543 research outputs found
Trumped: How Donald J. Trump Defied the Odds and Won the Presidency
Against all odds, Donald J. Trump shocked the world when he won the 2016 presidential election and became the 45th President of the United States. Few foresaw such a victory for the Republicans; it was widely believed among political scientists, election analysts, media pundits, and reportedly even Trump himself that victory would ultimately go to the Democratic party. So how and why did he win? We examine the multitude of factors that contributed to his electoral victory, including his iconic “Make America Great Again” campaign, how his policies resonated with voters (as well as his primary opponent’s policies), and shifts in voters’ party preferences prompted by racial diversity. Our findings indicate that his campaign was boosted most by strategically using social media, having a message that resonated with supporters of the rising Populist movement, and aggressively campaigning in swing states. We also found that his primary opponent, Hillary Clinton, failed to attract key swing voters, many of which instead voted for Trump. Finally, we found that diversity increases Democratic or Republican party support among particular social groups based on the level of diversity in an area, thus prompting some of the unexpected electoral outcomes of the election.https://engagedscholarship.csuohio.edu/u_poster_2018/1009/thumbnail.jp
Macropinocytosis in Different Cell Types: Similarities and Differences
Macropinocytosis is a unique pathway of endocytosis characterised by the nonspecific internalisation of large amounts of extracellular fluid, solutes and membrane in large endocytic vesicles known as macropinosomes. Macropinocytosis is important in a range of physiological processes, including antigen presentation, nutrient sensing, recycling of plasma proteins, migration and signalling. It has become apparent in recent years from the study of specialised cells that there are multiple pathways of macropinocytosis utilised by different cell types, and some of these pathways are triggered by different stimuli. Understanding the physiological function of macropinocytosis requires knowledge of the regulation and fate of the macropinocytosis pathways in a range of cell types. Here, we compare the mechanisms of macropinocytosis in different primary and immortalised cells, identify the gaps in knowledge in the field and discuss the potential approaches to analyse the function of macropinocytosis in vivo
Initiation of Autoimmune Diabetes by Developmentally Regulated Presentation of Islet Cell Antigens in the Pancreatic Lymph Nodes
Little is known about the events triggering lymphocyte invasion of the pancreatic islets in prelude to autoimmune diabetes. For example, where islet-reactive T cells first encounter antigen has not been identified. We addressed this issue using BDC2.5 T cell receptor transgenic mice, which express a receptor recognizing a natural islet beta cell antigen. In BDC2.5 animals, activated T cells were found only in the islets and the lymph nodes draining them, and there was a close temporal correlation between lymph node T cell activation and islet infiltration. When naive BDC2.5 T cells were transferred into nontransgenic recipients, proliferating cells were observed only in pancreatic lymph nodes, and this occurred significantly before insulitis was detectable. Surprisingly, proliferation was not seen in 10-day-old recipients. This age-dependent dichotomy was reproduced in a second transfer system based on an unrelated antigen artificially expressed on beta cells. We conclude that beta cell antigens are transported specifically to pancreatic lymph nodes, where they trigger reactive T cells to invade the islets. Systemic or extrapancreatic T cell priming, indicative of activation via molecular mimicry or superantigens, was not seen. Compromised presentation of beta cell antigens in the pancreatic lymph nodes of juvenile animals may be the root of a first “checkpoint” in diabetes progression
The Natural Selection of Herpesviruses and Virus-Specific NK Cell Receptors
During the co-evolution of cytomegalovirus (CMV) and natural killer (NK) cells, each has evolved specific tactics in an attempt to prevail. CMV has evolved multiple immune evasion mechanisms to avoid detection by NK cells and other immune cells, leading to chronic infection. Meanwhile, the host has evolved virus-specific receptors to counter these evasion strategies. The natural selection of viral genes and host receptors allows us to observe a unique molecular example of “survival of the fittest”, as virus and immune cells try to out-maneuver one another or for the virus to achieve détente for optimal dissemination in the population
Mpeg1 is not essential for antibacterial or antiviral immunity, but is implicated in antigen presentation.
To control infections phagocytes can directly kill invading microbes. Macrophage-expressed gene 1 (Mpeg1), a pore-forming protein sometimes known as perforin-2, is reported to be essential for bacterial killing following phagocytosis. Mice homozygous for the mutant allele Mpeg1tm1Pod succumb to bacterial infection and exhibit deficiencies in bacterial killing in vitro. Here we describe a new Mpeg mutant allele Mpeg1tm1.1Pib on the C57BL/6J background. Mice homozygous for the new allele are not abnormally susceptible to bacterial or viral infection, and irrespective of genetic background show no perturbation in bacterial killing in vitro. Potential reasons for these conflicting findings are discussed. In further work, we show that cytokine responses to inflammatory mediators, as well as antibody generation, are also normal in Mpeg1tm1.1Pib/tm1.1Pib mice. We also show that Mpeg1 is localized to a CD68-positive endolysosomal compartment, and that it exists predominantly as a processed, two-chain disulfide-linked molecule. It is abundant in conventional dendritic cells 1, and mice lacking Mpeg1 do not present the model antigen ovalbumin efficiently. We conclude that Mpeg1 is not essential for innate antibacterial protection or antiviral immunity, but may play a focused role early in the adaptive immune response
A direct comparison of rejection by CD8 and CD4 T cells in a transgenic model of allotransplantation
Peptide-MHC heterodimers show that thymic positive selection requires a more restricted set of self-peptides than negative selection
T cell selection and maturation in the thymus depends on the interactions between T cell receptors (TCRs) and different self-peptide–major histocompatibility complex (pMHC) molecules. We show that the affinity of the OT-I TCR for its endogenous positively selecting ligands, Catnb-H-2Kb and Cappa1-H-2Kb, is significantly lower than for previously reported positively selecting altered peptide ligands. To understand how these extremely weak endogenous ligands produce signals in maturing thymocytes, we generated soluble monomeric and dimeric peptide–H-2Kb ligands. Soluble monomeric ovalbumin (OVA)-Kb molecules elicited no detectable signaling in OT-I thymocytes, whereas heterodimers of OVA-Kb paired with positively selecting or nonselecting endogenous peptides, but not an engineered null peptide, induced deletion. In contrast, dimer-induced positive selection was much more sensitive to the identity of the partner peptide. Catnb-Kb–Catnb-Kb homodimers, but not heterodimers of Catnb-Kb paired with a nonselecting peptide-Kb, induced positive selection, even though both ligands bind the OT-I TCR with detectable affinity. Thus, both positive and negative selection can be driven by dimeric but not monomeric ligands. In addition, positive selection has much more stringent requirements for the partner self-pMHC
Contrasting Alloreactive CD4 + and CD8 + T Cells: There's More to It Than MHC Restriction
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73698/1/j.1600-6143.2003.00036.x.pd
Ubiquitin-like protein 3 (UBL3) is required for MARCH ubiquitination of major histocompatibility complex class II and CD86
The MARCH E3 ubiquitin (Ub) ligase MARCH1 regulates trafficking of major histocompatibility complex class II (MHC II) and CD86, molecules of critical importance to immunity. Here we show, using a genome-wide CRISPR knockout screen, that ubiquitin-like protein 3 (UBL3) is a necessary component of ubiquitination-mediated trafficking of these molecules in mice and in humans. Ubl3-deficient mice have elevated MHC II and CD86 expression on the surface of professional and atypical antigen presenting cells. UBL3 also regulates MHC II and CD86 in human dendritic cells (DCs) and macrophages. UBL3 impacts ubiquitination of MARCH1 substrates, a mechanism that requires UBL3 plasma membrane anchoring via prenylation. Loss of UBL3 alters adaptive immunity with impaired development of thymic regulatory T cells, loss of conventional type 1 DCs, increased number of trogocytic marginal zone B cells, and defective in vivo MHC II and MHC I antigen presentation. In summary, we identify UBL3 as a conserved, critical factor in MARCH1-mediated ubiquitination with important roles in immune responses
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