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Showing 1 to 20 of 32 for “"antigenic variation"”.
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Antigenic Variation in Candida Albicans
The antigenicity of the germ tube and the yeast phase of Candida albicans have been compared by crossed immunoelectrophoresis, tandem-crossed immunoelectrophoresis and classical immunoelectrophoresis. Qualitative and quantitative differences between the two growth forms have been observed. One …
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Antigenic Variation and Telomere Structure in Trypanosoma brucei
<p>Trypanosoma brucei survives immune attack in its mammalian hosts by periodically changing the variant surface glycoprotein (VSG). From the ~1000 VSG genes (VSGs) scattered throughout the genome, a few are located at telomere loci called expression sites (ESs) and only one is expressed at any …
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Characterization of a Novel Sensing Mechanism Governing Antigenic Variation in P. Falciparum
… exclusive manner. var genes encode the chief antigenic and virulence determinant of P. falciparum, PfEMP1, and switching between active genes results in antigenic variation, allowing the parasite to evade the human immune system and cause chronic infections. The molecular mechanisms that …
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Tracking the In Vivo Dynamics of Antigenic Variation in the African Trypanosome
… genes. Although this process, referred to as antigenic variation, is the major mechanism of pathogenesis for T. brucei, the dynamics of VSG expression in T. brucei during an infection are poorly understood. In this thesis, I describe the development of VSG-seq, a method for quantitatively …
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Characterisation of factors that regulate homologous recombination and antigenic variation in Trypanosoma brucei
… mammalian immune response, T. brucei utilises antigenic variation, which involves switches in the Variant Surface Glycoprotein (VSG) expressed on the cell surface. Such reactions can occur at very high rates (~10-3 switches/cell/generation) and occur primarily by the recombination of VSG genes, …
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Prediction and surveillance of antigenic variation in influenza and SARS-CoV-2 viruses
… has long been a primary model organism for antigenically variable pathogens meaning it can escape immunity acquired through prior exposure by accumulating mutations in the key surface proteins targeted by the immune system (hemagglutinin in the case of influenza). As such, the strain …
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The Role of the Mismatch DNA Repair Protein MutL in Antigenic Variation of the Lyme Disease Spirochete
Antigenic variation is one of the immune evasion mechanisms employed by Borrelia burgdorferi to establish a persistent infection in the host through changes of its outer membrane lipoprotein, VlsE, by recombinational events at the vls locus. A recent study identified a requirement for the …
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The Molecular Characterization of Phosphorylcholine (ChoP) on Histophilus somni Lipooligosaccharide: Contribution of ChoP to Bacterial Virulence and Pathogenesis
… somni virulence factors include expression and antigenic variation of lipooligosaccharide (LOS). Phosphorylcholine (ChoP) is often expressed on H. somni LOS and also undergoes antigenic variation. In this study, five genes that play a role in expression and antigenic variation of ChoP, lic1ABCD …
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Understanding The Mechanism and Extent of Vlse Recombination In Borrelia Burgdorferi Using Next-Generation Sequencing
… agent of Lyme disease, have an elaborate antigenic variation system that involves varying the sequence of <em>vlsE. </em>Previous studies have shown that <em>vlsE</em> antigenic variation occurs continuously inside mammalian hosts. Variation has not been shown previously to occur in<em> in …
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Next-Generation Sequencing of vlsE Recombinational Switching in the Lyme Spirochete
… evade the acquired immune response through antigenic variation. The VlsE antigen is expressed on the spirochete surface during mammalian infection. Virtually unlimited numbers of variants are generated through segmental gene conversion events at the vlsE gene from a series of nearby silent …
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VSG expression in African trypanosomes: Gene silencing, cell cycle and developmental control
… the adaptive immune system, trypanosomes undergo antigenic variation of the variant surface glycoprotein (VSG) coat. The trypanosome genome contains ~2,000 VSG genes, however only a single VSG gene is transcribed with several expression site associated genes (ESAGs) in a polycistronic …
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Streptococcal M protein and human C4BP
Antigenic variation of surface proteins allows microorganisms to evade the immune system of the infected host. This phenomenon represents an apparent paradox, because the variable protein must retain an important function, while its antigenic properties vary extensively. The surface associated M …
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Analysis of the functions and interactions of RAD51 paralogues in Trypanosoma brucei
… brucei evades host acquired immunity by antigenic variation, involving periodic switches in the variant surface glycoprotein (VSG) coat. DNA recombination is critical in this process and a key component of homologous recombination, RAD51, also plays a role in VSG switching. T. brucei …
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Telomere Structure and Shortening in Telomerase-Deficient Trypanosoma brucei: Implications for Anitgenic Variation
… in one of ~20 telomeric Expression Sites (ES). Antigenic variation can occur by transcriptional switching, reciprocal translocations, or duplicative gene conversion events between ES. In recent African isolates, duplicative gene conversion occurs at a high frequency and predominates, but the …
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Characterization of the DMCI and Rad51 homologues and the process of meiosis in trichomonas vaginalis
… these genes could be expressed for use in antigenic variation and in the creation or transfer of resistance genes to other cells. In this study, we induced the expression ofDMCl and Rad51 homologues-key players in Homologous Recombination-using a system of tetracycline induction. We …
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Dynamics of Agglutinin -Like Sequence (Als) Protein Localization on the Surface of Candida Albicans
… adhesin molecules binding to host tissues. Wide variation in expression levels among the ALS genes exists and is related to cell morphology and environmental conditions. ALS1, ALS3, and ALS4 are three of the four most highly expressed ALS genes. This work describes the production and use of …
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Dynamics of Agglutinin-Like Sequence (Als) Protein Localization on the Surface of Candida Albicans
… adhesin molecules binding to host tissues. Wide variation in expression levels among the ALS genes exists and is related to cell morphology and environmental conditions. ALS1, ALS3, and ALS4 are three of the four most highly expressed ALS genes. This work describes the production and use of …
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Expression and behaviour of GPI-anchored surface proteins in trypanosomes
… a population survival strategy based on antigenic variation. However, the vast majority of trypanosome species do not use this strategy and our understanding of the immune evasion strategies used by these species is far less developed. In some species including Trypanosoma theileri, it …
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Studies of the Falls Creek (Texas) strain of relapsing fever spirochetes: Part I. Epidemiological and ecological studies. Part II. Serological studies of the "ticktorium" strain of Borrelia recurrentis var turicatae
… infections in the white rat. There are definite antigenic differences between first attack and first relapse spirochetes. There is evidence, however, that relapse passage, using small amounts (less than 0.01 cc) of blood, may result in the development of certain antigenic strains which were …
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Characterisation of potential Holliday junction resolvases in Trypanosoma brucei
Antigenic variation on the cell surface of the T. brucei is essential for the survival of the parasite in the host immune system. Finding mechanisms to stop variant surface glycoprotein (VSG) switching, and hence the parasites ability to evade the host immune system provides a promising opportunity …
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