2,412 research outputs found
Characterisation and ontogeny of natural killer cells in Xenopus laevis
No full textThe initial aim of the work described in this Thesis was to investigate the lymphoid organ distribution, phenotype and function of the lymphocyte population identified by candidate anti-Xenopus natural killer (NK) cell monoclonal antibodies (mAb's). Since removal of the thymus gland early in larval life (thymectomy) results in the eradication of T-cells and subsequent increase in the proportion of candidate NK cells, thymectomised (Tx) Xenopus were integral in the study of this subset of lymphocytes. Phenotypic and functional studies respectively demonstrated that mAb-defined candidate NK cells do not belong to the B- or T-cell lineage and display cytotoxic activity towards MHC class-Ia-deficient tumour target cells, strengthening the contention that these cells represent the NK subset in Xenopus. The ontogeny of NK cells was investigated in relation to the emergence of the NK cell inhibitory ligand, MHC class-L Splenic NK cells were found to emerge in 6-7 week-old larvae (stage 56-58), which is ≈5 weeks after T- and B-cells become detectable, and some 2 weeks after MHC-Ia is first detected. However, these cells do not appear to be functionally competent until 6 months of age. The expression and ontogeny of recently cloned β2m (the molecule essential for MHC class-I expression) was also briefly investigated. β2m (both RNA and protein) was detectable in all adult tissues and cell lines, even class-I-deficient tumour cells; β2m transcripts were found in 5 week-old larvae that lack MHC class-I. The emergence of NK antigen on a population of T-cells following in vitro stimulation of splenocytes with PMA and calcium ionophore presented the opportunity to biochemically characterise (through immunoprecipitation) the mAb-defined NK antigen. Proteins precipitated using the anti-NK mAb were either surface labelled with biotin, or metabolically labelled with (^35)S. Both techniques resulted in the detection of a protein 55kDa in size
Characterisation of CD8neg and CD8+ human natural killer cell subsets
No full textNK cells are CD3neg CD56+ lymphocytes that constitute about 10-15% of peripheral blood lymphocytes. They have an innate ability to recognise and kill virus infected cells and tumour cells. Their decision to either kill or not to kill a given target is governed by the balance of signals received from inhibitory and activation receptors. NK cells induce target cell death via production of cytotoxic proteins including perforin and granzymes and death ligands expressed on their cell surface. They can be sub-divided according to their surface expression of CD8 antigens into CD8neg and CD8+ subsets. NK cells express CD8αα homodimer unlike those expressed on cytotoxic T lymphocytes, which are CD8αβ heterodimers. The aim of this study was to compare the phenotype and function of the CD8+ and CD8neg NK cell subsets. The results show that CD8+ NK cells comprise about 50% of human resting peripheral NK cells. This percentage increases following IL-2 and IL-15 activation of NK cells because the CD8neg NK cells upregulate expression of the CD8 antigen. The CD8+ subset is more cytotoxic than the CD8neg subset. This was not due to differential expression of NK cell activation or inhibitory receptors, nor due to differences in the expression of perforin and granzymes. Furthermore, both subsets express comparable levels of IFN-γ and TNF-α and degranulated their cytotoxic granules with similar efficiency. Analysis of NK cells from myeloma patients revealed that the two subsets responded differently in different disease stages. Furthermore, Thalidomide treatment increased the frequency of the CD8+ subset, most likely by inducing T cell production of IL-2, which in turn activates NK cells and promotes CD8neg subset development to the more cytotoxic CD8+ subset that facilitates tumour killing
Natural killer cell evolution: cellular and molecular studies on Xenopus
No full textThe presence of natural killer cells at lower evolutionary levels was investigated in the amphibian Xenopus laevis. Chromium release microcytotoxicity assays revealed that fresh splenocytes from early-thymectomised Xenopus displayed significant spontaneous cytotoxicity against allogeneic B(_3)B(_7) thymic tumor cell targets, unlike those from control Xenopus, suggesting that 'NK-like' activity is greater in thymectomised (T cell-deficient) animals. Addition of Concanavalin A- derived active supernatants to splenocytes from a thymectomised animal caused a significant increase in cytolytic activity, but had no effect on cells from a control animal. This finding of enhanced cytotoxicity was indicative of lymphokine-activated killing in Xenopus, and supported the concept that tumour cell lysis was mediated by NK - like cells. Attempts were made to enrich the splenocytes for natural killer cells through the selective depletion of other lymphocyte subsets, using the techniques of 'panning’ and 'magnetic bead' separation following monoclonal antibody labelling of cells. On comparison of the two techniques, it was found that both were able to deplete a splenocyte culture of B cells to the same extent, but that magnetic sorting produced far superior results for depletion of T cells. Optimum conditions for magnetic sorting were determined, and used to generate 'purified' populations which were tested for their cytolytic activity. Such preliminary investigations suggested that natural killer like activity in Xenopus is likely to be mediated by a 'non-T / non-B' lymphoid subset. Finally, preliminary work was undertaken into the development of 'phage display' technology for the generation of single chain Fy antibody fragments (ultimately against NK cell surface antigens). PGR amplification of the V(_H) and Kappa chains was attempted on RNA extracted (using various methods) from Carboxypeptidase Y-injected-, B(_3)B(_7)-injected-, and unimmunised mice. Following RNA extraction under optimum conditions. Kappa chains were successfully amplified from experimental spleens, but the heavy chains still require more development
Development of antibody technology to identify natural killer cell surface antigens in Xenopus Laevis
No full textNatural killer (NK)-like lymphocytes have recently been identified in thymectomised (Tx) Xenopus which are capable of spontaneous cytotoxicity towards the MHC- deficient, allogeneic thymus tumour cell line B(_3)B(_7). This Thesis describes attempts to raise antibodies to Xenopus NK cell surface antigens by phage display and hybridoma technology. The phage display technique was optimised for raising antibodies to novel, cellular antigens in a trial run using the Xenopus thymus tumour cell line B(_3)B(_7). Having isolated a phage antibody which was shown by flow cytometry to bind B(_3)B(_7) cells, the technique was then used to try and raise antibodies to Xenopus NK cells. Isolation of an NIC-specific phage antibody was not achieved but phage antibody XL-6 was raised, which bound an antigen on Xenopus lymphocytes. Phage antibody XL-6, and soluble scFv derived from this, were able to identify a putative mature T cell population in the thymus and may be specific for an amphibian homologue of the mammalian leukocyte common antigen CD45. Hybridoma technology was used to isolate three monoclonal antibodies, 1F8, 4D4 and 1G5, which were shown by flow cytometric analysis to identify a putative NK cell population in control and Tx Xenopus. Following immunomagnetic purification, 1F8- positive spleen cells from control and Tx animals were shown to kill the MHC- deficient tumour target B(_3)B(_7), confirming that this antibody was specific for Xenopus NK cells. Western blotting experiments showed that 1F8, 4D4 and 1G5 identified a doublet of protein bands at 72 and 74 kilodaltons in Xenopus gut lymphoid lysates. Initial attempts to isolate cDNA encoding a Xenopus NK cell surface antigen through immunoscreening a xenopus gut cDNA expression library with antibody 1G5 were unsuccessful as was an attempt to clone a Xenopus homologue of the mammalian NK receptor NKR-Pl by PGR
View from Cape Keppel [picture] /
No full textFrom an album of photographs, mainly of Queensland, dated 1868-1872.; Rex Nan Kivell Collection NK 10389/10.; Title from inscription l.l.; Exhibited: Artist in the tropics, Perc Tucker Regional Gallery, Townsville, 1991.; T2687
A Complete map of the Southern Continent [cartographic material] /
No full text"Vol. I: page 325."; A reissue of Thevenot's map of 1663 showing Australia, without east and south coastline to I. St. Pierre. Southern coast of Tasmania, part of west coast of New Zealand and New Guinea shown.; From: Navigantium atque itinerantium bibliotheca ; or A complete collection of voyages and travels / by John Harris. London : s.n., 1744.; Latitude indicated by vertical scale in centre of map. Compass, u.l.; Names in Dutch. Two blocks of text in map are in English.; Title in decorative cartouche, l.l.; Tooley, 241.; Tooley, Pl. 12.; MAP NK 4185 Exhibited: "Mapping our World : Terra incognita to Australia", National Library of Australia, Canberra, 7 November 2013 to 10 March 2014. ANL; Library's copy, NK 4185 is coloured.; Rex Nan Kivell Collection Map NK 4185.Complete collection of voyages and travel
The Adhesion G Protein-Coupled Receptor GPR56/ADGRG1 Is an Inhibitory Receptor on Human NK Cells
No full textSummaryNatural killer (NK) cells possess potent cytotoxic mechanisms that need to be tightly controlled. Here, we explored the regulation and function of GPR56/ADGRG1, an adhesion G protein-coupled receptor implicated in developmental processes and expressed distinctively in mature NK cells. Expression of GPR56 was triggered by Hobit (a homolog of Blimp-1 in T cells) and declined upon cell activation. Through studying NK cells from polymicrogyria patients with disease-causing mutations in ADGRG1, encoding GPR56, and NK-92 cells ectopically expressing the receptor, we found that GPR56 negatively regulates immediate effector functions, including production of inflammatory cytokines and cytolytic proteins, degranulation, and target cell killing. GPR56 pursues this activity by associating with the tetraspanin CD81. We conclude that GPR56 inhibits natural cytotoxicity of human NK cells
[Portion of America] [cartographic material].
No full textSection of a map of America with relief shown pictorially.; Title and author information taken from pencil notes on verso of map.; Rex Nan Kivell Collection Map NK 10432
Bespoke Tailoring: the luxury and heritage we can afford
No full textThis paper investigates the conflict between hand crafted bespoke tailoring and computerised mass market tailoring in the UK, in order to assess the overall place for this traditional technique within fashion design. It supports a need for retaining the heritage of traditional skills practiced in bespoke tailoring and justifies this as a luxury the consumer can and should afford. The research emphasises the pedagogic approach to the delivery and understanding of tailoring technology in the fashion design courses at University of Huddersfield. This understanding underpins the student’s perception of pattern cutting, fit, sizing, proportion and an overall approach to making clothes. Fashion tutors at Huddersfield believe that when students are taught to appreciate the luxury, heritage and skill of bespoke tailoring, it equips them with the confidence and expertise to create any type of garment.
The luxury of the traditional tailoring process is in the time, craft and experience instilled into each garment. A bespoke tailor is a sculptor whose medium is cloth. He moulds a shell out of this cloth that refines and accentuates the human form. It is a unique service in which the client’s individual measurements are applied to the creation of a garment made to their exact size specifications. Particular attention is given to the detail, quality and excellence in the work. Bespoke tailoring as a fashionable look had a revived popularity in the late 1990’s and early 2000’s. Many fashion designers at the cutting edge of the fashion industry such as Vivienne Westwood and Alexander McQueen pushed the look of tailoring and the craft traditions of bespoke to the forefront of directional fashion, which in turn provoked a resurgence of interest in the craft. Holding court in a 1998 interview in English Vogue, Vivienne Westwood said;
‘I don’t understand this desperate need to always move forward. To strive for the new is the most conformist thing you can do. Everyone can tell you about what is new and clever, but no-one can tell you what is good! There is a myth that the past is irrelevant, that progress is the only thing.’ (Westwood, 1998)
The paper analyses how the bespoke industry considers the incorporation of new and computerised technology. In so doing, it considers how the fashion industry could determine the future of tailoring. This could either be through contemporary fashion’s emphasis on the idiom as a look, or in the vast advances in technological development that could enhance it, in order to make bespoke more widely available.
The paper culminates by considering realistic strategies as the technology within an accessible and computerised mass market industry grows and develops. It highlights that its promotion as a luxurious craft with an un-rivalled heritage, at the cutting edge of the industry, could be the key to the customer buying into its continued existence
In Vivo IFN-γ Secretion by NK Cells in Response to Salmonella Typhimurium Requires NLRC4 Inflammasomes
No full textabstract: Natural killer (NK) cells are a critical part of the innate immune defense against viral infections and for the control of tumors. Much less is known about how NK cells contribute to anti-bacterial immunity. NK cell-produced interferon gamma (IFN-γ) contributes to the control of early exponential replication of bacterial pathogens, however the regulation of these events remains poorly resolved. Using a mouse model of invasive Salmonellosis, here we report that the activation of the intracellular danger sensor NLRC4 by Salmonella-derived flagellin within CD11c[superscript +] cells regulates early IFN-γ secretion by NK cells through the provision of interleukin 18 (IL-18), independently of Toll-like receptor (TLR)-signaling. Although IL18-signalling deficient NK cells improved host protection during S. Typhimurium infection, this increased resistance was inferior to that provided by wild-type NK cells. These findings suggest that although NLRC4 inflammasome-driven secretion of IL18 serves as a potent activator of NK cell mediated IFN-γ secretion, IL18-independent NK cell-mediated mechanisms of IFN-γ secretion contribute to in vivo control of Salmonella replication.The article is published at http://journals.plos.org/plosone/article?id=10.1371/journal.pone.009741
- …
