Witnessing reconciliation reduces arousal of bystanders in a baboon group (Papio hamadryas hamadryas)

Reconciliation is the occurrence of friendly behaviour between opponents shortly after an aggressive conflict. In primate groups, reconciliation reduces aggression and postconflict arousal. Aggression within a group can also increase arousal of bystanders (e.g. increase bystanders' rates of self-directed behaviour). Since reconciliation reduces aggression between opponents, we tested whether it also reduces self-directed behaviour in bystanders. Following aggression in a captive group of hamadryas baboons, one observer conducted a focal sample on one of the combatants to document reconciliation and a second observer simultaneously conducted a focal sample on a randomly selected bystander. Matched control observations were then collected on the same individuals in a nonaggressive context to obtain baseline levels of behaviour. The self-directed behaviour of bystanders was elevated after witnessing a fight compared to baseline levels. If combatants reconciled aggression, bystander rates of self-directed behaviour significantly decreased. If combatants did not reconcile aggression, bystander rates of self-directed behaviour remained at elevated levels, significantly higher than after reconciliation. If combatants affiliated with partners other than their original opponent, bystander rates of self-directed behaviour did not decrease. The rate of bystander self-directed behaviour after a combatant affiliated with its opponent was significantly lower than the rate after a combatant affiliated with other animals. Witnessing aggression increased arousal in bystanders, and reconciliation between the combatants was accompanied by reduced bystander arousal. The reduction was specific to contexts in which former opponents interacted. We suggest that bystanders recognized the functional significance of this conflict-resolution mechanism when it occurred in their group. (c) 2013 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

How HIV takes advantage of the cytoskeleton in entry and replication

The host cell cytoskeleton plays a key role in the life cycle of viral pathogens whose propagation depends on mandatory intracellular steps. Accordingly, also the human immunodeficiency virus type 1 (HIV-1) has evolved strategies to exploit and modulate in particular the actin cytoskeleton for its purposes. This review will recapitulate recent findings on how HIV-1 hijacks the cytoskeleton to facilitate entry into, transport within and egress from host cells as well as to commandeer communication of infected with uninfected bystander cells.

Therapeutic protein transduction of mammalian cells and mice by nucleic acid-free lentiviral nanoparticles

The straightforward production and dose-controlled administration of protein therapeutics remain major challenges for the biopharmaceutical manufacturing and gene therapy communities. Transgenes linked to HIV-1-derived vpr and pol-based protease cleavage (PC) sequences were co-produced as chimeric fusion proteins in a lentivirus production setting, encapsidated and processed to fusion peptide-free native protein in pseudotyped lentivirions for intracellular delivery and therapeutic action in target cells. Devoid of viral genome sequences, protein-transducing nanoparticles (PTNs) enabled transient and dose-dependent delivery of therapeutic proteins at functional quantities into a variety of mammalian cells in the absence of host chromosome modifications. PTNs delivering Manihot esculenta linamarase into rodent or human, tumor cell lines and spheroids mediated hydrolysis of the innocuous natural prodrug linamarin to cyanide and resulted in efficient cell killing. Following linamarin injection into nude mice, linamarase-transducing nanoparticles impacted solid tumor development through the bystander effect of cyanide.

CD69 upregulation on T cells as an in vitro marker for delayed-type drug hypersensitivity

BACKGROUND: T cells play a key role in delayed-type drug hypersensitivity reactions. Their reactivity can be assessed by their proliferation in response to the drug in the lymphocyte transformation test (LTT). However, the LTT imposes limitations in terms of practicability, and an alternative method that is easier to implement than the LTT would be desirable. METHODS: Four months to 12 years after acute drug hypersensitivity reactions, CD69 upregulation on T cells of 15 patients and five healthy controls was analyzed by flow cytometry. RESULTS: All 15 LTT-positive patients showed a significant increase of CD69 expression on T cells after 48 h of drug-stimulation exclusively with the drugs incriminated in drug-hypersensitivities. A stimulation index of 2 as cut-off value allowed discrimination between nonreactive and reactive T cells in LTT and CD69 upregulation. T cells (0.5-3%) showed CD69 up-regulation. The reactive cell population consisted of a minority of truly drug reactive T cells secreting cytokines and a higher number of bystander T cells activated by IL-2 and possibly other cytokines. CONCLUSIONS: CD69 upregulation was observed after 2 days in all patients with a positive LTT after 6 days, thus appearing to be a promising tool to identify drug-reactive T cells in the peripheral blood of patients with drug-hypersensitivity reactions.

Host responses to intestinal microbial antigens in gluten-sensitive mice

BACKGROUND AND AIMS: Excessive uptake of commensal bacterial antigens through a permeable intestinal barrier may influence host responses to specific antigen in a genetically predisposed host. The aim of this study was to investigate whether intestinal barrier dysfunction induced by indomethacin treatment affects the host response to intestinal microbiota in gluten-sensitized HLA-DQ8/HCD4 mice. METHODOLOGY/PRINCIPAL FINDINGS: HLA-DQ8/HCD4 mice were sensitized with gluten, and gavaged with indomethacin plus gluten. Intestinal permeability was assessed by Ussing chamber; epithelial cell (EC) ultra-structure by electron microscopy; RNA expression of genes coding for junctional proteins by Q-real-time PCR; immune response by in-vitro antigen-specific T-cell proliferation and cytokine analysis by cytometric bead array; intestinal microbiota by fluorescence in situ hybridization and analysis of systemic antibodies against intestinal microbiota by surface staining of live bacteria with serum followed by FACS analysis. Indomethacin led to a more pronounced increase in intestinal permeability in gluten-sensitized mice. These changes were accompanied by severe EC damage, decreased E-cadherin RNA level, elevated IFN-gamma in splenocyte culture supernatant, and production of significant IgM antibody against intestinal microbiota. CONCLUSION: Indomethacin potentiates barrier dysfunction and EC injury induced by gluten, affects systemic IFN-gamma production and the host response to intestinal microbiota antigens in HLA-DQ8/HCD4 mice. The results suggest that environmental factors that alter the intestinal barrier may predispose individuals to an increased susceptibility to gluten through a bystander immune activation to intestinal microbiota.

Lack of Host Gut Microbiota Alters Immune Responses and Intestinal Granuloma Formation during Schistosomiasis

Fatalities from schistosome infections arise due to granulomatous, immune-mediated responses to eggs that become trapped in host tissues. Schistosome-specific immune responses are characterized by initial Th1 responses and our previous studies demonstrated that Myd88-deficient mice failed to initiate such responses in vivo. Paradoxically, schistosomal antigens fail to stimulate innate cells to release pro-inflammatory cytokines in vitro. Since S. mansoni infection is an intestinal disease, we hypothesized that commensal bacteria could act as bystander activators of the intestinal innate immune system to instigate Th1 responses. Using a broad spectrum of orally-administered antibiotics and antimycotics we analyzed schistosome-infected mice that were simultaneously depleted of gut bacteria. After depletion there was significantly less inflammation in the intestine which was accompanied by decreased intestinal granuloma development. In contrast, liver pathology remained unaltered. In addition, schistosome-specific immune responses were skewed and fecal egg excretion was diminished. This study demonstrates that host microbiota can act as a third partner in instigating helminth-specific immune responses.

Efectos de vecindad de la radiación ionizante y sus implicaciones en radioterapia y radioprotección

En el paradigma clásico, los efectos biológicos de la radiación ionizante se atribuyen al daño en el ADN inducido en cada célula irradiada. La demostración de efectos de vecindad causados por radiación ionizante (EVIR) ha generado un cambio profundo en la concepción actual de la radiobiología. Los EVIR son aquellos efectos causados por la radiación que se producen en células que no han sido irradiadas. Diversos avances técnicos, en particular el empleo de microhaces, han permitido estudiar los EVIR in vitro. Se conocen dos vías por las cuales las células irradiadas pueden comunicarse con las no irradiadas, a saber: mediante uniones especializadas (nexos) que comunican los citoplasmas de células adyacentes, y mediante la secreción de factores solubles al medio extracelular. Estos factores incluyen varias citokinas y especies reactivas del oxígeno y nitrógeno. Las vías de señalización en las células afectadas involucran en particular la activación de proteína kinasas activadas por mitógenos (MAPK) y del factor de transcripción NFciclooxigenasa 2, sintasa de óxido nítrico 2 y NAD(P)H oxidasa. Los EVIR pueden causar mutaciones puntuales y cambios epigenéticos. Los efectos sobre las vías de señalización pueden persistir indefinidamente e incluso transmitirse a la descendencia. Paradójicamente, en ciertas condiciones los EVIR pueden ser adaptativos, es decir que tornan a las células afectadas más resistentes a la radiación. La adaptación exige síntesis de proteínas y mejora la capacidad celular de reparar el ADN y resistir el estrés oxidativo. Los EVIR también se han demostrado in vivo. Por tanto, pueden tener implicaciones importantes en radioterapia, tanto para mejorar la eficacia terapéutica como para reducir la incidencia de efectos adversos. Asimismo, su mejor conocimiento puede influenciar las normas internacionales de radioprotección.

Protective DNA vaccination against organ-specific autoimmunity is highly specific and discriminates between single amino acid substitutions in the peptide autoantigen

DNA vaccines that encode encephalitogenic sequences in tandem can protect from subsequent experimental autoimmune encephalomyelitis induced with the corresponding peptide. The mechanism for this protection and, in particular, if it is specific for the amino acid sequence encoding the vaccine are not known. We show here that a single amino acid exchange in position 79 from serine (nonself) to threonine (self) in myelin basic protein peptide MBP68–85, which is a major encephalitogenic determinant for Lewis rats, dramatically alters the protection. Moreover, vaccines encoding the encephalitogenic sequence MBP68–85 do not protect against the second encephalitogenic sequence MBP89–101 in Lewis rats and vice versa. Thus, protective immunity conferred by DNA vaccination exquisitely discriminates between peptide target autoantigens. No bystander suppression was observed. The exact underlying mechanisms remain elusive because no simple correlation between impact on ex vivo responses and protection against disease were noted.

Tissue-specific expression of herpes simplex virus thymidine kinase gene delivered by adeno-associated virus inhibits the growth of human hepatocellular carcinoma in athymic mice

About 70% of hepatocellular carcinomas are known to express α-fetoprotein, which is normally expressed in fetal but not in adult livers. To induce herpes simplex virus-thymidine kinase expression in these cancer cells, we constructed an adeno-associated viral vector containing the HSV-TK gene under the control of the α-fetoprotein enhancer and albumin promoter. We previously demonstrated in vitro that although this vector can transduce a variety of human cells, only transduced AFP and albumin-expressing hepatocellular carcinoma cell lines were sensitive to killing by ganciclovir (GCV). In the present study, we explored the effect of this vector on hepatocellular carcinoma cells in vivo. Subcutaneous tumors generated in nude mice by implanting hepatocellular carcinoma cells previously transduced with this vector shrank dramatically after treatment with GCV. Bystander effect was also observed on the tumors generated by mixing transduced and untransduced cells. To test whether the tumor cells can be transduced by the virus in vivo, we injected the recombinant adeno-associated virus into tumors generated by untransduced hepatocarcinoma cell line. Tumor growth were retarded after treatment with GCV. These experiments demonstrate the feasibility of in vivo transduction of tumor cell with rAAV.

Correction in trans for Fabry disease: expression, secretion and uptake of alpha-galactosidase A in patient-derived cells driven by a high-titer recombinant retroviral vector.

Fabry disease is an X-linked metabolic disorder due to a deficiency of alpha-galactosidase A (alpha-gal A; EC 3.2.1.22). Patients accumulate glycosphingolipids with terminal alpha-galactosyl residues that come from intracellular synthesis, circulating metabolites, or from the biodegradation Of senescent cells. Patients eventually succumb to renal, cardio-, or cerebrovascular disease. No specific therapy exists. One possible approach to ameliorating this disorder is to target corrective gene transfer therapy to circulating hematopoietic cells. Toward this end, an amphotropic virus-producer cell line has been developed that produces a high titer (>10(6) i.p. per ml) recombinant retrovirus constructed to transduce and correct target cells. Virus-producer cells also demonstrate expression of large amounts of both intracellular and secreted alpha-gal A. To examine the utility of this therapeutic vector, skin fibroblasts from Fabry patients were corrected for the metabolic defect by infection with this recombinant virus and secreted enzyme was observed. Furthermore, the secreted enzyme was found to be taken up by uncorrected cells in a mannose-6-phosphate receptor-dependent manner. In related experiments, immortalized B cell lines from Fabry patients, created as a hematologic delivery test system, were transduced. As with the fibroblasts, transduced patient B cell lines demonstrated both endogenous enzyme correction and a small amount of secretion together with uptake by uncorrected cells. These studies demonstrate that endogenous metabolic correction in transduced cells, combined with secretion, may provide a continuous source of corrective material in trans to unmodified patient bystander cells (metabolic cooperativity).

Expanding the scope of the social response context model

Descriptive models of social response are concerned with identifying and discriminating between different types of response to social influence. In a previous article (Nail, MacDonald, & Levy, 2000), the authors demonstrated that 4 conceptual dimensions are necessary to adequately distinguish between such phenomena as conformity, compliance, contagion, independence, and anticonformity in a single model. This article expands the scope of the authors' 4-dimensional approach by reviewing selected experimental and cultural evidence, further demonstrating the integrative power of the model. This review incorporates political psychology, culture and aggression, self-persuasion, group norms, prejudice, impression management, psychotherapy, pluralistic ignorance, bystander intervention/nonintervention, public policy, close relationships, and implicit attitudes.

Contemporaneous fluctuations in T cell responses to persistent herpes virus infections

The classical paradigm for T cell dynamics suggests that the resolution of a primary acute virus infection is followed by the generation of a long-lived pool of memory T cells that is thought to be highly stable. Very limited alteration in this repertoire is expected until the immune system is re-challenged by reactivation of latent viruses or by cross-reactive pathogens. Contradicting this view, we show here that the T cell repertoire specific for two different latent herpes viruses in the peripheral blood displayed significant contemporaneous co-fluctuations of virus-specific CD8(+) T cells. The coordinated responses to two different viruses suggest that the fluctuations within the T cell repertoire may be driven by sub-clinical viral reactivation or a more generalized 'bystander' effect. The later contention was supported by the observation that, while absolute number of CD3(+) T cells and their subsets and also the cell surface phenotype of antigen-specific T cells remained relatively constant, a loss of CD62L expression in the total CD8(+) T cell population was coincident with the expansion of tetramer-positive virus-specific T cells. This study demonstrates that the dynamic process of T cell expansion and contractions in persistent viral infections is not limited to the acute phase of infection, but also continues during the latent phase of infection.

Higher-order CpG-DNA stimulation reveals distinct activation requirements for marginal zone and follicular B cells in lupus mice

Mouse follicular B cells express TLR9 and respond vigorously to stimulation with single-stranded CpG-oligodeoxynucleotides (ODN). Surprisingly, follicular B cells do not respond to direct stimulation with other TLR9 ligands, such as bacterial DNA or class A(D) CpG-ODN capable of forming higher-order structures, unless other cell types are present. Here, we show that priming with interferons or with B cell-activating factor, or simultaneous co-engagement of the B cell receptor for antigen (BCR), can overcome this unresponsiveness. The effect of interferons occurs at the transcriptional level and is mediated through an autocrine/paracrine loop, which is dependent on IRF-1, IL-6 and IL-12 p40. We hypothesize that the lack of bystander activation of follicular B cells with more complex CpG ligands may be an important safety mechanism for avoiding autoimmunity. This will prevent resting B cells from responding to foreign or self-derived hypomethylated double-stranded CpG ligands unless these ligands are either delivered through the B cell receptor or under conditions where B cells are simultaneously co-engaged by activated plasmacytoid dendritic cells or TH1 cells. A corollary is that the heightened responsiveness of lupus B cells to TLR9-induced stimulation cannot be ascribed to unprimed follicular B cells, but is rather mediated by hypersensitive marginal zone B cells.

Memory conformity: Actors and bystanders

This dissertation explored memory conformity effects on people who interacted with a confederate and of bystanders to that interaction. Two studies were carried out. Study 1 was conducted in the field. A male confederate approached a group of people at the beach and had a brief interaction. About a minute later a research assistant approached the group and administered a target-absent lineup to each person in the group. Analyses revealed that memory conformity occurred during the lineup task. Bystanders were twice as likely to conform as those who interacted with the confederate. Study 2 was carried out in a laboratory under controlled conditions. Participants were exposed to two events during their time in the laboratory. In one event, participants were shown a brief video with no determinate roles assigned. In the other event participants were randomly assigned to interact with a confederate (actor condition) or to witness that interaction (bystander condition). Participants were given memory tests on both events to understand the effects of participant role (actor vs. bystander) on memory conformity. Participants answered second to all questions, following a confederate acting as a participant, who disseminated misinformation on critical questions. Analyses revealed no significant differences in memory conformity between actors and bystanders during the movie memory task. However, differences were found for the interaction memory task such that bystanders conformed more than actors on two of four critical questions. Bystanders also conformed more than actors during a lineup identification task. The results of these studies suggest that the role a person plays in an interaction affects how susceptible they are to information from a co-witness. Theoretical and applied implications are discussed. First, the results are explained through the use of two models of memory. Second, recommendations are made for forensic investigators.

Time Delays on the Identification of the Need for CPR for Limited English Proficient 9-1-1 Callers

Thesis (Master's)--University of Washington, 2016-08