offspring. Here, we show that naïve T cells from offspring of schistosome infected female mice had a strong capacity to differentiate into TH 1 cells, whereas TH 2 differentiation was impaired. In accordance, reduced levels of histone acetylation of the IL-4 promoter regions were observed in naïve T cells. To conclude, our mouse model revealed distinct epigenetic changes within the naïve T-cell compartment affecting TH 2 and TH 1 cell differentiation in offspring of mothers with chronic helminth infection. These findings could eventually help understand how helminths alter T-cell driven immune responses induced by allergens, bacterial or viral infections, as well as vaccines. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Changes in Circulating B Cell Subsets Associated with Aging and Acute SIV Infection in Rhesus Macaques

    Science.gov (United States)

    Gonzalez, Denise F.; Kieu, Hung T.; Castillo, Luis D.; Messaoudi, Ilhem; Shen, Xiaoying; Tomaras, Georgia D.; Shacklett, Barbara L.; Barry, Peter A.; Sparger, Ellen E.

    2017-01-01

    Aging and certain viral infections can negatively impact humoral responses in humans. To further develop the nonhuman primate (NHP) model for investigating B cell dynamics in human aging and infectious disease, a flow cytometric panel was developed to characterize circulating rhesus B cell subsets. Significant differences between human and macaque B cells included the proportions of cells within IgD+ and switched memory populations and a prominent CD21-CD27+ unswitched memory population detected only in macaques. We then utilized the expanded panel to analyze B cell alterations associated with aging and acute simian immunodeficiency virus (SIV) infection in the NHP model. In the aging study, distinct patterns of B cell subset frequencies were observed for macaques aged one to five years compared to those between ages 5 and 30 years. In the SIV infection study, B cell frequencies and absolute number were dramatically reduced following acute infection, but recovered within four weeks of infection. Thereafter, the frequencies of activated memory B cells progressively increased; these were significantly correlated with the magnitude of SIV-specific IgG responses, and coincided with impaired maturation of anti-SIV antibody avidity, as previously reported for HIV-1 infection. These observations further validate the NHP model for investigation of mechanisms responsible for B cells alterations associated with immunosenescence and infectious disease. PMID:28095513

  5. Rapid reactivation of extralymphoid CD4 T cells during secondary infection.

    Directory of Open Access Journals (Sweden)

    Timothy J Chapman

    Full Text Available After infection, extralymphoid tissues are enriched with effector and memory T cells of a highly activated phenotype. The capacity for rapid effector cytokine response from extralymphoid tissue-memory T cells suggests these cells may perform a 'sentinel' function in the tissue. While it has been demonstrated that extralymphoid CD4+ T cells can directly respond to secondary infection, little is known about how rapidly this response is initiated, and how early activation of T cells in the tissue may affect the innate response to infection. Here we use a mouse model of secondary heterosubtypic influenza infection to show that CD4(+ T cells in the lung airways are reactivated within 24 hours of secondary challenge. Airway CD4(+ T cells initiate an inflammatory cytokine and chemokine program that both alters the composition of the early innate response and contributes to the reduction of viral titers in the lung. These results show that, unlike a primary infection, extralymphoid tissue-memory CD4(+ T cells respond alongside the innate response during secondary infection, thereby shaping the overall immune profile in the airways. These data provide new insights into the role of extralymphoid CD4(+ T cells during secondary immune responses.

  6. CD4 T Follicular Helper Cells and HIV Infection: Friends or Enemies?

    Science.gov (United States)

    Moukambi, Félicien; Rodrigues, Vasco; Fortier, Yasmina; Rabezanahary, Henintsoa; Borde, Chloé; Krust, Bernard; Andreani, Guadalupe; Silvestre, Ricardo; Petrovas, Constantinos; Laforge, Mireille; Estaquier, Jérôme

    2017-01-01

    Follicular T helper (Tfh) cells, a subset of CD4 T lymphocytes, are essential for memory B cell activation, survival, and differentiation and assist B cells in the production of antigen-specific antibodies. Work performed in recent years pointed out the importance of Tfh cells in the context of HIV and SIV infections. The importance of tissue distribution of Tfh is also an important point since their frequency differs between peripheral blood and lymph nodes compared to the spleen, the primary organ for B cell activation, and differentiation. Our recent observations indicated an early and profound loss of splenic Tfh cells. The role of transcriptional activator and repressor factors that control Tfh differentiation is also discussed in the context of HIV/SIV infection. Because Tfh cells are important for B cell differentiation and antibody production, accelerating the Tfh responses early during HIV/SIV infection could be promising as novel immunotherapeutic approach or alternative vaccine strategies. However, because Tfh cells are infected during the HIV/SIV infection and represent a reservoir, this may interfere with HIV vaccine strategy. Thus, Tfh represent the good and bad guys during HIV infection.

  7. Effect of Salmonella infection on cecal tonsil regulatory T cell properties in chickens.

    Science.gov (United States)

    Shanmugasundaram, Revathi; Kogut, Michael H; Arsenault, Ryan J; Swaggerty, Christina L; Cole, Kimberly; Reddish, John M; Selvaraj, Ramesh K

    2015-08-01

    Two studies were conducted to study regulatory T cell [Treg (CD4⁺CD25⁺)] properties during the establishment of a persistent intestinal infection in broiler chickens. Four-day-old broiler chicks were orally gavaged with 5 × 10⁶ CFU/mL Salmonella enteritidis (S. enteritidis) or sterile PBS (control). Samples were collected at 4, 7, 10, and 14 d postinfection. There was a significant (P 0.05) when compared to that of noninfected control birds. At a lower effector/responder cell ratio of 0.25:1, CD4⁺CD25⁺ cells from cecal tonsils of Salmonella-infected birds suppressed T cell proliferation at d 7 and 14 post-S. enteritidis infection, while CD4⁺CD25⁺ cells from noninfected control groups did not suppress T cell proliferation. In the second studu, 1-day-old chickens were orally gavaged with PBS (control) or 1.25 × 10⁸ CFU/bird S. enteritidis. At 7 and 21 d post-Salmonella infection, CD25⁺ cells collected from cecal tonsils of S. enteritidis-infected birds and restimulated in vitro with Salmonella antigen had higher (P 0.05) between the Salmonella-infected and control birds. In conclusion, a persistent intestinal S. enteritidis infection increased the Treg percentage, suppressive properties, and IL-10 mRNA amounts in the cecal tonsils of broiler birds.

  8. T Cell Memory in the Context of Persistent Herpes Viral Infections

    Directory of Open Access Journals (Sweden)

    Nicole Torti

    2012-07-01

    Full Text Available The generation of a functional memory T cell pool upon primary encounter with an infectious pathogen is, in combination with humoral immunity, an essential process to confer protective immunity against reencounters with the same pathogen. A prerequisite for the generation and maintenance of long-lived memory T cells is the clearance of antigen after infection, which is fulfilled upon resolution of acute viral infections. Memory T cells play also a fundamental role during persistent viral infections by contributing to relative control and immuosurveillance of active replication or viral reactivation, respectively. However, the dynamics, the phenotype, the mechanisms of maintenance and the functionality of memory T cells which develop upon acute/resolved infection as opposed to chronic/latent infection differ substantially. In this review we summarize current knowledge about memory CD8 T cell responses elicited during α-, β-, and γ-herpes viral infections with major emphasis on the induction, maintenance and function of virus-specific memory CD8 T cells during viral latency and we discuss how the peculiar features of these memory CD8 T cell responses are related to the biology of these persistently infecting viruses.

  9. Anaplasma phagocytophilum Manipulates Host Cell Apoptosis by Different Mechanisms to Establish Infection

    Directory of Open Access Journals (Sweden)

    Pilar Alberdi

    2016-07-01

    Full Text Available Anaplasma phagocytophilum is an emerging zoonotic pathogen that causes human and animal granulocytic anaplasmosis and tick-borne fever of ruminants. This obligate intracellular bacterium evolved to use common strategies to establish infection in both vertebrate hosts and tick vectors. Herein, we discuss the different strategies used by the pathogen to modulate cell apoptosis and establish infection in host cells. In vertebrate neutrophils and human promyelocytic cells HL-60, both pro-apoptotic and anti-apoptotic factors have been reported. Tissue-specific differences in tick response to infection and differential regulation of apoptosis pathways have been observed in adult female midguts and salivary glands in response to infection with A. phagocytophilum. In tick midguts, pathogen inhibits apoptosis through the Janus kinase/signal transducers and activators of transcription (JAK/STAT pathway, while in salivary glands, the intrinsic apoptosis pathways is inhibited but tick cells respond with the activation of the extrinsic apoptosis pathway. In Ixodes scapularis ISE6 cells, bacterial infection down-regulates mitochondrial porin and manipulates protein processing in the endoplasmic reticulum and cell glucose metabolism to inhibit apoptosis and facilitate infection, whereas in IRE/CTVM20 tick cells, inhibition of apoptosis appears to be regulated by lower caspase levels. These results suggest that A. phagocytophilum uses different mechanisms to inhibit apoptosis for infection of both vertebrate and invertebrate hosts.

  10. CD31 is required on CD4+ T cells to promote T cell survival during Salmonella infection.

    Science.gov (United States)

    Ross, Ewan A; Coughlan, Ruth E; Flores-Langarica, Adriana; Bobat, Saeeda; Marshall, Jennifer L; Hussain, Khiyam; Charlesworth, James; Abhyankar, Nikita; Hitchcock, Jessica; Gil, Cristina; López-Macías, Constantino; Henderson, Ian R; Khan, Mahmood; Watson, Steve P; MacLennan, Ian C M; Buckley, Christopher D; Cunningham, Adam F

    2011-08-15

    Hematopoietic cells constitutively express CD31/PECAM1, a signaling adhesion receptor associated with controlling responses to inflammatory stimuli. Although expressed on CD4(+) T cells, its function on these cells is unclear. To address this, we have used a model of systemic Salmonella infection that induces high levels of T cell activation and depends on CD4(+) T cells for resolution. Infection of CD31-deficient (CD31KO) mice demonstrates that these mice fail to control infection effectively. During infection, CD31KO mice have diminished numbers of total CD4(+) T cells and IFN-γ-secreting Th1 cells. This is despite a higher proportion of CD31KO CD4(+) T cells exhibiting an activated phenotype and an undiminished capacity to prime normally and polarize to Th1. Reduced numbers of T cells reflected the increased propensity of naive and activated CD31KO T cells to undergo apoptosis postinfection compared with wild-type T cells. Using adoptive transfer experiments, we show that loss of CD31 on CD4(+) T cells alone is sufficient to account for the defective CD31KO T cell accumulation. These data are consistent with CD31 helping to control T cell activation, because in its absence, T cells have a greater propensity to become activated, resulting in increased susceptibility to become apoptotic. The impact of CD31 loss on T cell homeostasis becomes most pronounced during severe, inflammatory, and immunological stresses such as those caused by systemic Salmonella infection. This identifies a novel role for CD31 in regulating CD4 T cell homeostasis.

  11. Infection of Mosquito Cells (C6/36) by Dengue-2 Virus Interferes with Subsequent Infection by Yellow Fever Virus.

    Science.gov (United States)

    Abrao, Emiliana Pereira; da Fonseca, Benedito Antônio Lopes

    2016-02-01

    Dengue is one of the most important diseases caused by arboviruses in the world. Yellow fever is another arthropod-borne disease of great importance to public health that is endemic to tropical regions of Africa and the Americas. Both yellow fever and dengue viruses are flaviviruses transmitted by Aedes aegypti mosquitoes, and then, it is reasonable to consider that in a given moment, mosquito cells could be coinfected by both viruses. Therefore, we decided to evaluate if sequential infections of dengue and yellow fever viruses (and vice-versa) in mosquito cells could affect the virus replication patterns. Using immunofluorescence and real-time PCR-based replication assays in Aedes albopictus C6/36 cells with single or sequential infections with both viruses, we demonstrated the occurrence of viral interference, also called superinfection exclusion, between these two viruses. Our results show that this interference pattern is particularly evident when cells were first infected with dengue virus and subsequently with yellow fever virus (YFV). Reduction in dengue virus replication, although to a lower extent, was also observed when C6/36 cells were initially infected with YFV followed by dengue virus infection. Although the importance that these findings have on nature is unknown, this study provides evidence, at the cellular level, of the occurrence of replication interference between dengue and yellow fever viruses and raises the question if superinfection exclusion could be a possible explanation, at least partially, for the reported lack of urban yellow fever occurrence in regions where a high level of dengue transmission occurs.

  12. Characterization of epstein-barr virus-infected mantle cell lymphoma lines.

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    Jin Z

    2000-10-01

    Full Text Available It has been reported that Epstein-Barr virus (EBV resides in resting B cells in vivo. However, an ideal in vitro system for studying EBV latent infection in vivo has not yet been established. In this study, a mantle cell lymphoma line, SP53, was successfully infected with a recombinant EBV containing a neomycin-resistant gene. The EBV-carrying SP53 cells were obtained by selection using G418. They expressed EBER-1, EBNAs, and LMP1; this expression pattern of the EBV genes was similar to that in a lymphoblastoid cell line (LCL. However, proliferation assay showed that the EBV-carrying SP53 cells have a doubling time of 73 h, compared with 57 h of SP53 cells. Transplantation of 10(8 SP53 cells to nude mice formed tumors in 4 of 10 mice inoculated, but the EBV-carrying SP53 cells did not. Unexpectedly, EBV infection reduced the proliferation and tumorigenicity of SP53 cells. However, the EBV-carrying SP53 cells showed higher resistance to apoptosis induced by serum starvation than did the SP53 cells. The inhibition of proliferation and the resistance to apoptosis induced in SP53 cells by EBV infection indicate that this cell line might to some extent provide a model of in vivo EBV reservoir cells.

  13. Temporal proteomic profiling of Chlamydia trachomatis-infected HeLa-229 human cervical epithelial cells.

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    Tan, Grace Min Yi; Lim, Hui Jing; Yeow, Tee Cian; Movahed, Elaheh; Looi, Chung Yeng; Gupta, Rishein; Arulanandam, Bernard P; Abu Bakar, Sazaly; Sabet, Negar Shafiei; Chang, Li-Yen; Wong, Won Fen

    2016-05-01

    Chlamydia trachomatis is the leading causative agent of bacterial sexually transmitted infections worldwide which can lead to female pelvic inflammatory disease and infertility. A greater understanding of host response during chlamydial infection is essential to design intervention technique to reduce the increasing incidence rate of genital chlamydial infection. In this study, we investigated proteome changes in epithelial cells during C. trachomatis infection by using an isobaric tags for relative and absolute quantitation (iTRAQ) labeling technique coupled with a liquid chromatography-tandem mass spectrometry (LC-MS(3) ) analysis. C. trachomatis (serovar D, MOI 1)-infected HeLa-229 human cervical carcinoma epithelial cells (at 2, 4 and 8 h) showed profound modifications of proteome profile which involved 606 host proteins. MGST1, SUGP2 and ATXN10 were among the top in the list of the differentially upregulated protein. Through pathway analysis, we suggested the involvement of eukaryotic initiation factor 2 (eIF2) and mammalian target of rapamycin (mTOR) in host cells upon C. trachomatis infection. Network analysis underscored the participation of DNA repair mechanism during C. trachomatis infection. In summary, intense modifications of proteome profile in C. trachomatis-infected HeLa-229 cells indicate complex host-pathogen interactions at early phase of chlamydial infection.

  14. The circadian clock in immune cells controls the magnitude of Leishmania parasite infection.

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    Kiessling, Silke; Dubeau-Laramée, Geneviève; Ohm, Hyejee; Labrecque, Nathalie; Olivier, Martin; Cermakian, Nicolas

    2017-09-07

    The intracellular parasite Leishmania uses neutrophils and macrophages as host cells upon infection. These immune cells harbour their own intrinsic circadian clocks, known to influence many aspects of their functions. Therefore, we tested whether the host circadian clocks regulate the magnitude of Leishmania major infection in mice. The extent of parasitic infection varied over 24 h in bone marrow-derived macrophages in vitro and in two different in vivo models, footpad and peritoneal cavity infection. In vivo this was paralleled by time of day-dependent neutrophil and macrophage infiltration to the infection site and rhythmic chemokine expression. Thus, rhythmic parasitic infection observed in vivo was likely initiated by the circadian expression of chemoattractants and the subsequent rhythmic infiltration of neutrophils and macrophages. Importantly, all rhythms were abolished in clock-deficient macrophages and when mice lacking the circadian clock in immune cells were infected. Therefore we demonstrated a critical role for the circadian clocks in immune cells in modulating the magnitude of Leishmania infection. To our knowledge this is the first report showing that the circadian clock controls infection by protozoan parasites in mammals. Understanding the timed regulation of host-parasite interactions will allow developing better prophylactic and therapeutic strategies to fight off vector-borne diseases.

  15. RNAi screen in Drosophila cells reveals the involvement of the Tom complex in Chlamydia infection.

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    Isabelle Derré

    2007-10-01

    Full Text Available Chlamydia spp. are intracellular obligate bacterial pathogens that infect a wide range of host cells. Here, we show that C. caviae enters, replicates, and performs a complete developmental cycle in Drosophila SL2 cells. Using this model system, we have performed a genome-wide RNA interference screen and identified 54 factors that, when depleted, inhibit C. caviae infection. By testing the effect of each candidate's knock down on L. monocytogenes infection, we have identified 31 candidates presumably specific of C. caviae infection. We found factors expected to have an effect on Chlamydia infection, such as heparansulfate glycosaminoglycans and actin and microtubule remodeling factors. We also identified factors that were not previously described as involved in Chlamydia infection. For instance, we identified members of the Tim-Tom complex, a multiprotein complex involved in the recognition and import of nuclear-encoded proteins to the mitochondria, as required for C. caviae infection of Drosophila cells. Finally, we confirmed that depletion of either Tom40 or Tom22 also reduced C. caviae infection in mammalian cells. However, C. trachomatis infection was not affected, suggesting that the mechanism involved is C. caviae specific.

  16. Effect of cell culture system on the production of human viral antigens Efeito do sistema de cultura celular na produção de antígenos virais humanos

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    Ronaldo Zucatelli Mendonça

    2004-06-01

    Full Text Available A comparative study was performed in the production of different viral antigens by using microcarrier systems and traditional systems. Vero, BHK and MA 104 cells were cultivated in microcarriers (2mg/ml using a bioreactor with a working capacity of 3.7 liters, in parallel with conventional Roux bottles. After four days (BHK cells, and seven days of culture (Vero and MA-104 cells, the cells were infected with 0.1 MOI (multiplicity of infection of rabies virus, measles virus, poliovirus and rotavirus. The yields of the cells and virus in microcarriers and in the conventional system were determined. It was observed that in the microcarrier system, an average increase of twenty-fold more cells/ml was obtained in relation to the conventional monolayer culture, using Roux bottle. On the other hand, cells grown in Roux bottles presented 1.3 to 6.7 more viruses/ml culture than those in the microcarrier systems. However, the overall data showed that yieldings, in terms of viruses per batch, were statistically similar for both systems (p > 0.05. The amount of viral antigen production seems to depend not only on cell concentration, but also on other culture factors such as the characteristic of the cell-growth surface. Thus, the present findings provide a baseline for further improvements and strategies to be established for a scaling-up virus production since depending on the type of virus the optimal conditions found for a small-scale virus production seem unsuitable for large-scale production, requiring new standardization and evaluation.Foi realizado estudo comparativo na produção de diferentes antígenos virais usando sistema de microcarregador e sistema tradicional. Células Vero, BHK e MA-104 foram cultivadas em microcarregadores (2mg/ml utilizando-se biorreatores com capacidade de 3,7 litros e, em paralelo, no sistema convencional com garrafas Roux. Após quatro dias de cultura para as células BHK e sete dias para as células Vero e MA-104, as c

  17. Free-virus and cell-to-cell transmission in models of equine infectious anemia virus infection.

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    Allen, Linda J S; Schwartz, Elissa J

    2015-12-01

    Equine infectious anemia virus (EIAV) is a lentivirus in the retrovirus family that infects horses and ponies. Two strains, referred to as the sensitive strain and the resistant strain, have been isolated from an experimentally-infected pony. The sensitive strain is vulnerable to neutralization by antibodies whereas the resistant strain is neutralization-insensitive. The sensitive strain mutates to the resistant strain. EIAV may infect healthy target cells via free virus or alternatively, directly from an infected target cell through cell-to-cell transfer. The proportion of transmission from free-virus or from cell-to-cell transmission is unknown. A system of ordinary differential equations (ODEs) is formulated for the virus-cell dynamics of EIAV. In addition, a Markov chain model and a branching process approximation near the infection-free equilibrium (IFE) are formulated. The basic reproduction number R0 is defined as the maximum of two reproduction numbers, R0s and R0r, one for the sensitive strain and one for the resistant strain. The IFE is shown to be globally asymptotically stable for the ODE model in a special case when the basic reproduction number is less than one. In addition, two endemic equilibria exist, a coexistence equilibrium and a resistant strain equilibrium. It is shown that if R0>1, the infection persists with at least one of the two strains. However, for small infectious doses, the sensitive strain and the resistant strain may not persist in the Markov chain model. Parameter values applicable to EIAV are used to illustrate the dynamics of the ODE and the Markov chain models. The examples highlight the importance of the proportion of cell-to-cell versus free-virus transmission that either leads to infection clearance or to infection persistence with either coexistence of both strains or to dominance by the resistant strain. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. CIITA enhances HIV-1 attachment to CD4+ T cells leading to enhanced infection and cell depletion.

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    Porter, Kristen A; Kelley, Lauren N; Nekorchuk, Michael D; Jones, James H; Hahn, Amy B; de Noronha, Carlos M C; Harton, Jonathan A; Duus, Karen M

    2010-12-01

    Activated CD4(+) T cells are more susceptible to HIV infection than resting T cells; the reason for this remains unresolved. Induction of CIITA and subsequent expression of the MHC class II isotype HLA-DR are hallmarks of CD4(+) T cell activation; therefore, we investigated the role of CIITA expression in T cells during HIV infection. CIITA-expressing SupT1 cells display enhanced virion attachment in a gp160/CD4-dependent manner, which results in increased HIV infection, virus release, and T cell depletion. Although increased attachment and infection of T cells correlated with HLA-DR surface expression, Ab blocking, transient expression of HLA-DR without CIITA, and short hairpin RNA knockdown demonstrate that HLA-DR does not directly enhance susceptibility of CIITA-expressing cells to HIV infection. Further analysis of the remaining MHC class II isotypes, HLA-DP and HLA-DQ, MHC class I isotypes, HLA-A, HLA-B, and HLA-C, and the class II Ag presentation genes, invariant chain and HLA-DM, demonstrate that these proteins likely do not contribute to CIITA enhancement of HIV infection. Finally, we demonstrate that in activated primary CD4(+) T cells as HLA-DR/CIITA expression increases there is a corresponding increase in virion attachment. Overall, this work suggests that induction of CIITA expression upon CD4(+) T cell activation contributes to enhanced attachment, infection, virus release, and cell death through an undefined CIITA transcription product that may serve as a new antiviral target.

  19. Infection kinetics of human adenovirus serotype 41 in HEK 293 cells

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    Joselma Siqueira-Silva

    2009-08-01

    Full Text Available The purpose of this work was to acquire an overview of the infectious cycle of HAdV-41 in permissive HEK 293 cells and compare it to that observed with the prototype of the genus, Human adenovirus C HAdV-2. HEK 293 cells were infected with each virus separately and were harvested every 12 h for seven days. Infection kinetics were analysed using confocal and electronic microscopy. The results show that, when properly cultivated, HAdV-41 was not fastidious. It had a longer multiplication cycle, which resulted in the release of complete viral particles and viral stocks reached high titres. After 60 h of infection, the export of viral proteins from the infected cell to the extracellular milieu was observed, with a pattern similar to that previously described for HAdV-2 penton-base trafficking after 30 h of infection. HAdV-41 had a non-lytic cycle and the infection spread from the first infected cell to its neighbours. The release process of the viral particles is unknown. The results observed for HAdV-41 infection in HEK 293 cells show how different this virus is from the prototype HAdV-2 and provides information for the development of this vector for use in gene therapy.

  20. HIV-1 infection initiates an inflammatory cascade in human renal tubular epithelial cells.

    Science.gov (United States)

    Ross, Michael J; Fan, Cheng; Ross, Michael D; Chu, Te-Huatearina; Shi, Yueyue; Kaufman, Lewis; Zhang, Weijia; Klotman, Mary E; Klotman, Paul E

    2006-05-01

    HIV-associated nephropathy (HIVAN) is the most common cause of chronic renal failure in HIV-infected patients. Tubulointerstitial inflammation is a prominent component of the histopathology of HIVAN. The pathogenesis of HIVAN is a result of infection of renal epithelial cells, but the cellular response to this infection remains poorly defined. In these studies, we used oligonucleotide microarrays to identify differentially expressed genes in renal tubular epithelial cells from a patient with HIVAN at three time points after infection with vesicular stomatitis virus-pseudotyped gag/pol-deleted HIV-1. Very few genes were differentially expressed 12 and 24 hours after infection. Three days after infection, however, 47 genes were upregulated by at least 1.8-fold. The most prominent response of these cells to HIV-1 expression was production of proinflammatory mediators, including chemokines, cytokines, and adhesion molecules. Many of the upregulated genes are targets of interleukin 6 and nuclear factor kappa B regulation, suggesting a central role for these proteins in the response of tubular epithelial cells to HIV-1 infection. Analysis of kidneys from HIV-1 transgenic mice revealed upregulation of many of the proinflammatory genes identified in the microarray studies. These studies provide novel insights into the mechanisms by which HIV-1 infection of tubular epithelial cells leads to tubulointerstitial inflammation and progressive renal injury.

  1. Chloroquine, an Endocytosis Blocking Agent, Inhibits Zika Virus Infection in Different Cell Models.

    Science.gov (United States)

    Delvecchio, Rodrigo; Higa, Luiza M; Pezzuto, Paula; Valadão, Ana Luiza; Garcez, Patrícia P; Monteiro, Fábio L; Loiola, Erick C; Dias, André A; Silva, Fábio J M; Aliota, Matthew T; Caine, Elizabeth A; Osorio, Jorge E; Bellio, Maria; O'Connor, David H; Rehen, Stevens; de Aguiar, Renato Santana; Savarino, Andrea; Campanati, Loraine; Tanuri, Amilcar

    2016-11-29

    Zika virus (ZIKV) infection in utero might lead to microcephaly and other congenital defects. Since no specific therapy is available thus far, there is an urgent need for the discovery of agents capable of inhibiting its viral replication and deleterious effects. Chloroquine is widely used as an antimalarial drug, anti-inflammatory agent, and it also shows antiviral activity against several viruses. Here we show that chloroquine exhibits antiviral activity against ZIKV in Vero cells, human brain microvascular endothelial cells, human neural stem cells, and mouse neurospheres. We demonstrate that chloroquine reduces the number of ZIKV-infected cells in vitro, and inhibits virus production and cell death promoted by ZIKV infection without cytotoxic effects. In addition, chloroquine treatment partially reveres morphological changes induced by ZIKV infection in mouse neurospheres.

  2. On the birefringence of healthy and malaria-infected red blood cells

    CERN Document Server

    Dharmadhikari, Aditya K; Dharmadhikari, Jayashree A; Sharma, Shobhona; Mathur, Deepak

    2013-01-01

    We have probed how the birefringence of a healthy red blood cell (RBC) changes as it becomes infected by a malarial parasite. By analyzing the polarization properties of light transmitted through a single, optically-trapped cell we demarcate two types of birefringence: form birefringence which depends on the shape of the cell and intrinsic birefringence which is brought about by the presence of the parasite. We quantitatively measure changes in the refractive index as normal RBS become infected by a malarial parasite. Malarial infections are found to induce changes in the cell's refractive index whose magnitude depends on the stage of malarial infection; such changes were quantitatively explored and found to be large, in the range 1.2 to 3$\\times10^{-2}$. Our results have implications for the development and use of non-invasive techniques that seek to quantify changes in cell properties induced by pathological states accompanying diseases like malaria. From a broader prespective, information forthcoming from ...

  3. Chloroquine, an Endocytosis Blocking Agent, Inhibits Zika Virus Infection in Different Cell Models

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    Rodrigo Delvecchio

    2016-11-01

    Full Text Available Zika virus (ZIKV infection in utero might lead to microcephaly and other congenital defects. Since no specific therapy is available thus far, there is an urgent need for the discovery of agents capable of inhibiting its viral replication and deleterious effects. Chloroquine is widely used as an antimalarial drug, anti-inflammatory agent, and it also shows antiviral activity against several viruses. Here we show that chloroquine exhibits antiviral activity against ZIKV in Vero cells, human brain microvascular endothelial cells, human neural stem cells, and mouse neurospheres. We demonstrate that chloroquine reduces the number of ZIKV-infected cells in vitro, and inhibits virus production and cell death promoted by ZIKV infection without cytotoxic effects. In addition, chloroquine treatment partially reveres morphological changes induced by ZIKV infection in mouse neurospheres.

  4. Targeting of liposomes to HIV-1-infected cells by peptides derived from the CD4 receptor.

    Science.gov (United States)

    Slepushkin, V A; Salem, I I; Andreev, S M; Dazin, P; Düzgüneş, N

    1996-10-23

    Liposomes can be targeted to HIV-infected cells by either reconstituting transmembrane CD4 in the membrane or covalently coupling soluble CD4 to modified lipids. We investigated whether synthetic peptides could be used as ligands for targeting liposomes. A synthetic peptide from the complementarity determining region 2 (CDR-2)-like domain of CD4 could bind specifically to HIV-infected cells and mediate the binding of peptide-coupled liposomes to these cells. A peptide from the CDR-3-like domain of CD4 inhibited HIV-induced syncytia formation, but failed to target liposomes to infected cells. This apparent discrepancy may be due to the requirement for a conformational change in the CD4 receptor for the CDR-3 region to interact with the HIV envelope protein. Our results demonstrate the feasibility of using synthetic peptides to target liposomes containing antiviral drugs to HIV-infected cells.

  5. Activated iNKT cells promote memory CD8+ T cell differentiation during viral infection.

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    Emma C Reilly

    Full Text Available α-Galactosylceramide (α-GalCer is the prototypical lipid ligand for invariant NKT cells. Recent studies have proposed that α-GalCer is an effective adjuvant in vaccination against a range of immune challenges, however its mechanism of action has not been completely elucidated. A variety of delivery methods have been examined including pulsing dendritic cells with α-GalCer to optimize the potential of α-GalCer. These methods are currently being used in a variety of clinical trials in patients with advanced cancer but cannot be used in the context of vaccine development against pathogens due to their complexity. Using a simple delivery method, we evaluated α-GalCer adjuvant properties, using the mouse model for cytomegalovirus (MCMV. We measured several key parameters of the immune response to MCMV, including inflammation, effector, and central memory CD8(+ T cell responses. We found that α-GalCer injection at the time of the infection decreases viral titers, alters the kinetics of the inflammatory response, and promotes both increased frequencies and numbers of virus-specific memory CD8(+ T cells. Overall, our data suggest that iNKT cell activation by α-GalCer promotes the development of long-term protective immunity through increased fitness of central memory CD8(+ T cells, as a consequence of reduced inflammation.

  6. Sp110 transcription is induced and required by Anaplasma phagocytophilum for infection of human promyelocytic cells

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    Naranjo Victoria

    2007-09-01

    Full Text Available Abstract Background The tick-borne intracellular pathogen, Anaplasma phagocytophilum (Rickettsiales: Anaplasmataceae causes human granulocytic anaplasmosis after infection of polymorphonuclear leucocytes. The human Sp110 gene is a member of the nuclear body (NB components that functions as a nuclear hormone receptor transcriptional coactivator and plays an important role in immunoprotective mechanisms against pathogens in humans. In this research, we hypothesized that Sp110 may be involved in the infection of human promyelocytic HL-60 cells with A. phagocytophilum. Methods The human Sp110 and A. phagocytophilum msp4 mRNA levels were evaluated by real-time RT-PCR in infected human HL-60 cells sampled at 0, 12, 24, 48, 72 and 96 hours post-infection. The effect of Sp110 expression on A. phagocytophilum infection was determined by RNA interference (RNAi. The expression of Sp110 was silenced in HL-60 cells by RNAi using pre-designed siRNAs using the Nucleofector 96-well shuttle system (Amaxa Biosystems, Gaithersburg, MD, USA. The A. phagocytophilum infection levels were evaluated in HL-60 cells after RNAi by real-time PCR of msp4 and normalizing against human Alu sequences. Results While Sp110 mRNA levels increased concurrently with A. phagocytophilum infections in HL-60 cells, the silencing of Sp110 expression by RNA interference resulted in decreased infection levels. Conclusion These results demonstrated that Sp110 expression is required for A. phagocytophilum infection and multiplication in HL-60 cells, and suggest a previously undescribed mechanism by which A. phagocytophilum modulates Sp110 mRNA levels to facilitate establishment of infection of human HL-60 cells.

  7. The Differentiation and Protective Function of Cytolytic CD4 T Cells in Influenza Infection

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    Deborah M. Brown

    2016-03-01

    Full Text Available CD4 T cells that recognize peptide antigen in the context of Class II MHC can differentiate into various subsets that are characterized by their helper functions. However, increasing evidence indicates that CD4 cells with direct cytolytic activity (CD4 CTL play a role in chronic, as well as, acute infections such as influenza A virus (IAV infection. In the last couple of decades, techniques to measure the frequency and activity of these cytolytic cells has demonstrated their abundance in infections such as HIV, mouse pox, murine gamma herpes virus, CMV, EBV and influenza among others. We now appreciate a greater role for CD4 CTL as direct effectors in viral infections and anti-tumor immunity through their ability to acquire perforin mediated cytolytic activity and contribution to lysis of virally infected targets or tumors. As early as the 1980s, CD4 T cell clones with cytolytic potential were identified after influenza virus infection, yet much of this early work was dependent on in vitro culture and little was known about the physiological relevance of CD4 CTL. Here, we discuss the direct role CD4 CTL play in protection against lethal IAV infection and the factors that drive the generation of perforin mediated lytic activity in CD4 cells in vivo during IAV infection. While focusing on CD4 CTL generated during IAV infection, we pull comparisons from the literature in other anti-viral and anti-tumor systems. Further, we highlight what is currently known about CD4 CTL secondary and memory responses, as well as vaccination strategies to induce these potent killer cells that provide an extra layer of cell mediated immune protection against heterosubtypic IAV infection.

  8. Murine cytomegalovirus infection of neural stem cells alters neurogenesis in the developing brain.

    Science.gov (United States)

    Mutnal, Manohar B; Cheeran, Maxim C-J; Hu, Shuxian; Lokensgard, James R

    2011-01-13

    Congenital cytomegalovirus (CMV) brain infection causes serious neuro-developmental sequelae including: mental retardation, cerebral palsy, and sensorineural hearing loss. But, the mechanisms of injury and pathogenesis to the fetal brain are not completely understood. The present study addresses potential pathogenic mechanisms by which this virus injures the CNS using a neonatal mouse model that mirrors congenital brain infection. This investigation focused on, analysis of cell types infected with mouse cytomegalovirus (MCMV) and the pattern of injury to the developing brain. We used our MCMV infection model and a multi-color flow cytometry approach to quantify the effect of viral infection on the developing brain, identifying specific target cells and the consequent effect on neurogenesis. In this study, we show that neural stem cells (NSCs) and neuronal precursor cells are the principal target cells for MCMV in the developing brain. In addition, viral infection was demonstrated to cause a loss of NSCs expressing CD133 and nestin. We also showed that infection of neonates leads to subsequent abnormal brain development as indicated by loss of CD24(hi) cells that incorporated BrdU. This neonatal brain infection was also associated with altered expression of Oct4, a multipotency marker; as well as down regulation of the neurotrophins BDNF and NT3, which are essential to regulate the birth and differentiation of neurons during normal brain development. Finally, we report decreased expression of doublecortin, a marker to identify young neurons, following viral brain infection. MCMV brain infection of newborn mice causes significant loss of NSCs, decreased proliferation of neuronal precursor cells, and marked loss of young neurons.

  9. Murine cytomegalovirus infection of neural stem cells alters neurogenesis in the developing brain.

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    Manohar B Mutnal

    Full Text Available BACKGROUND: Congenital cytomegalovirus (CMV brain infection causes serious neuro-developmental sequelae including: mental retardation, cerebral palsy, and sensorineural hearing loss. But, the mechanisms of injury and pathogenesis to the fetal brain are not completely understood. The present study addresses potential pathogenic mechanisms by which this virus injures the CNS using a neonatal mouse model that mirrors congenital brain infection. This investigation focused on, analysis of cell types infected with mouse cytomegalovirus (MCMV and the pattern of injury to the developing brain. METHODOLOGY/PRINCIPAL FINDINGS: We used our MCMV infection model and a multi-color flow cytometry approach to quantify the effect of viral infection on the developing brain, identifying specific target cells and the consequent effect on neurogenesis. In this study, we show that neural stem cells (NSCs and neuronal precursor cells are the principal target cells for MCMV in the developing brain. In addition, viral infection was demonstrated to cause a loss of NSCs expressing CD133 and nestin. We also showed that infection of neonates leads to subsequent abnormal brain development as indicated by loss of CD24(hi cells that incorporated BrdU. This neonatal brain infection was also associated with altered expression of Oct4, a multipotency marker; as well as down regulation of the neurotrophins BDNF and NT3, which are essential to regulate the birth and differentiation of neurons during normal brain development. Finally, we report decreased expression of doublecortin, a marker to identify young neurons, following viral brain infection. CONCLUSIONS: MCMV brain infection of newborn mice causes significant loss of NSCs, decreased proliferation of neuronal precursor cells, and marked loss of young neurons.

  10. Comparison of in vitro cell culture and a mouse assay for measuring infectivity of Cryptosporidium parvum.

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    Rochelle, Paul A; Marshall, Marilyn M; Mead, Jan R; Johnson, Anne M; Korich, Dick G; Rosen, Jeffrey S; De Leon, Ricardo

    2002-08-01

    In vitro cell cultures were compared to neonatal mice for measuring the infectivity of five genotype 2 isolates of Cryptosporidium parvum. Oocyst doses were enumerated by flow cytometry and delivered to animals and cell monolayers by using standardized procedures. Each dose of oocysts was inoculated into up to nine replicates of 9 to 12 mice or 6 to 10 cell culture wells. Infections were detected by hematoxylin and eosin staining in CD-1 mice, by reverse transcriptase PCR in HCT-8 and Caco-2 cells, and by immunofluorescence microscopy in Madin-Darby canine kidney (MDCK) cells. Infectivity was expressed as a logistic transformation of the proportion of animals or cell culture wells that developed infection at each dose. In most instances, the slopes of the dose-response curves were not significantly different when we compared the infectivity models for each isolate. The 50% infective doses for the different isolates varied depending on the method of calculation but were in the range from 16 to 347 oocysts for CD-1 mice and in the ranges from 27 to 106, 31 to 629, and 13 to 18 oocysts for HCT-8, Caco-2, and MDCK cells, respectively. The average standard deviations for the percentages of infectivity for all replicates of all isolates were 13.9, 11.5, 13.2, and 10.7% for CD-1 mice, HCT-8 cells, Caco-2 cells, and MDCK cells, respectively, demonstrating that the levels of variability were similar in all assays. There was a good correlation between the average infectivity for HCT-8 cells and the results for CD-1 mice across all isolates for untreated oocysts (r = 0.85, n = 25) and for oocysts exposed to ozone and UV light (r = 0.89, n = 29). This study demonstrated that in vitro cell culture was equivalent to the "gold standard," mouse infectivity, for measuring the infectivity of C. parvum and should therefore be considered a practical and accurate alternative for assessing oocyst infectivity and inactivation. However, the high levels of variability displayed by all

  11. Chitin recognition via chitotriosidase promotes pathologic type-2 helper T cell responses to cryptococcal infection.

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    Darin L Wiesner

    2015-03-01

    Full Text Available Pulmonary mycoses are often associated with type-2 helper T (Th2 cell responses. However, mechanisms of Th2 cell accumulation are multifactorial and incompletely known. To investigate Th2 cell responses to pulmonary fungal infection, we developed a peptide-MHCII tetramer to track antigen-specific CD4+ T cells produced in response to infection with the fungal pathogen Cryptococcus neoformans. We noted massive accruement of pathologic cryptococcal antigen-specific Th2 cells in the lungs following infection that was coordinated by lung-resident CD11b+ IRF4-dependent conventional dendritic cells. Other researchers have demonstrated that this dendritic cell subset is also capable of priming protective Th17 cell responses to another pulmonary fungal infection, Aspergillus fumigatus. Thus, higher order detection of specific features of fungal infection by these dendritic cells must direct Th2 cell lineage commitment. Since chitin-containing parasites commonly elicit Th2 responses, we hypothesized that recognition of fungal chitin is an important determinant of Th2 cell-mediated mycosis. Using C. neoformans mutants or purified chitin, we found that chitin abundance impacted Th2 cell accumulation and disease. Importantly, we determined Th2 cell induction depended on cleavage of chitin via the mammalian chitinase, chitotriosidase, an enzyme that was also prevalent in humans experiencing overt cryptococcosis. The data presented herein offers a new perspective on fungal disease susceptibility, whereby chitin recognition via chitotriosidase leads to the initiation of harmful Th2 cell differentiation by CD11b+ conventional dendritic cells in response to pulmonary fungal infection.

  12. Human T cell leukemia/lymphoma virus type I infection of a CD4+ proliferative/cytotoxic T cell clone progresses in at least two distinct phases based on changes in function and phenotype of the infected cells.

    Science.gov (United States)

    Yssel, H; de Waal Malefyt, R; Duc Dodon, M D; Blanchard, D; Gazzolo, L; de Vries, J E; Spits, H

    1989-04-01

    The effect of human T cell leukemia/lymphoma virus type I (HTLV-I) infection on the function and the phenotype of a human proliferating/cytotoxic T cell clone, specific for tetanus toxin, was investigated. During the period after infection, two distinct phases were observed, based on growth properties, phenotype, and functional activity of the infected cells. Phase I HTLV-I infected cells (0 to about 150 days after infection) proliferated in an IL-2-dependent way, but without the requirement for repetitive antigenic stimulation. No differences in expression of the CD2, CD3, CD4, Tp103, and CD28 Ag between these cells and the parental cells could be demonstrated, with the exception of the expression of IL-R p55 and HLA-DR Ag, which were constitutively expressed on the phase I cells. The phase I HTLV-I-infected cells, as well as the parental 827 cells reacted with a mAb specific for an epitope on the variable part of the TCR beta-chain, indicating that the TCR was not altered after HTLV-I infection. Like the parental clone, the phase I cells proliferated in response to tetanus toxin, but the tetanus toxin-specific response of the phase I cells did not require the presence of APC. Results of experiments, in which the levels of intracellular Ca2+ were measured, indicated that HTLV-I cells can acquire the capability to process Ag and present that to themselves. Phase I HTLV-I-infected T cells had lost their cytotoxic activity which was likely to be due to an effect on the lytic machinery rather than on Ag recognition by the TCR, inasmuch as it was found that phase I HTLV-I-infected T cells did no longer contain N-alpha-benzyloxy-L-lysine thiobenzylester-serine esterase activity. Furthermore, it was found that phase I HTLV-I-infected T cells had a diminished capacity to form conjugates with target cells. From a period of about 200 days after HTLV-I infection, phase II cells emerged that proliferated strongly in the absence of IL-2 and that had lost all functional

  13. The impact of inflammation and immune activation on B cell differentiation during HIV-1 infection.

    Science.gov (United States)

    Ruffin, Nicolas; Thang, Pham Hong; Rethi, Bence; Nilsson, Anna; Chiodi, Francesca

    2011-01-01

    One important pathogenic feature of human immunodeficiency virus (HIV)-1 infection is chronic immune activation and impaired survival of T and B cells. A decline of resting memory B cells was reported to occur in both children and adults infected with HIV-1; these cells are responsible for maintaining an adequate serological response to antigens previously encountered in life through natural infection or vaccination. Further understanding of the mechanisms leading to impaired B cell differentiation and germinal center reaction might be essential to design new HIV vaccines and therapies that could improve humoral immune responses in HIV-1 infected individuals. In the present article we summarize the literature and present our view on critical mechanisms of B cell development impaired during HIV-1 infection. We also discuss the impact of microbial translocation, a driving force for persistent inflammation during HIV-1 infection, on survival of terminally differentiated B cells and how the altered expression of cytokines/chemokines pivotal for communication between T and B cells in lymphoid tissues may impair formation of memory B cells.

  14. Salmonella typhimurium infection increases p53 acetylation in intestinal epithelial cells.

    Science.gov (United States)

    Wu, Shaoping; Ye, Zhongde; Liu, Xingyin; Zhao, Yun; Xia, Yinglin; Steiner, Andrew; Petrof, Elaine O; Claud, Erika C; Sun, Jun

    2010-05-01

    The ability of Salmonella typhimurium to enter intestinal epithelial cells constitutes a crucial step in pathogenesis. Salmonella invasion of the intestinal epithelium requires bacterial type three secretion system. Type three secretion system is a transport device that injects virulence proteins, called effectors, to paralyze or reprogram the eukaryotic cells. Avirulence factor for Salmonella (AvrA) is a Salmonella effector that inhibits the host's inflammatory responses. The mechanism by which AvrA modulates host cell signaling is not entirely clear. p53 is situated at the crossroads of a network of signaling pathways that are essential for genotoxic and nongenotoxic stress responses. We hypothesized that Salmonella infection activates the p53 pathway. We demonstrated that Salmonella infection increased p53 acetylation. Cells infected with AvrA-sufficient Salmonella have increased p53 acetylation, whereas cells infected with AvrA-deficient Salmonella have less p53 acetylation. In a cell-free system, AvrA possessed acetyltransferase activity and used p53 as a substrate. AvrA expression increased p53 transcriptional activity and induced cell cycle arrest. HCT116 p53-/- cells had less inflammatory responses. In a mouse model of Salmonella infection, intestinal epithelial p53 acetylation was increased by AvrA expression. Our studies provide novel mechanistic evidence that Salmonella modulates the p53 pathway during intestinal inflammation and infection.

  15. Protective Role of Cross-Reactive CD8 T Cells Against Dengue Virus Infection

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    Annie Elong Ngono

    2016-11-01

    Full Text Available Infection with one of the four dengue virus serotypes (DENV1-4 presumably leads to lifelong immunity against the infecting serotype but not against heterotypic reinfection, resulting in a greater risk of developing Dengue Hemorrhagic Fever/Dengue Shock Syndrome (DHF/DSS during secondary infection. Both antibodies and T cell responses have been implicated in DHF/DSS pathogenesis. According to the T cell-based hypothesis termed “original antigenic sin,” secondary DENV infection is dominated by non-protective, cross-reactive T cells that elicit an aberrant immune response. The goal of our study was to compare the roles of serotype-specific and cross-reactive T cells in protection vs. pathogenesis during DENV infection in vivo. Specifically, we utilized IFN-α/βR−/− HLA*B0702 transgenic mice in the context of peptide vaccination with relevant human CD8 T cell epitopes. IFN-α/βR−/− HLA*B0702 transgenic mice were immunized with DENV serotype 2 (DENV2-specific epitopes or variants found in any of the other three serotypes (DENV1, DENV3 or DENV4, followed by challenge with DENV. Although cross-reactive T cell responses were lower than responses elicited by serotype-specific T cells, immunization with either serotype-specific or variant peptide epitopes enhanced viral clearance, demonstrating that both serotype-specific and cross-reactive T cells can contribute to protection in vivo against DENV infection.

  16. Protective Role of Cross-Reactive CD8 T Cells Against Dengue Virus Infection.

    Science.gov (United States)

    Elong Ngono, Annie; Chen, Hui-Wen; Tang, William W; Joo, Yunichel; King, Kevin; Weiskopf, Daniela; Sidney, John; Sette, Alessandro; Shresta, Sujan

    2016-11-01

    Infection with one of the four dengue virus serotypes (DENV1-4) presumably leads to lifelong immunity against the infecting serotype but not against heterotypic reinfection, resulting in a greater risk of developing Dengue Hemorrhagic Fever/Dengue Shock Syndrome (DHF/DSS) during secondary infection. Both antibodies and T cell responses have been implicated in DHF/DSS pathogenesis. According to the T cell-based hypothesis termed "original antigenic sin," secondary DENV infection is dominated by non-protective, cross-reactive T cells that elicit an aberrant immune response. The goal of our study was to compare the roles of serotype-specific and cross-reactive T cells in protection vs. pathogenesis during DENV infection in vivo. Specifically, we utilized IFN-α/βR(-/-) HLA*B0702 transgenic mice in the context of peptide vaccination with relevant human CD8 T cell epitopes. IFN-α/βR(-/-) HLA*B0702 transgenic mice were immunized with DENV serotype 2 (DENV2)-specific epitopes or variants found in any of the other three serotypes (DENV1, DENV3 or DENV4), followed by challenge with DENV. Although cross-reactive T cell responses were lower than responses elicited by serotype-specific T cells, immunization with either serotype-specific or variant peptide epitopes enhanced viral clearance, demonstrating that both serotype-specific and cross-reactive T cells can contribute to protection in vivo against DENV infection.

  17. The impact of inflammation and immune activation on B cell differentiation during HIV-1 infection

    Directory of Open Access Journals (Sweden)

    Nicolas eRuffin

    2012-01-01

    Full Text Available HIV-1 infection is characterized by continuous antigenic stimulation, chronic immune activation and impaired survival of T and B cells. A decline of resting memory B cells has previously been reported to occur in both children and adults infected with HIV-1; these cells are responsible for mounting and maintaining an adequate serological response to antigens previously encountered in life through natural infection or vaccination. Further understanding of the mechanisms leading to impaired B cell differentiation and germinal center reaction might be essential to design new HIV vaccines and therapies that could improve humoral immune responses in HIV-1 infected individuals. In the present article we summarize the literature and present our view on critical mechanisms of B cell development which are impaired during HIV-1 infection. We also discuss the impact of microbial translocation, a driving force for persistent inflammation during HIV-1 infection, on survival of terminally differentiated B cells and how the altered expression of cytokines/chemokines pivotal for communication between T and B cells in lymphoid tissues may impair formation of memory B cells.

  18. Cell culture and animal infection with distinct Trypanosoma cruzi strains expressing red and green fluorescent proteins.

    Science.gov (United States)

    Pires, S F; DaRocha, W D; Freitas, J M; Oliveira, L A; Kitten, G T; Machado, C R; Pena, S D J; Chiari, E; Macedo, A M; Teixeira, S M R

    2008-03-01

    Different strains of Trypanosoma cruzi were transfected with an expression vector that allows the integration of green fluorescent protein (GFP) and red fluorescent protein (RFP) genes into the beta-tubulin locus by homologous recombination. The sites of integration of the GFP and RFP markers were determined by pulse-field gel electrophoresis and Southern blot analyses. Cloned cell lines selected from transfected epimastigote populations maintained high levels of fluorescent protein expression even after 6 months of in vitro culture of epimastigotes in the absence of drug selection. Fluorescent trypomastigotes and amastigotes were observed within Vero cells in culture as well as in hearts and diaphragms of infected mice. The infectivity of the GFP- and RFP-expressing parasites in tissue culture cells was comparable to wild type populations. Furthermore, GFP- and RFP-expressing parasites were able to produce similar levels of parasitemia in mice compared with wild type parasites. Cell cultures infected simultaneously with two cloned cell lines from the same parasite strain, each one expressing a distinct fluorescent marker, showed that at least two different parasites are able to infect the same cell. Double-infected cells were also detected when GFP- and RFP-expressing parasites were derived from strains belonging to two distinct T. cruzi lineages. These results show the usefulness of parasites expressing GFP and RFP for the study of various aspects of T. cruzi infection including the mechanisms of cell invasion, genetic exchange among parasites and the differential tissue distribution in animal models of Chagas disease.

  19. Transforming Growth Factor-β Expression Induced by Rhinovirus Infection in Respiratory Epithelial Cells

    Institute of Scientific and Technical Information of China (English)

    Amrita DOSANJH

    2006-01-01

    Rhinovirus infection of the lower airways is now a recognized disease, associated with bronchiolitis and asthma. The bronchial epithelial cells are the host cells when rhinovirus infection occurs in the airway. It was hypothesized that a pro-fibrotic growth factor response may occur in these infected cells,leading to production of a key transforming growth factor, TGF-β-1. Bronchial epithelial cells were inoculated with human rhinovirus and compared at day 1, 3 and 5 to control non-infected cells. Cell culture supernatant fluid and cellular RNA were isolated. The amount of released TGF-β protein was measured by enzyme-linked immunosorbent assay (ELISA). Expression of TGF-β at the level of transcription was measured by polymerase chain reaction (PCR) and gel electrophoresis. The results show that at all time points studied, TGF-β production is greater in the infected cells, as demonstrated by ELISA (P<0.05) and by semiquantitative PCR analysis. It was concluded that bronchial epithelial cells infected with common cold virus and rhinovirus, showed higher levels of TGF-β. The production of TGF-β may be indicative of a normal repair mechanism to counter inflammation, or in the setting of persistent asthma, could potentially lead to increased fibrosis and collagen deposition.

  20. The role of natural killer cells in the early period of infection in murine cutaneous leishmaniasis

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    M.D. Laurenti

    1999-03-01

    Full Text Available In order to study the role of natural killer (NK cells during the early period of Leishmania infection, BALB/c mice were selectively and permanently depleted of NK cells by injection with 90Sr and subsequently infected with Leishmania (Leishmania amazonensis (HSJD-1 strain. 90Sr is known to selectively deplete NK cells, leaving an intact T- and B-cell compartment and preserving the ability to produce both interferon alpha and IL-2. This method of depletion has advantages when compared with depletion using anti-NK cell monoclonal antibodies because the effect is permanent and neither activates complement nor provokes massive cell death. In the present study, after one month of treatment with 90Sr, the depletion of NK cells was shown by a more than ten-fold reduction in the cytotoxic activity of these cells: 2 x 106 spleen cells from NK-depleted animals were required to reach the same specific lysis of target cells effected by 0.15 x 106 spleen cells from normal control animals. The histopathology of the skin lesion at 7 days after Leishmania infection showed more parasites in the NK cell-depleted group. This observation further strengthens a direct role of NK cells during the early period of Leishmania infection.

  1. Severe cutaneous human papilloma virus infection associated with Natural Killer cell deficiency following stem cell transplantation for severe combined immunodeficiency

    Science.gov (United States)

    Kamili, Qurat-ul-Ain; Seeborg, Filiz O; Saxena, Kapil; Nicholas, Sarah K; Banerjee, Pinaki P; Angelo, Laura S; Mace, Emily M; Forbes, Lisa R; Martinez, Caridad; Wright, Teresa S; Orange, Jordan S.; Hanson, Imelda Celine

    2016-01-01

    Capsule Summary The authors identify Natural Killer cell deficiency in post-transplant severe combined immunodeficiency patients who developed severe human papilloma virus infections as a long term complication. PMID:25159470

  2. Mechanisms of cell death in canine parvovirus-infected cells provide intuitive insights to developing nanotools for medicine.

    Science.gov (United States)

    Nykky, Jonna; Tuusa, Jenni E; Kirjavainen, Sanna; Vuento, Matti; Gilbert, Leona

    2010-08-09

    Viruses have great potential as nanotools in medicine for gene transfer, targeted gene delivery, and oncolytic cancer virotherapy. Here we have studied cell death mechanisms of canine parvovirus (CPV) to increase the knowledge on the CPV life cycle in order to facilitate the development of better parvovirus vectors. Morphological studies of CPV-infected Norden laboratory feline kidney (NLFK) cells and canine fibroma cells (A72) displayed characteristic apoptotic events. Apoptosis was further confirmed by activation of caspases and cellular DNA damage. However, results from annexin V-propidium iodide (PI) labeling and membrane polarization assays indicated disruption of the plasma membrane uncommon to apoptosis. These results provide evidence that secondary necrosis followed apoptosis. In addition, two human cancer cell lines were found to be infected by CPV. This necrotic event over apoptotic cell death and infection in human cells provide insightful information when developing CPV as a nanotool for cancer treatments.

  3. Differentiation-Dependent KLF4 Expression Promotes Lytic Epstein-Barr Virus Infection in Epithelial Cells.

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    Dhananjay M Nawandar

    2015-10-01

    Full Text Available Epstein-Barr virus (EBV is a human herpesvirus associated with B-cell and epithelial cell malignancies. EBV lytically infects normal differentiated oral epithelial cells, where it causes a tongue lesion known as oral hairy leukoplakia (OHL in immunosuppressed patients. However, the cellular mechanism(s that enable EBV to establish exclusively lytic infection in normal differentiated oral epithelial cells are not currently understood. Here we show that a cellular transcription factor known to promote epithelial cell differentiation, KLF4, induces differentiation-dependent lytic EBV infection by binding to and activating the two EBV immediate-early gene (BZLF1 and BRLF1 promoters. We demonstrate that latently EBV-infected, telomerase-immortalized normal oral keratinocyte (NOKs cells undergo lytic viral reactivation confined to the more differentiated cell layers in organotypic raft culture. Furthermore, we show that endogenous KLF4 expression is required for efficient lytic viral reactivation in response to phorbol ester and sodium butyrate treatment in several different EBV-infected epithelial cell lines, and that the combination of KLF4 and another differentiation-dependent cellular transcription factor, BLIMP1, is highly synergistic for inducing lytic EBV infection. We confirm that both KLF4 and BLIMP1 are expressed in differentiated, but not undifferentiated, epithelial cells in normal tongue tissue, and show that KLF4 and BLIMP1 are both expressed in a patient-derived OHL lesion. In contrast, KLF4 protein is not detectably expressed in B cells, where EBV normally enters latent infection, although KLF4 over-expression is sufficient to induce lytic EBV reactivation in Burkitt lymphoma cells. Thus, KLF4, together with BLIMP1, plays a critical role in mediating lytic EBV reactivation in epithelial cells.

  4. HIV infection of naturally occurring and genetically reprogrammed human regulatory T-cells.

    Science.gov (United States)

    Oswald-Richter, Kyra; Grill, Stacy M; Shariat, Nikki; Leelawong, Mindy; Sundrud, Mark S; Haas, David W; Unutmaz, Derya

    2004-07-01

    A T-cell subset, defined as CD4(+)CD25(hi) (regulatory T-cells [Treg cells]), was recently shown to suppress T-cell activation. We demonstrate that human Treg cells isolated from healthy donors express the HIV-coreceptor CCR5 and are highly susceptible to HIV infection and replication. Because Treg cells are present in very few numbers and are difficult to expand in vitro, we genetically modified conventional human T-cells to generate Treg cells in vitro by ectopic expression of FoxP3, a transcription factor associated with reprogramming T-cells into a Treg subset. Overexpression of FoxP3 in naïve human CD4(+) T-cells recapitulated the hyporesponsiveness and suppressive function of naturally occurring Treg cells. However, FoxP3 was less efficient in reprogramming memory T-cell subset into regulatory cells. In addition, FoxP3-transduced T-cells also became more susceptible to HIV infection. Remarkably, a portion of HIV-positive individuals with a low percentage of CD4(+) and higher levels of activated T-cells have greatly reduced levels of FoxP3(+)CD4(+)CD25(hi) T-cells, suggesting disruption of the Treg cells during HIV infection. Targeting and disruption of the T-cell regulatory system by HIV may contribute to hyperactivation of conventional T-cells, a characteristic of HIV disease progression. Moreover, the ability to reprogram human T-cells into Treg cells in vitro will greatly aid in decoding their mechanism of suppression, their enhanced susceptibility to HIV infection, and the unique markers expressed by this subset.

  5. HIV infection of naturally occurring and genetically reprogrammed human regulatory T-cells.

    Directory of Open Access Journals (Sweden)

    Kyra Oswald-Richter

    2004-07-01

    Full Text Available A T-cell subset, defined as CD4(+CD25(hi (regulatory T-cells [Treg cells], was recently shown to suppress T-cell activation. We demonstrate that human Treg cells isolated from healthy donors express the HIV-coreceptor CCR5 and are highly susceptible to HIV infection and replication. Because Treg cells are present in very few numbers and are difficult to expand in vitro, we genetically modified conventional human T-cells to generate Treg cells in vitro by ectopic expression of FoxP3, a transcription factor associated with reprogramming T-cells into a Treg subset. Overexpression of FoxP3 in naïve human CD4(+ T-cells recapitulated the hyporesponsiveness and suppressive function of naturally occurring Treg cells. However, FoxP3 was less efficient in reprogramming memory T-cell subset into regulatory cells. In addition, FoxP3-transduced T-cells also became more susceptible to HIV infection. Remarkably, a portion of HIV-positive individuals with a low percentage of CD4(+ and higher levels of activated T-cells have greatly reduced levels of FoxP3(+CD4(+CD25(hi T-cells, suggesting disruption of the Treg cells during HIV infection. Targeting and disruption of the T-cell regulatory system by HIV may contribute to hyperactivation of conventional T-cells, a characteristic of HIV disease progression. Moreover, the ability to reprogram human T-cells into Treg cells in vitro will greatly aid in decoding their mechanism of suppression, their enhanced susceptibility to HIV infection, and the unique markers expressed by this subset.

  6. CD8 T cells are essential for recovery from a respiratory vaccinia virus infection.

    Science.gov (United States)

    Goulding, John; Bogue, Rebecka; Tahiliani, Vikas; Croft, Michael; Salek-Ardakani, Shahram

    2012-09-01

    The precise immune components required for protection against a respiratory Orthopoxvirus infection, such as human smallpox or monkeypox, remain to be fully identified. In this study, we used the virulent Western Reserve strain of vaccinia virus (VACV-WR) to model a primary respiratory Orthopoxvirus infection. Naive mice infected with VACV-WR mounted an early CD8 T cell response directed against dominant and subdominant VACV-WR Ags, followed by a CD4 T cell and Ig response. In contrast to other VACV-WR infection models that highlight the critical requirement for CD4 T cells and Ig, we found that only mice deficient in CD8 T cells presented with severe cachexia, pulmonary inflammation, viral dissemination, and 100% mortality. Depletion of CD8 T cells at specified times throughout infection highlighted that they perform their critical function between days 4 and 6 postinfection and that their protective requirement is critically dictated by initial viral load and virulence. Finally, the ability of adoptively transferred naive CD8 T cells to protect RAG⁻/⁻ mice against a lethal VACV-WR infection demonstrated that they are both necessary and sufficient in protecting against a primary VACV-WR infection of the respiratory tract.

  7. Cell Culture Models for the Investigation of Hepatitis B and D Virus Infection

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    Eloi R. Verrier

    2016-09-01

    Full Text Available Chronic hepatitis B virus (HBV and hepatitis D virus (HDV infections are major causes of liver disease and hepatocellular carcinoma worldwide. Despite the presence of an efficient preventive vaccine, more than 250 million patients are chronically infected with HBV. Current antivirals effectively control but only rarely cure chronic infection. While the molecular biology of the two viruses has been characterized in great detail, the absence of robust cell culture models for HBV and/or HDV infection has limited the investigation of virus-host interactions. Native hepatoma cell lines do not allow viral infection, and the culture of primary hepatocytes, the natural host cell for the viruses, implies a series of constraints restricting the possibilities of analyzing virus-host interactions. Recently, the discovery of the sodium taurocholate co-transporting polypeptide (NTCP as a key HBV/HDV cell entry factor has opened the door to a new era of investigation, as NTCP-overexpressing hepatoma cells acquire susceptibility to HBV and HDV infections. In this review, we summarize the major cell culture models for HBV and HDV infection, discuss their advantages and limitations and highlight perspectives for future developments.

  8. Cell Culture Models for the Investigation of Hepatitis B and D Virus Infection

    Science.gov (United States)

    Verrier, Eloi R.; Colpitts, Che C.; Schuster, Catherine; Zeisel, Mirjam B.; Baumert, Thomas F.

    2016-01-01

    Chronic hepatitis B virus (HBV) and hepatitis D virus (HDV) infections are major causes of liver disease and hepatocellular carcinoma worldwide. Despite the presence of an efficient preventive vaccine, more than 250 million patients are chronically infected with HBV. Current antivirals effectively control but only rarely cure chronic infection. While the molecular biology of the two viruses has been characterized in great detail, the absence of robust cell culture models for HBV and/or HDV infection has limited the investigation of virus-host interactions. Native hepatoma cell lines do not allow viral infection, and the culture of primary hepatocytes, the natural host cell for the viruses, implies a series of constraints restricting the possibilities of analyzing virus-host interactions. Recently, the discovery of the sodium taurocholate co-transporting polypeptide (NTCP) as a key HBV/HDV cell entry factor has opened the door to a new era of investigation, as NTCP-overexpressing hepatoma cells acquire susceptibility to HBV and HDV infections. In this review, we summarize the major cell culture models for HBV and HDV infection, discuss their advantages and limitations and highlight perspectives for future developments. PMID:27657111

  9. Primary macrophages and J774 cells respond differently to infection with Mycobacterium tuberculosis

    Science.gov (United States)

    Andreu, Nuria; Phelan, Jody; de Sessions, Paola F.; Cliff, Jacqueline M.; Clark, Taane G.; Hibberd, Martin L.

    2017-01-01

    Macrophages play an essential role in the early immune response to Mycobacterium tuberculosis and are the cell type preferentially infected in vivo. Primary macrophages and macrophage-like cell lines are commonly used as infection models, although the physiological relevance of cell lines, particularly for host-pathogen interaction studies, is debatable. Here we use high-throughput RNA-sequencing to analyse transcriptome dynamics of two macrophage models in response to M. tuberculosis infection. Specifically, we study the early response of bone marrow-derived mouse macrophages and cell line J774 to infection with live and γ-irradiated (killed) M. tuberculosis. We show that infection with live bacilli specifically alters the expression of host genes such as Rsad2, Ifit1/2/3 and Rig-I, whose potential roles in resistance to M. tuberculosis infection have not yet been investigated. In addition, the response of primary macrophages is faster and more intense than that of J774 cells in terms of number of differentially expressed genes and magnitude of induction/repression. Our results point to potentially novel processes leading to immune containment early during M. tuberculosis infection, and support the idea that important differences exist between primary macrophages and cell lines, which should be taken into account when choosing a macrophage model to study host-pathogen interactions. PMID:28176867

  10. Permissive human cytomegalovirus infection of a first trimester extravillous cytotrophoblast cell line

    Directory of Open Access Journals (Sweden)

    LaMarca Heather L

    2004-11-01

    Full Text Available Abstract Human cytomegalovirus (HCMV is the leading cause of congenital viral infection in the United States and Europe. Despite the significant morbidity associated with prenatal HCMV infection, little is known about how the virus infects the fetus during pregnancy. To date, primary human cytotrophoblasts (CTBs have been utilized to study placental HCMV infection and replication; however, the minimal mitotic potential of these cells restricts experimentation to a few days, which may be problematic for mechanistic studies of the slow-replicating virus. The aim of this study was to determine whether the human first trimester CTB cell line SGHPL-4 was permissive for HCMV infection and therefore could overcome such limitations. HCMV immediate early (IE protein expression was detected as early as 3 hours post-infection in SGHPL-4 cells and progressively increased as a function of time. HCMV growth assays revealed the presence of infectious virus in both cell lysates and culture supernatants, indicating that viral replication and the release of progeny virus occurred. Compared to human fibroblasts, viral replication was delayed in CTBs, consistent with previous studies reporting delayed viral kinetics in HCMV-infected primary CTBs. These results indicate that SGHPL-4 cells are fully permissive for the complete HCMV replicative cycle. Our findings suggest that these cells may serve as useful tools for future mechanistic studies of HCMV pathogenesis during early pregnancy.

  11. Immune response in virus model structured by cell infection-age.

    Science.gov (United States)

    Browne, Cameron

    2016-10-01

    This paper concerns modeling the coupled within-host population dynamics of virus and CTL (Cytotoxic T Lymphocyte) immune response. There is substantial evidence that the CTL immune response plays a crucial role in controlling HIV in infected patients. Recent experimental studies have demonstrated that certain CTL variants can recognize HIV infected cells early in the infected cell lifecycle before viral production, while other CTLs only detect viral proteins (epitopes) presented on the surface of infected cells after viral production. The kinetics of epitope presentation and immune recognition can impact the efficacy of the immune response. We extend previous virus models to include cell infection-age structure in the infected cell compartment and immune response killing/activation rates of a PDE-ODE system. We characterize solutions to our system utilizing semigroup theory, determine equilibria and reproduction numbers, and prove stability and persistence results. Numerical simulations show that ' early immune recognition' precipitates both enhanced viral control and sustained oscillations via a Hopf bifurcation. In addition to inducing oscillatory dynamics, considering immune process rates to be functions of cell infection-age can also lead to coexistence of multiple distinct immune effector populations.

  12. Iridovirus infection of cell cultures from the Diaprepes root weevil, Diaprepes abbreviatus

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    W.B. Hunter

    2003-12-01

    Full Text Available We here report the development and viral infection of a Diaprepes root weevil cell culture. Embryonic tissues of the root weevil were used to establish cell cultures for use in screening viral pathogens as potential biological control agents. Tissues were seeded into a prepared solution of insect medium and kept at a temperature of 24°C. The cell culture had primarily fibroblast-like morphology with some epithelial monolayers. Root weevil cells were successfully infected in vitro with a known insect virus, Invertebrate Iridescent Virus 6. Potential uses of insect cell cultures and insect viruses are discussed.

  13. Short Communication: Preferential Killing of HIV Latently Infected CD4+ T Cells by MALT1 Inhibitor

    Science.gov (United States)

    Li, Hongmei; He, Hui; Gong, Leyi; Fu, Mingui

    2016-01-01

    Abstract We report that the addition of an host paracaspase MALT1 inhibitor, MI-2, to HIV latently infected ACH-2, Jurkat E4, and J-LAT cells accelerated cell death in the presence of cell stimuli or the protein kinase C agonist, bryostatin 1. MI-2-mediated cell death correlated with the induction of the cellular RNase MCPIP1 and requires the presence of viral component(s). Altogether, the combination of MI-2 and bryostatin 1 displays selective killing of HIV latently infected CD4+ T cells. PMID:26728103

  14. Short Communication: Preferential Killing of HIV Latently Infected CD4(+) T Cells by MALT1 Inhibitor.

    Science.gov (United States)

    Li, Hongmei; He, Hui; Gong, Leyi; Fu, Mingui; Wang, Tony T

    2016-02-01

    We report that the addition of an host paracaspase MALT1 inhibitor, MI-2, to HIV latently infected ACH-2, Jurkat E4, and J-LAT cells accelerated cell death in the presence of cell stimuli or the protein kinase C agonist, bryostatin 1. MI-2-mediated cell death correlated with the induction of the cellular RNase MCPIP1 and requires the presence of viral component(s). Altogether, the combination of MI-2 and bryostatin 1 displays selective killing of HIV latently infected CD4(+) T cells.

  15. Murine and bovine γδ T cells enhance innate immunity against Brucella abortus infections.

    Directory of Open Access Journals (Sweden)

    Jerod A Skyberg

    Full Text Available γδ T cells have been postulated to act as a first line of defense against infectious agents, particularly intracellular pathogens, representing an important link between the innate and adaptive immune responses. Human γδ T cells expand in the blood of brucellosis patients and are active against Brucella in vitro. However, the role of γδ T cells in vivo during experimental brucellosis has not been studied. Here we report TCRδ(-/- mice are more susceptible to B. abortus infection than C57BL/6 mice at one week post-infection as measured by splenic colonization and splenomegaly. An increase in TCRγδ cells was observed in the spleens of B. abortus-infected C57BL/6 mice, which peaked at two weeks post-infection and occurred concomitantly with diminished brucellae. γδ T cells were the major source of IL-17 following infection and also produced IFN-γ. Depletion of γδ T cells from C57BL/6, IL-17Rα(-/-, and GMCSF(-/- mice enhanced susceptibility to B. abortus infection although this susceptibility was unaltered in the mutant mice; however, when γδ T cells were depleted from IFN-γ(-/- mice, enhanced susceptibility was observed. Neutralization of γδ T cells in the absence of TNF-α did not further impair immunity. In the absence of TNF-α or γδ T cells, B. abortus-infected mice showed enhanced IFN-γ, suggesting that they augmented production to compensate for the loss of γδ T cells and/or TNF-α. While the protective role of γδ T cells was TNF-α-dependent, γδ T cells were not the major source of TNF-α and activation of γδ T cells following B. abortus infection was TNF-α-independent. Additionally, bovine TCRγδ cells were found to respond rapidly to B. abortus infection upon co-culture with autologous macrophages and could impair the intramacrophage replication of B. abortus via IFN-γ. Collectively, these results demonstrate γδ T cells are important for early protection to B. abortus infections.

  16. Helicobacter pylori Infection Induces Genetic Instability of Nuclear and Mitochondrial DNA in Gastric Cells

    DEFF Research Database (Denmark)

    Machado, Ana Manuel; Figueiredo, Ceu; Touati, Eliette;

    2009-01-01

    Purpose: Helicobacter pylori is a major cause of gastric carcinoma. To investigate a possible link between bacterial infection and genetic instability of the host genome, we examined the effect of H. pylori infection on known cellular repair pathways in vitro and in vivo. Moreover, various types...... of genetic instabilities in the nuclear and mitochondrial DNA (mtDNA) were examined. Experimental Design: We observed the effects of H pylori infection on a gastric cell line (AGS), on C57BL/6 mice, and on individuals with chronic gastritis. In AGS cells, the effect of H pylori infection on base excision...... cells and chronic gastritis tissue were determined by PCR, single-stranded conformation polymorphism, and sequencing. H pylori vacA and cagA genotyping was determined by multiplex PCR and reverse hybridization. Results: Following H pylori infection, the activity and expression of base excision repair...

  17. HIV infection induces morphometrical changes on the oral (buccal mucosa and tongue) epithelial cells.

    Science.gov (United States)

    Pompermayer, Adriane Bastos; Gil, Francisca Berenice Dias; França, Beatriz Helena Sottile; Machado, Maria Ângela Naval; Trevilatto, Paula Cristina; Fernandes, Angela; de Lima, Antônio Adilson Soares

    2011-01-01

    The aim of this study was to assess morphological and morphometrical alterations of oral squamous epithelial cells in type 1 HIV infected individuals. Oral smears were collected from tongue and buccal mucosa of 30 HIV infected (experimental) and 30 non-infected (control) individuals by liquid-based exfoliative cytology. The cells were morphologically analyzed and the nuclear area (NA), the cytoplasmic area (CA) and the nucleus-to-cytoplasm area ratio (NA/CA) were calculated. No morphological differences were found between the groups. The mean values of CA were decreased in tongue (P=.00006) and buccal mucosa (P=.00242) in HIV infected individual, while mean values of NA were increased (P=.00308 and .00095, respectively) in the same group. NA/CA ratio for experimental group was increased in both collected places, with P=.00001 (tongue) and P=.00000 (buccal mucosa). This study revealed that HIV infection was able to induce morphometrical changes on the oral epithelial cells.

  18. T Cell Factor 1-Expressing Memory-like CD8(+) T Cells Sustain the Immune Response to Chronic Viral Infections.

    Science.gov (United States)

    Utzschneider, Daniel T; Charmoy, Mélanie; Chennupati, Vijaykumar; Pousse, Laurène; Ferreira, Daniela Pais; Calderon-Copete, Sandra; Danilo, Maxime; Alfei, Francesca; Hofmann, Maike; Wieland, Dominik; Pradervand, Sylvain; Thimme, Robert; Zehn, Dietmar; Held, Werner

    2016-08-16

    Chronic infections promote the terminal differentiation (or "exhaustion") of T cells and are thought to preclude the formation of memory T cells. In contrast, we discovered a small subpopulation of virus-specific CD8(+) T cells that sustained the T cell response during chronic infections. These cells were defined by, and depended on, the expression of the transcription factor Tcf1. Transcriptome analysis revealed that this population shared key characteristics of central memory cells but lacked an effector signature. Unlike conventional memory cells, Tcf1-expressing T cells displayed hallmarks of an "exhausted" phenotype, including the expression of inhibitory receptors such as PD-1 and Lag-3. This population was crucial for the T cell expansion that occurred in response to inhibitory receptor blockade during chronic infection. These findings identify a memory-like T cell population that sustains T cell responses and is a prime target for therapeutic interventions to improve the immune response in chronic infections. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Imbalance of placental regulatory T cell and Th17 cell population dynamics in the FIV-infected pregnant cat

    Directory of Open Access Journals (Sweden)

    Boudreaux Crystal E

    2012-05-01

    Full Text Available Abstract Background An appropriate balance in placental regulatory T cells (Tregs, an immunosuppressive cell population, and Th17 cells, a pro-inflammatory cell population, is essential in allowing tolerance of the semi-allogeneic fetus. TGF-β and IL-6 are cytokines that promote differentiation of Tregs and Th17 cells from a common progenitor; aberrant expression of the cytokines may perturb the balance in the two cell populations. We previously reported a pro-inflammatory placental environment with decreased levels of FoxP3, a Treg marker, and increased levels of IL-6 in the placentas of FIV-infected cats at early pregnancy. Thus, we hypothesized that FIV infection in the pregnant cat causes altered placental Treg and Th17 cell populations, possibly resulting in placental inflammation. Methods We examined the effect of FIV infection on Treg and Th17 populations in placentas at early pregnancy using quantitative confocal microscopy to measure FoxP3 or RORγ, a Th17 marker, and qPCR to quantify expression of the key cytokines TGF-β and IL-6. Results FoxP3 and RORγ were positively correlated in FIV-infected placentas at early pregnancy, but not placentas from normal cats, indicating virus-induced alteration in the balance of these cell populations. In control cats the expression of IL-6 and RORγ was positively correlated as predicted, but this relationship was disrupted in infected animals. TGF-β was reduced in infected queens, an occurrence that could dysregulate both Treg and Th17 cell populations. Co-expression analyses revealed a highly significant positive correlation between IL-6 and TGF-β expression in control animals that did not occur in infected animals. Conclusion Collectively, these data point toward potential disruption in the balance of Treg and Th17 cell populations that may contribute to FIV-induced inflammation in the feline placenta.

  20. Infections after allogeneic hematopoietic stem cell transplantation with a nonmyeloablative conditioning regimen.

    OpenAIRE

    Frere, Pascale; Baron, Frédéric; Bonnet, Christophe; HAFRAOUI, Kaoutar; Pereira-Martins, Maguy; Willems, Evelyne; Fillet, Georges; Beguin, Yves

    2006-01-01

    Hematopoietic cell transplantation (HCT) following nonmyeloablative conditioning (NMSCT) may be associated with a reduced risk of infection compared to standard allogeneic HCT. We retrospectively analyzed incidence and risk factors of infection in 62 patients undergoing NMSCT with low-dose TBI +/- fludarabine and postgrafting CsA and MMF. The proportion of patients with any infection was 77%, but the majority of infectious events occurred beyond day 30. Donor other than sibling, older age, ea...

  1. The Influence of Programmed Cell Death in Myeloid Cells on Host Resilience to Infection with Legionella pneumophila or Streptococcus pyogenes

    Science.gov (United States)

    Gamradt, Pia; Xu, Yun; Gratz, Nina; Duncan, Kellyanne; Kobzik, Lester; Högler, Sandra; Decker, Thomas

    2016-01-01

    Pathogen clearance and host resilience/tolerance to infection are both important factors in surviving an infection. Cells of the myeloid lineage play important roles in both of these processes. Neutrophils, monocytes, macrophages, and dendritic cells all have important roles in initiation of the immune response and clearance of bacterial pathogens. If these cells are not properly regulated they can result in excessive inflammation and immunopathology leading to decreased host resilience. Programmed cell death (PCD) is one possible mechanism that myeloid cells may use to prevent excessive inflammation. Myeloid cell subsets play roles in tissue repair, immune response resolution, and maintenance of homeostasis, so excessive PCD may also influence host resilience in this way. In addition, myeloid cell death is one mechanism used to control pathogen replication and dissemination. Many of these functions for PCD have been well defined in vitro, but the role in vivo is less well understood. We created a mouse that constitutively expresses the pro-survival B-cell lymphoma (bcl)-2 protein in myeloid cells (CD68(bcl2tg), thus decreasing PCD specifically in myeloid cells. Using this mouse model we explored the impact that decreased cell death of these cells has on infection with two different bacterial pathogens, Legionella pneumophila and Streptococcus pyogenes. Both of these pathogens target multiple cell death pathways in myeloid cells, and the expression of bcl2 resulted in decreased PCD after infection. We examined both pathogen clearance and host resilience and found that myeloid cell death was crucial for host resilience. Surprisingly, the decreased myeloid PCD had minimal impact on pathogen clearance. These data indicate that the most important role of PCD during infection with these bacteria is to minimize inflammation and increase host resilience, not to aid in the clearance or prevent the spread of the pathogen. PMID:27973535

  2. Infections

    Science.gov (United States)

    ... Does My Child Need? How to Safely Give Acetaminophen Is It a Cold or the Flu? Is the Flu Vaccine a Good Idea for Your Family? Too Late for the Flu Vaccine? Common Childhood Infections Can Chronic Ear Infections Cause Long-Term Hearing Loss? Chickenpox Cold Sores Common Cold Diarrhea Fever and ...

  3. Therapeutic doses of irradiation activate viral transcription and induce apoptosis in HIV-1 infected cells

    Energy Technology Data Exchange (ETDEWEB)

    Iordanskiy, Sergey [School of Systems Biology, Laboratory of Molecular Virology, George Mason University, Manassas, VA 20110 (United States); Van Duyne, Rachel [School of Systems Biology, Laboratory of Molecular Virology, George Mason University, Manassas, VA 20110 (United States); Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702 (United States); Sampey, Gavin C; Woodson, Caitlin M; Fry, Kelsi; Saifuddin, Mohammed; Guo, Jia; Wu, Yuntao [School of Systems Biology, Laboratory of Molecular Virology, George Mason University, Manassas, VA 20110 (United States); Romerio, Fabio [Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201 (United States); Kashanchi, Fatah, E-mail: fkashanc@gmu.edu [School of Systems Biology, Laboratory of Molecular Virology, George Mason University, Manassas, VA 20110 (United States)

    2015-11-15

    The highly active antiretroviral therapy reduces HIV-1 RNA in plasma to undetectable levels. However, the virus continues to persist in the long-lived resting CD4{sup +} T cells, macrophages and astrocytes which form a viral reservoir in infected individuals. Reactivation of viral transcription is critical since the host immune response in combination with antiretroviral therapy may eradicate the virus. Using the chronically HIV-1 infected T lymphoblastoid and monocytic cell lines, primary quiescent CD4{sup +} T cells and humanized mice infected with dual-tropic HIV-1 89.6, we examined the effect of various X-ray irradiation (IR) doses (used for HIV-related lymphoma treatment and lower doses) on HIV-1 transcription and viability of infected cells. Treatment of both T cells and monocytes with IR, a well-defined stress signal, led to increase of HIV-1 transcription, as evidenced by the presence of RNA polymerase II and reduction of HDAC1 and methyl transferase SUV39H1 on the HIV-1 promoter. This correlated with the increased GFP signal and elevated level of intracellular HIV-1 RNA in the IR-treated quiescent CD4{sup +} T cells infected with GFP-encoding HIV-1. Exposition of latently HIV-1infected monocytes treated with PKC agonist bryostatin 1 to IR enhanced transcription activation effect of this latency-reversing agent. Increased HIV-1 replication after IR correlated with higher cell death: the level of phosphorylated Ser46 in p53, responsible for apoptosis induction, was markedly higher in the HIV-1 infected cells following IR treatment. Exposure of HIV-1 infected humanized mice with undetectable viral RNA level to IR resulted in a significant increase of HIV-1 RNA in plasma, lung and brain tissues. Collectively, these data point to the use of low to moderate dose of IR alone or in combination with HIV-1 transcription activators as a potential application for the “Shock and Kill” strategy for latently HIV-1 infected cells. - Highlights: • X-ray irradiation

  4. Barriers to Infection of Human Cells by Feline Leukemia Virus: Insights into Resistance to Zoonosis

    Science.gov (United States)

    Terry, Anne; Kilbey, Anna; Naseer, Asif; Levy, Laura S.; Ahmad, Shamim; Watts, Ciorsdaidh; Mackay, Nancy; Cameron, Ewan; Wilson, Sam

    2016-01-01

    ABSTRACT The human genome displays a rich fossil record of past gammaretrovirus infections, yet no current epidemic is evident, despite environmental exposure to viruses that infect human cells in vitro. Feline leukemia viruses (FeLVs) rank high on this list, but neither domestic nor workplace exposure has been associated with detectable serological responses. Nonspecific inactivation of gammaretroviruses by serum factors appears insufficient to explain these observations. To investigate further, we explored the susceptibilities of primary and established human cell lines to FeLV-B, the most likely zoonotic variant. Fully permissive infection was common in cancer-derived cell lines but was also a feature of nontransformed keratinocytes and lung fibroblasts. Cells of hematopoietic origin were generally less permissive and formed discrete groups on the basis of high or low intracellular protein expression and virion release. Potent repression was observed in primary human blood mononuclear cells and a subset of leukemia cell lines. However, the early steps of reverse transcription and integration appear to be unimpaired in nonpermissive cells. FeLV-B was subject to G→A hypermutation with a predominant APOBEC3G signature in partially permissive cells but was not mutated in permissive cells or in nonpermissive cells that block secondary viral spread. Distinct cellular barriers that protect primary human blood cells are likely to be important in protection against zoonotic infection with FeLV. IMPORTANCE Domestic exposure to gammaretroviruses such as feline leukemia viruses (FeLVs) occurs worldwide, but the basis of human resistance to infection remains incompletely understood. The potential threat is evident from the human genome sequence, which reveals many past epidemics of gammaretrovirus infection, and from recent cross-species jumps of gammaretroviruses from rodents to primates and marsupials. This study examined resistance to infection at the cellular level

  5. Barriers to Infection of Human Cells by Feline Leukemia Virus: Insights into Resistance to Zoonosis.

    Science.gov (United States)

    Terry, Anne; Kilbey, Anna; Naseer, Asif; Levy, Laura S; Ahmad, Shamim; Watts, Ciorsdaidh; Mackay, Nancy; Cameron, Ewan; Wilson, Sam; Neil, James C

    2017-03-01

    The human genome displays a rich fossil record of past gammaretrovirus infections, yet no current epidemic is evident, despite environmental exposure to viruses that infect human cells in vitro Feline leukemia viruses (FeLVs) rank high on this list, but neither domestic nor workplace exposure has been associated with detectable serological responses. Nonspecific inactivation of gammaretroviruses by serum factors appears insufficient to explain these observations. To investigate further, we explored the susceptibilities of primary and established human cell lines to FeLV-B, the most likely zoonotic variant. Fully permissive infection was common in cancer-derived cell lines but was also a feature of nontransformed keratinocytes and lung fibroblasts. Cells of hematopoietic origin were generally less permissive and formed discrete groups on the basis of high or low intracellular protein expression and virion release. Potent repression was observed in primary human blood mononuclear cells and a subset of leukemia cell lines. However, the early steps of reverse transcription and integration appear to be unimpaired in nonpermissive cells. FeLV-B was subject to G→A hypermutation with a predominant APOBEC3G signature in partially permissive cells but was not mutated in permissive cells or in nonpermissive cells that block secondary viral spread. Distinct cellular barriers that protect primary human blood cells are likely to be important in protection against zoonotic infection with FeLV.IMPORTANCE Domestic exposure to gammaretroviruses such as feline leukemia viruses (FeLVs) occurs worldwide, but the basis of human resistance to infection remains incompletely understood. The potential threat is evident from the human genome sequence, which reveals many past epidemics of gammaretrovirus infection, and from recent cross-species jumps of gammaretroviruses from rodents to primates and marsupials. This study examined resistance to infection at the cellular level with the most

  6. Varicella zoster virus infection of human fetal lung cells alters mitochondrial morphology.

    Science.gov (United States)

    Keller, Amy C; Badani, Hussain; McClatchey, P Mason; Baird, Nicholas L; Bowlin, Jacqueline L; Bouchard, Ron; Perng, Guey-Chuen; Reusch, Jane E B; Kaufer, Benedikt B; Gilden, Don; Shahzad, Aamir; Kennedy, Peter G E; Cohrs, Randall J

    2016-10-01

    Varicella zoster virus (VZV) is a ubiquitous alphaherpesvirus that establishes latency in ganglionic neurons throughout the neuraxis after primary infection. Here, we show that VZV infection induces a time-dependent significant change in mitochondrial morphology, an important indicator of cellular health, since mitochondria are involved in essential cellular functions. VZV immediate-early protein 63 (IE63) was detected in mitochondria-rich cellular fractions extracted from infected human fetal lung fibroblasts (HFL) by Western blotting. IE63 interacted with cytochrome c oxidase in bacterial 2-hybrid analyses. Confocal microscopy of VZV-infected HFL cells at multiple times after infection revealed the presence of IE63 in the nucleus, mitochondria, and cytoplasm. Our data provide the first evidence that VZV infection induces alterations in mitochondrial morphology, including fragmentation, which may be involved in cellular damage and/or death during virus infection.

  7. Antigen-specific memory B-cell responses to enterotoxigenic Escherichia coli infection in Bangladeshi adults.

    Science.gov (United States)

    Alam, Mohammad Murshid; Aktar, Amena; Afrin, Sadia; Rahman, Mohammad Arif; Aktar, Sarmin; Uddin, Taher; Rahman, M Arifur; Al Mahbuba, Deena; Chowdhury, Fahima; Khan, Ashraful Islam; Bhuiyan, Taufiqur Rahman; Begum, Yasmin Ara; Ryan, Edward T; Calderwood, Stephen B; Svennerholm, Ann-Mari; Qadri, Firdausi

    2014-04-01

    Multiple infections with diverse enterotoxigenic E. coli (ETEC) strains lead to broad spectrum protection against ETEC diarrhea. However, the precise mechanism of protection against ETEC infection is still unknown. Therefore, memory B cell responses and affinity maturation of antibodies to the specific ETEC antigens might be important to understand the mechanism of protection. In this study, we investigated the heat labile toxin B subunit (LTB) and colonization factor antigens (CFA/I and CS6) specific IgA and IgG memory B cell responses in Bangladeshi adults (n = 52) who were infected with ETEC. We also investigated the avidity of IgA and IgG antibodies that developed after infection to these antigens. Patients infected with ETEC expressing LT or LT+heat stable toxin (ST) and CFA/I group or CS6 colonization factors developed LTB, CFA/I or CS6 specific memory B cell responses at day 30 after infection. Similarly, these patients developed high avidity IgA and IgG antibodies to LTB, CFA/I or CS6 at day 7 that remained significantly elevated at day 30 when compared to the avidity of these specific antibodies at the acute stage of infection (day 2). The memory B cell responses, antibody avidity and other immune responses to CFA/I not only developed in patients infected with ETEC expressing CFA/I but also in those infected with ETEC expressing CFA/I cross-reacting epitopes. We also detected a significant positive correlation of LTB, CFA/I and CS6 specific memory B cell responses with the corresponding increase in antibody avidity. This study demonstrates that natural infection with ETEC induces memory B cells and high avidity antibodies to LTB and colonization factor CFA/I and CS6 antigens that could mediate anamnestic responses on re-exposure to ETEC and may help in understanding the requirements to design an effective vaccination strategies.

  8. The Involvement of Microglial Cells in Japanese Encephalitis Infections

    Science.gov (United States)

    Thongtan, Thananya; Thepparit, Chutima; Smith, Duncan R.

    2012-01-01

    Despite the availability of effective vaccines, Japanese encephalitis virus (JEV) infections remain a leading cause of encephalitis in many Asian countries. The virus is transmitted to humans by Culex mosquitoes, and, while the majority of human infections are asymptomatic, up to 30% of JE cases admitted to hospital die and 50% of the survivors suffer from neurological sequelae. Microglia are brain-resident macrophages that play key roles in both the innate and adaptive immune responses in the CNS and are thus of importance in determining the pathology of encephalitis as a result of JEV infection. PMID:22919405

  9. Compensatory T cell responses in IRG-deficient mice prevent sustained Chlamydia trachomatis infections.

    Directory of Open Access Journals (Sweden)

    Jörn Coers

    2011-06-01

    Full Text Available The obligate intracellular pathogen Chlamydia trachomatis is the most common cause of bacterial sexually transmitted diseases in the United States. In women C. trachomatis can establish persistent genital infections that lead to pelvic inflammatory disease and sterility. In contrast to natural infections in humans, experimentally induced infections with C. trachomatis in mice are rapidly cleared. The cytokine interferon-γ (IFNγ plays a critical role in the clearance of C. trachomatis infections in mice. Because IFNγ induces an antimicrobial defense system in mice but not in humans that is composed of a large family of Immunity Related GTPases (IRGs, we questioned whether mice deficient in IRG immunity would develop persistent infections with C. trachomatis as observed in human patients. We found that IRG-deficient Irgm1/m3((-/- mice transiently develop high bacterial burden post intrauterine infection, but subsequently clear the infection more efficiently than wildtype mice. We show that the delayed but highly effective clearance of intrauterine C. trachomatis infections in Irgm1/m3((-/- mice is dependent on an exacerbated CD4(+ T cell response. These findings indicate that the absence of the predominant murine innate effector mechanism restricting C. trachomatis growth inside epithelial cells results in a compensatory adaptive immune response, which is at least in part driven by CD4(+ T cells and prevents the establishment of a persistent infection in mice.

  10. Manipulation of PrPres production in scrapie-infected neuroblastoma cells

    NARCIS (Netherlands)

    Bate, C.; Langeveld, J.P.M.; Williams, A.

    2004-01-01

    In the present study the accumulation of protease resistant prion protein (PrPres) in scrapie-infected neuroblastoma cells (ScN2a cells) was shown to be dependent on culture conditions. The highest levels of PrPres were found in slow growing cells. Further increases in PrPres accumulation were obser

  11. Giant cell arteritis associated with chronic active Epstein-Barr virus infection

    Directory of Open Access Journals (Sweden)

    A. Giardina

    2013-03-01

    Full Text Available Giant cell arteritis is an inflammatory vasculopathy that preferentially affects medium-sized and large arteries. A viral cause has been suspected but not confirmed in polymyalgia rheumatica and giant-cell arteritis. We report the case of a 81-year-old female who suffered from chronic active Epstein-Barr virus infection and developed giant cell temporal arteritis.

  12. Epstein-Barr virus infection in ex vivo tonsil epithelial cell cultures of asymptomatic carriers.

    NARCIS (Netherlands)

    Pegtel, DM; Middeldorp, J.M.; Thorley-Lawson, DA

    2004-01-01

    Epstein-Barr virus (EBV) is found frequently in certain epithelial pathologies, such as nasopharyngeal carcinoma and oral hairy leukoplakia, indicating that the virus can infect epithelial cells in vivo. Recent studies of cell lines imply that epithelial cells may also play a role in persistent EBV

  13. Metabolic effects of influenza virus infection in cultured animal cells: Intra- and extracellular metabolite profiling

    NARCIS (Netherlands)

    Ritter, J.B.; Wahl, A.S.; Freund, S.; Genzel, Y.; Reichl, U.

    2010-01-01

    Background: Many details in cell culture-derived influenza vaccine production are still poorly understood and approaches for process optimization mainly remain empirical. More insights on mammalian cell metabolism after a viral infection could give hints on limitations and cell-specific virus

  14. Viral infection, proliferation, and hyperplasia of Hofbauer cells and absence of inflammation characterize the placental pathology of fetuses with congenital Zika virus infection.

    Science.gov (United States)

    Schwartz, David A

    2017-06-01

    Attention is increasingly focused on the potential mechanism(s) for Zika virus infection to be transmitted from an infected mother to her fetus. This communication addresses current evidence for the role of the placenta in vertical transmission of the Zika virus. Placentas from second and third trimester fetuses with confirmed intrauterine Zika virus infection were examined with routine staining to determine the spectrum of pathologic changes. In addition, immunohistochemical staining for macrophages and nuclear proliferation antigens was performed. Viral localization was identified using RNA hybridization. These observations were combined with the recent published results of placental pathology to increase the strength of the pathology data. Results were correlated with published data from experimental studies of Zika virus infection in placental cells and chorionic villous explants. Placentas from fetuses with congenital Zika virus infection are concordant in not having viral-induced placental inflammation. Special stains reveal proliferation and prominent hyperplasia of placental stromal macrophages, termed Hofbauer cells, in the chorionic villi of infected placentas. Zika virus infection is present in Hofbauer cells from second and third trimester placentas. Experimental studies and placentae from infected fetuses reveal that the spectrum of placental cell types infected with the Zika virus is broader during the first trimester than later in gestation. Inflammatory abnormalities of the placenta are not a component of vertical transmission of the Zika virus. The major placental response in second and third trimester transplacental Zika virus infection is proliferation and hyperplasia of Hofbauer cells, which also demonstrate viral infection.

  15. Infection of bone marrow cells by dengue virus in vivo.

    Science.gov (United States)

    Noisakran, Sansanee; Onlamoon, Nattawat; Hsiao, Hui-Mien; Clark, Kristina B; Villinger, Francois; Ansari, Aftab A; Perng, Guey Chuen

    2012-03-01

    Abnormal bone marrow (BM) suppression is one of the hallmarks of dengue virus (DENV) infection in patients. Although the etiology remains unclear, direct viral targeting of the BM has been reasoned to be a contributing factor. The present studies were carried out in an effort to determine the potential effect of DENV infection on the cellularity of BM using a previously established nonhuman primate model of DENV-induced coagulopathy. BM aspirates were collected at various times from the infected nonhuman primate and cells were phenotypically defined and isolated using standard flow cytometry (fluorescence-activated cell sorting). These isolated cells were subjected to detection of DENV utilizing quantitative real-time reverse transcription polymerase chain reaction, electron microscopy, and immunostaining techniques. DENV RNA was detectable by quantitative real-time reverse transcription polymerase chain reaction in BM specimens and the presence of DENV-like particles within platelet was confirmed by electron microscopy. Enumeration of BM cells revealed a transient surge in cellularity at day 1, followed by a gradual decline from days 2 to 10 post infection. Detailed phenotypic studies showed similar kinetics in the frequencies of CD41(+)CD61(+) cells, regardless of CD34 and CD45 expression. The CD61(+) cells were not only the predominant cells that stained for DENV antigen but fluorescence-activated cell sorting-assisted isolation of CD61(+) cells from the BM were shown to contain infectious DENV by coculture with Vero cells. These data support the view that intravenous infection of nonhuman primate with DENV leads to direct infection of the BM, which is likely to be a contributing factor for transient cell suppression in the peripheral blood characteristic of acute DENV infection.

  16. Mechanics governs single-cell signaling and multi-cell robustness in biofilm infections

    Science.gov (United States)

    Gordon, Vernita

    In biofilms, bacteria and other microbes are embedded in extracellular polymers (EPS). Multiple types of EPS can be produced by a single bacterial strain - the reasons for this redundancy are not well-understood. Our work suggests that different polymers may confer distinct mechanical benefits. Our model organism is Pseudomonas aeruginosa, an opportunistic human pathogen that forms chronic biofilm infections associated with increased antibiotic resistance and evasion of the immune defense. Biofilms initiate when bacteria attach to a surface, sense the surface, and change their gene expression. Changes in gene expression are regulated by a chemical signal, cyclic-di-GMP. We find that one EPS material, called ``PEL,'' enhances surface sensing by increasing mechanical coupling of single bacteria to the surface. Measurements of bacterial motility suggest that PEL may increase frictional interactions between the surface and the bacteria. Consistent with this, we show that bacteria increase cyclic-di-GMP signaling in response to mechanical shear stress. Mechanosensing has long been known to be important to the function of cells in higher eukaryotes, but this is one of only a handful of studies showing that bacteria can sense and respond to mechanical forces. For the mature biofilm, the embedding polymer matrix can protect bacteria both chemically and mechanically. P. aeruginosa infections in the cystic fibrosis (CF) lung often last for decades, ample time for the infecting strain(s) to evolve. Production of another EPS material, alginate, is well-known to tend to increase over time in CF infections. Alginate chemically protects biofilms, but also makes them softer and weaker. Recently, it is being increasingly recognized that bacteria in chronic CF infections also evolve to increase PSL production. We use oscillatory bulk rheology to determine the unique contributions of EPS materials to biofilm mechanics. Unlike alginate, increased PSL stiffens biofilms. Increasing both

  17. Use of indium-111-labeled white blood cells in the diagnosis of diabetic foot infections

    Energy Technology Data Exchange (ETDEWEB)

    Zeiger, L.S.; Fox, I.M.

    1990-01-01

    The diagnosis of bone infection in the patient with nonvirgin bone is a diagnostic dilemma. This is especially true in the diabetic patient with a soft tissue infection and an underlying osteoarthropathy. The authors present a retrospective study using the new scintigraphic technique of indium-111-labeled white blood cells as a method of attempting to solve this diagnostic dilemma.

  18. T-Cell Tropism of Simian Varicella Virus during Primary Infection

    NARCIS (Netherlands)

    W.J.D. Ouwendijk (Werner ); R. Mahalingam (Ravi); R.L. de Swart (Rik); B.L. Haagmans (Bart); G. van Amerongen (Geert); S. Getu (Sarah); D. Gilden (Don); A.D.M.E. Osterhaus (Albert); G.M.G.M. Verjans (George)

    2013-01-01

    textabstractVaricella-zoster virus (VZV) causes varicella, establishes a life-long latent infection of ganglia and reactivates to cause herpes zoster. The cell types that transport VZV from the respiratory tract to skin and ganglia during primary infection are unknown. Clinical, pathological,

  19. Optimization of Assays to Assess Dendritic Cell Activation and/or Energy in Ebola Infection

    Science.gov (United States)

    2011-10-01

    cells, because mouse-adapted Ebola viruses are lethal by this route but not by several other routes of infection. By identifying targets of virus ...immunity by Ebola and Lassa viruses . J Immunol 170 (6), 2797-2801 (2003). APPENDICES: None ...for Public Release; Distribution Unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT The immune responses during lethal virus infection and

  20. Regulation of Noxa-mediated apoptosis in Helicobacter pylori-infected gastric epithelial cells.

    Science.gov (United States)

    Rath, Suvasmita; Das, Lopamudra; Kokate, Shrikant Babanrao; Pratheek, B M; Chattopadhyay, Subhasis; Goswami, Chandan; Chattopadhyay, Ranajoy; Crowe, Sheila Eileen; Bhattacharyya, Asima

    2015-03-01

    Helicobacter pylori induces the antiapoptotic protein myeloid cell leukemia 1 (Mcl1) in human gastric epithelial cells (GECs). Apoptosis of oncogenic protein Mcl1-expressing cells is mainly regulated by Noxa-mediated degradation of Mcl1. We wanted to elucidate the status of Noxa in H. pylori-infected GECs. For this, various GECs such as AGS, MKN45, and KATO III were either infected with H. pylori or left uninfected. The effect of infection was examined by immunoblotting, immunoprecipitation, chromatin immunoprecipitation assay, in vitro binding assay, flow cytometry, and confocal microscopy. Infected GECs, surgical samples collected from patients with gastric adenocarcinoma as well as biopsy samples from patients infected with H. pylori showed significant up-regulation of both Mcl1 and Noxa compared with noninfected samples. Coexistence of Mcl1 and Noxa was indicative of an impaired Mcl-Noxa interaction. We proved that Noxa was phosphorylated at Ser(13) residue by JNK in infected GECs, which caused cytoplasmic retention of Noxa. JNK inhibition enhanced Mcl1-Noxa interaction in the mitochondrial fraction of infected cells, whereas overexpression of nonphosphorylatable Noxa resulted in enhanced mitochondria-mediated apoptosis in the infected epithelium. Because phosphorylation-dephosphorylation can regulate the apoptotic function of Noxa, this could be a potential target molecule for future treatment approaches for H. pylori-induced gastric cancer.

  1. Pronounced phenotype in activated regulatory T cells during a chronic helminth infection.

    Science.gov (United States)

    Layland, Laura E; Mages, Jörg; Loddenkemper, Christoph; Hoerauf, Achim; Wagner, Hermann; Lang, Roland; da Costa, Clarissa U Prazeres

    2010-01-15

    Although several markers have been associated with the characterization of regulatory T cells (Tregs) and their function, no studies have investigated the dynamics of their phenotype during infection. Since the necessity of Tregs to control immunopathology has been demonstrated, we used the chronic helminth infection model Schistosoma mansoni to address the impact on the Treg gene repertoire. Before gene expression profiling, we first studied the localization and Ag-specific suppressive nature of classically defined Tregs during infection. The presence of Foxp3+ cells was predominantly found in the periphery of granulomas and isolated CD4+CD25(hi)Foxp3+ Tregs from infected mice and blocked IFN-gamma and IL-10 cytokine secretion from infected CD4+CD25- effector T cells. Furthermore, the gene expression patterns of Tregs and effector T cells showed that 474 genes were significantly regulated during schistosomiasis. After k-means clustering, we identified genes exclusively regulated in all four populations, including Foxp3, CD103, GITR, OX40, and CTLA-4--classic Treg markers. During infection, however, several nonclassical genes were upregulated solely within the Treg population, such as Slpi, Gzmb, Mt1, Fabp5, Nfil3, Socs2, Gpr177, and Klrg1. Using RT-PCR, we confirmed aspects of the microarray data and also showed that the expression profile of Tregs from S. mansoni-infected mice is simultaneously unique and comparable with Tregs derived from other infections.

  2. The gamma-2-herpesvirus bovine herpesvirus 4 causes apoptotic infection in permissive cell lines.

    Science.gov (United States)

    Sciortino, M T; Perri, D; Medici, M A; Foti, M; Orlandella, B M; Mastino, A

    2000-11-10

    Increasing evidence suggests that regulation of apoptosis in infected cells is associated with several viral infections. The gammaherpesvirus bovine herpesvirus 4 (BHV-4) has been shown to harbor genes with antiapoptotic potentialities. However, here we have demonstrated that productive infection of adherent, permissive cell lines by BHV-4 resulted in a cytopathic effect characterized by induction of apoptosis. This phenomenon was confirmed using different techniques to detect apoptosis and using different virus strains and cell targets. Apoptosis induced by BHV-4 was inhibited by (1) treatment with doses of heparin, which completely inhibited virus attachment and infectivity; (2) UV treatment, which completely abrogated infectivity; and (3) treatment with a dose of phosphonoacetic acid, which blocked virus replication. Virus-induced apoptosis was associated with a down-regulation of Bcl-2 expression and was reduced by Z-VAD-FMK, but not by Z-DEVD-FMK (caspase-3-specific) caspase inhibitors. Inhibition of apoptosis by Z-VAD-FMK treatment during infection did not modify virus yield. Therefore, despite the presence of antiapoptotic genes in its genoma, BHV-4 could complete its cycle of productive infection while inducing apoptosis of infected cells. This finding might have implications for the pathobiology of BHV-4 and other gammaherpesviruses in vivo. Copyright 2000 Academic Press.

  3. Transcriptional profiles of chicken embryo cell cultures following infection with infectious bursal disease virus

    DEFF Research Database (Denmark)

    Li, Yiping; Handberg, K.J.; Juul-Madsen, H.R.

    2007-01-01

    -host interaction, we measured steady-state levels of transcripts from 28 cellular genes of chicken embryo (CE) cell cultures infected with IBDV vaccine stain Bursine-2 during a 7-day infection course by use of the quantitative real-time RT-PCR SYBR green method. Of the genes tested, 21 genes (IRF-1, IFN 1...

  4. Mucosal Mast Cells Response in the Jejunum of Ascaridia galli-Infected Laying Hens

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    Darmawi

    2013-08-01

    Full Text Available Intestinal defense mechanism against helminthes parasitic nematode to be associated with mucosal mast cells reaction. The aim of this research was to examine the effect of infection by Ascaridia galli parasite to trigger mucosal defense based on mucosal mast cells response in laying hens. Amount of ten head laying hens 12-wk old were divided into two groups containing five chickens of each. The first group, chickens were left as un-infected controls. The second group, chickens were infected orally with 1,000 embryonated eggs of A. galli. Mucosal mast cell responses were assayed by in situ jejunal mast cell counts in stained serial histological sections with Alcian blue (pH 0.3 and Safranin-O (pH 0.1 of the jejunum. Mucosal mast cells response were observed and counted on days 14 post infection. The result showed that A. galli infection was able to increase significantly (P<0.05 mast cells response. This research concluded that the A. galli infection can trigger the involment of mucosal mast cells response in jejunal defense of laying hens against parasitic diseases caused by A. galli.

  5. TCF1 Is Required for the T Follicular Helper Cell Response to Viral Infection

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    Tuoqi Wu

    2015-09-01

    Full Text Available T follicular helper (TFH and T helper 1 (Th1 cells generated after viral infections are critical for the control of infection and the development of immunological memory. However, the mechanisms that govern the differentiation and maintenance of these two distinct lineages during viral infection remain unclear. We found that viral-specific TFH and Th1 cells showed reciprocal expression of the transcriptions factors TCF1 and Blimp1 early after infection, even before the differential expression of the canonical TFH marker CXCR5. Furthermore, TCF1 was intrinsically required for the TFH cell response to viral infection; in the absence of TCF1, the TFH cell response was severely compromised, and the remaining TCF1-deficient TFH cells failed to maintain TFH-associated transcriptional and metabolic signatures, which were distinct from those in Th1 cells. Mechanistically, TCF1 functioned through forming negative feedback loops with IL-2 and Blimp1. Our findings demonstrate an essential role of TCF1 in TFH cell responses to viral infection.

  6. Dendritic cells as Achilles' heel and Trojan horse during varicella zoster virus infection

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    Günther eSchönrich

    2015-05-01

    Full Text Available Varicella zoster virus (VZV, a human alphaherpesvirus, causes varicella and subsequently estab-lishes latency within sensory nerve ganglia. Later in life VZV can reactivate to cause herpes zoster. A reduced frequency of VZV-specific T cells is strongly associated with herpes zoster illustrating that these immune cells are central to control latency. Dendritic cells (DCs are required for the generation of VZV-specific T cells. However, DCs can also be infected in vitro and in vivo allowing VZV to evade the antiviral immune response. Thus, DCs represent the immune systems’ Achilles heel. Uniquely among the human herpesviruses, VZV infects both DCs and T cells, and exploits both as Trojan horses. During primary infection VZV-infected DCs traffic to the draining lymph nodes and tonsils, where the virus is transferred to T cells. VZV-infected T cells subsequently spread infection throughout the body to give the typical varicella skin rash. The delicate interplay between VZV and DCs and its consequences for viral immune evasion and viral dissemination will be discussed in this article.

  7. Host and viral factors contributing to CD8+ T cell failure in hepatitis C virus infection

    Institute of Scientific and Technical Information of China (English)

    Christoph Neumann-Haefelin; Hans Christian Spangenberg; Hubert E Blum; Robert Thimme

    2007-01-01

    Virus-specific CD8+ T cells are thought to be the major anti-viral effector cells in hepatitis C virus (HCV)infection. Indeed, viral clearance is associated with vigorous CD8+ T cell responses targeting multiple epitopes. In the chronic phase of infection, HCV-specific CD8+ T cell responses are usually weak, narrowly focused and display often functional defects regarding cytotoxicity, cytokine production, and proliferative capacity. In the last few years, different mechanisms which might contribute to the failure of HCV-specific CD8+ T cells in chronic infection have been identified,including insufficient CD4+ help, deficient CD8+ T cell differentiation, viral escape mutations, suppression by viral factors, inhibitory cytokines, inhibitory ligands, and regulatory T cells. In addition, host genetic factors such as the host's human leukocyte antigen (HLA) background may play an important role in the efficiency of the HCVspecific CD8+ T cell response and thus outcome of infection. The growing understanding of the mechanisms contributing to T cell failure and persistence of HCV infection will contribute to the development of successful immunotherapeutical and -prophylactical strategies.

  8. Psoralen/UV inactivation of HIV-1-infected cells for use in cytologic and immunologic procedures

    Energy Technology Data Exchange (ETDEWEB)

    Watson, A.J.; Klaniecki, J.; Hanson, C.V. (Oncogen Corporation, Seattle, WA (USA))

    1990-04-01

    A rapid procedure for the inactivation of HIV-1-infected cells using psoralen and ultraviolet (UV) light is described. Exposure of HIV-1-infected cells to 5 micrograms/ml psoralen followed by UV irradiation (320-380 nm) for 5 minutes yields cells that are noninfectious as assessed by extended infectivity assays. The psoralen/UV inactivation procedure described is effective with cells chronically or acutely infected with HIV-1 and is unaffected by cell densities up to 12 x 10(6)/ml. At 5 micrograms/ml psoralen does little damage to cellular permeability as shown by the ability of treated cells to exclude trypan blue and propidium iodide. Psoralen/UV treatment of HIV-1-infected cells does not cause a significant decrease in the reactivity of HIV-1 core and envelope antigens or cellular antigens to monoclonal antibodies. Experiments are presented demonstrating the use of these cells for flow cytometry studies and for cell surface labeling using the lactoperoxidase {sup 125}I iodination procedure.

  9. Lack of PPARγ in myeloid cells confers resistance to Listeria monocytogenes infection.

    Directory of Open Access Journals (Sweden)

    Zeinab Abdullah

    Full Text Available The peroxisomal proliferator-activated receptor γ (PPARγ is a nuclear receptor that controls inflammation and immunity. Innate immune defense against bacterial infection appears to be compromised by PPARγ. The relevance of PPARγ in myeloid cells, that organize anti-bacterial immunity, for the outcome of immune responses against intracellular bacteria such as Listeria monocytogenes in vivo is unknown. We found that Listeria monocytogenes infection of macrophages rapidly led to increased expression of PPARγ. This prompted us to investigate whether PPARγ in myeloid cells influences innate immunity against Listeria monocytogenes infection by using transgenic mice with myeloid-cell specific ablation of PPARγ (LysMCre×PPARγ(flox/flox. Loss of PPARγ in myeloid cells results in enhanced innate immune defense against Listeria monocytogenes infection both, in vitro and in vivo. This increased resistance against infection was characterized by augmented levels of bactericidal factors and inflammatory cytokines: ROS, NO, IFNγ TNF IL-6 and IL-12. Moreover, myeloid cell-specific loss of PPARγ enhanced chemokine and adhesion molecule expression leading to improved recruitment of inflammatory Ly6C(hi monocytes to sites of infection. Importantly, increased resistance against Listeria infection in the absence of PPARγ was not accompanied by enhanced immunopathology. Our results elucidate a yet unknown regulatory network in myeloid cells that is governed by PPARγ and restrains both listeriocidal activity and recruitment of inflammatory monocytes during Listeria infection, which may contribute to bacterial immune escape. Pharmacological interference with PPARγ activity in myeloid cells might represent a novel strategy to overcome intracellular bacterial infection.

  10. iNOS-producing inflammatory dendritic cells constitute the major infected cell type during the chronic Leishmania major infection phase of C57BL/6 resistant mice.

    Directory of Open Access Journals (Sweden)

    Carl De Trez

    2009-06-01

    Full Text Available Leishmania major parasites reside and multiply in late endosomal compartments of host phagocytic cells. Immune control of Leishmania growth absolutely requires expression of inducible Nitric Oxide Synthase (iNOS/NOS2 and subsequent production of NO. Here, we show that CD11b+ CD11c+ Ly-6C+ MHC-II+ cells are the main iNOS-producing cells in the footpad lesion and in the draining lymph node of Leishmania major-infected C57BL/6 mice. These cells are phenotypically similar to iNOS-producing inflammatory DC (iNOS-DC observed in the mouse models of Listeria monocytogenes and Brucella melitensis infection. The use of DsRed-expressing parasites demonstrated that these iNOS-producing cells are the major infected population in the lesions and the draining lymph nodes. Analysis of various genetically deficient mouse strains revealed the requirement of CCR2 expression for the recruitment of iNOS-DC in the draining lymph nodes, whereas their activation is strongly dependent on CD40, IL-12, IFN-gamma and MyD88 molecules with a partial contribution of TNF-alpha and TLR9. In contrast, STAT-6 deficiency enhanced iNOS-DC recruitment and activation in susceptible BALB/c mice, demonstrating a key role for IL-4 and IL-13 as negative regulators. Taken together, our results suggest that iNOS-DC represent a major class of Th1-regulated effector cell population and constitute the most frequent infected cell type during chronic Leishmania major infection phase of C57BL/6 resistant mice.

  11. Infection of Ixodes spp. tick cells with different Anaplasma phagocytophilum isolates induces the inhibition of apoptotic cell death.

    Science.gov (United States)

    Alberdi, Pilar; Ayllón, Nieves; Cabezas-Cruz, Alejandro; Bell-Sakyi, Lesley; Zweygarth, Erich; Stuen, Snorre; de la Fuente, José

    2015-09-01

    Anaplasma phagocytophilum is an intracellular rickettsial pathogen transmitted by Ixodes spp. ticks, which causes granulocytic anaplasmosis in humans, horses and dogs and tick-borne fever (TBF) in ruminants. In the United States, human granulocytic anaplasmosis (HGA) is highly prevalent while TBF has not been reported. However, in Europe the situation is the opposite, with high prevalence for TBF in sheep and low prevalence of HGA. The origin of these differences has not been identified and our hypothesis is that different A. phagocytophilum isolates impact differently on tick vector capacity through inhibition of apoptosis to establish infection of the tick vector. In this study we used three different isolates of A. phagocytophilum of human, canine and ovine origin to infect the Ixodes ricinus-derived cell line IRE/CTVM20 and the Ixodes scapularis-derived cell line ISE6 in order to characterize the effect of infection on the level of tick cell apoptosis. Inhibition of apoptosis was observed by flow cytometry as early as 24h post-infection for both tick cell lines and all three isolates of A. phagocytophilum, suggesting that pathogen infection inhibits apoptotic pathways to facilitate infection independently of the origin of the A. phagocytophilum isolate and tick vector species. However, infection with A. phagocytophilum isolates inhibited the intrinsic apoptosis pathway at different levels in I. scapularis and I. ricinus cells. These results suggested an impact of vector-pathogen co-evolution on the adaptation of A. phagocytophilum isolates to grow in tick cells as each isolate grew better in the tick cell line derived from its natural vector species. These results increase our understanding of the mechanisms of A. phagocytophilum infection and multiplication and suggest that multiple mechanisms may affect disease prevalence in different geographical regions.

  12. Quantitative proteomics of Spodoptera frugiperda cells during growth and baculovirus infection.

    Science.gov (United States)

    Carinhas, Nuno; Robitaille, Aaron Mark; Moes, Suzette; Carrondo, Manuel José Teixeira; Jenoe, Paul; Oliveira, Rui; Alves, Paula Marques

    2011-01-01

    Baculovirus infection of Spodoptera frugiperda cells is a system of choice to produce a range of recombinant proteins, vaccines and, potentially, gene therapy vectors. While baculovirus genomes are well characterized, the genome of S. frugiperda is not sequenced and the virus-host molecular interplay is sparsely known. Herein, we describe the application of stable isotope labeling by amino acids in cell culture (SILAC) to obtain the first comparative proteome quantitation of S. frugiperda cells during growth and early baculovirus infection. The proteome coverage was maximized by compiling a search database with protein annotations from insect species. Of interest were differentially proteins related to energy metabolism, endoplasmic reticulum and oxidative stress, yet not investigated in the scope of baculovirus infection. Further, the reduced expression of key viral-encoded proteins early in the infection cycle is suggested to be related with decreased viral replication at high cell density culture. These findings have implications for virological research and improvement of baculovirus-based bioprocesses.

  13. Early Events in Chikungunya Virus Infection-From Virus Cell Binding to Membrane Fusion.

    Science.gov (United States)

    van Duijl-Richter, Mareike K S; Hoornweg, Tabitha E; Rodenhuis-Zybert, Izabela A; Smit, Jolanda M

    2015-07-07

    Chikungunya virus (CHIKV) is a rapidly emerging mosquito-borne alphavirus causing millions of infections in the tropical and subtropical regions of the world. CHIKV infection often leads to an acute self-limited febrile illness with debilitating myalgia and arthralgia. A potential long-term complication of CHIKV infection is severe joint pain, which can last for months to years. There are no vaccines or specific therapeutics available to prevent or treat infection. This review describes the critical steps in CHIKV cell entry. We summarize the latest studies on the virus-cell tropism, virus-receptor binding, internalization, membrane fusion and review the molecules and compounds that have been described to interfere with virus cell entry. The aim of the review is to give the reader a state-of-the-art overview on CHIKV cell entry and to provide an outlook on potential new avenues in CHIKV research.

  14. White blood cell scintigraphy for differentiation of infection and aseptic loosening

    DEFF Research Database (Denmark)

    Simonsen, Lene; Buhl, Anna; Oersnes, Thue;

    2007-01-01

    Diagnosis of an infected arthroplasty is often difficult. Fever, abnormal physical findings, radiographic changes, findings at bone scintigraphy, an elevated erythrocyte sedimentation rate, CRP, and leucocytosis are not specific enough. We evaluated the diagnostic value of white blood cell...

  15. Dendritic cells in hepatitis C virus infection: key players in the IFNL3-genotype response.

    Science.gov (United States)

    O'Connor, Kate S; George, Jacob; Booth, David; Ahlenstiel, Golo

    2014-12-21

    Recently, single nucleotide polymorphisms, in the vicinity of the interferon lambda 3 (IFNL3) gene have been identified as the strongest predictor of spontaneous and treatment induced clearance of hepatitis C virus (HCV) infection. Since then, increasing evidence has implicated the innate immune response in mediating the IFNL3 genotype effect. Dendritic cells (DCs) are key to the host immune response in HCV infection and their vital role in the IFNL3 genotype effect is emerging. Reports have identified subclasses of DCs, particularly myeloid DC2s and potentially plasmacytoid DCs as the major producers of IFNL3 in the setting of HCV infection. Given the complexities of dendritic cell biology and the conflicting current available data, this review aims to summarize what is currently known regarding the role of dendritic cells in HCV infection and to place it into context of what is know about lambda interferons and dendritic cells in general.

  16. Pseudomonas aeruginosa airway infection recruits and modulates neutrophilic myeloid-derived suppressor cells

    Directory of Open Access Journals (Sweden)

    Hasan Halit Öz

    2016-11-01

    Full Text Available Pseudomonas aeruginosa is an opportunistic pathogen that causes infections mainly in patients with cystic fibrosis (CF lung disease. Despite innate and adaptive immune responses upon infection, P. aeruginosa is capable of efficiently escaping host defenses, but the underlying immune mechanisms remain poorly understood. Myeloid-derived suppressor cells (MDSCs are innate immune cells that are functionally characterized by their potential to suppress T- and natural killer (NK-cell responses. Here we demonstrate, using an airway in vivo infection model, that P. aeruginosa recruits and activates neutrophilic MDSCs, which functionally suppress T-cell responses. We further show that the CF gene defect (cystic fibrosis transmembrane conductance regulator, CFTR modulates the functionality, but not the recruitment or generation of neutrophilic MDSCs. Collectively, we define a mechanism by which P. aeruginosa airway infection undermines host immunity by modulating neutrophilic MDSCs in vivo.

  17. Ethanol suppression of peripheral blood mononuclear cell trafficking across brain endothelial cells in immunodeficiency virus infection

    Directory of Open Access Journals (Sweden)

    Lola C Hudson

    2010-01-01

    Full Text Available Lola C Hudson1, Brenda A Colby1, Rick B Meeker21Department of Molecular Biosciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA; 2Department of Neurology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USAAbstract: Earlier studies suggested that the combination of alcohol use and immunodeficiency virus infection resulted in more severe neurologic disease than either condition individually. These deleterious interactions could be due to increased immune cell and virus trafficking or may result from interactions between ethanol and human immunodeficiency virus (HIV-associated toxicity within the brain. To determine the extent to which increased trafficking played a role, we examined the effect of ethanol on the migration of different peripheral blood mononuclear cell (PBMCs subsets across a brain endothelial cell monolayer. We utilized combinations of feline brain endothelial cells with astrocytes, and/or microglia with either acute exposure to 0.08 g/dL ethanol, a combination of ethanol and feline immunodeficiency virus (FIV, or FIV alone. Adherence of PBMCs to endothelium was increased in all combinations of cells with the addition of ethanol. Despite increased PBMC adhesion with ethanol treatment, transmigration of B cells, monocytes, CD4 T cells and CD8 T cells was not increased and was actually decreased in the presence of astrocytes. Expression of three common adhesion molecules, intercellular adhesion molecule-1 (ICAM1, ICAM2, and vascular cell adhesion molecule, was unchanged or slightly decreased by ethanol.