1,720,965 research outputs found
The role of Interleukin-4 induced gene 1 (IL-4i1) in allergic asthma and atopic dermatitis
Get PDFAllergies are described as an unnecessary immune response to non-harmful substances known as allergens. Both allergic asthma and atopic dermatitis (AD) are said to be induced by elevated levels of immunoglobulin E (IgE) and T helper 2 (Th2) immune cells and inflammatory associated cells such as eosinophils, mast, and basophils. Globally, asthma is affecting more than 300 million people and is characterized by chronic airway inflammation, reversible airflow limitation, and airway hyperreactivity. AD is affecting approximately 15%-20% of the pediatric population and 7%-10% of adults in the world and is characterized by dysregulation of skin barrier and immunity, eczematous lesions, dry and itchy skin. Dysfunctional tolerogenic immune response to these innocuous allergens has been described as a leading cause of allergic disease pathogenesis. Interleukin-4 induced gene 1 (IL-4i1) is a secreted L-amino acid oxidase enzyme mainly expressed by antigen-presenting cells (APCs) and upon activation by IL-4 and CD40, can be induced in B lymphocytes. IL-4i1 converts phenylalanine into phenylpyruvate, ammonia, and hydrogen peroxide which can induce effector T cells suppression by inhibiting their activation, proliferation, and cytokine production while promoting a regulatory T cell (Tregs) arm. The contribution of IL-4i1 and its immunoregulatory potential has not yet been explored in allergic asthma and atopic dermatitis. Thus, we proposed to investigate the role of IL-4i1 during allergic asthma and atopic dermatitis using acute mouse models. Female mice of 8-12 weeks old either sufficient (IL-4i1+/+) or deficient of IL4i1 (IL-4i1-/- ) backcrossed to BALB/c genetic background were used in this study. For induction of allergic asthma, a high dose (100µg/per mouse) of house dust mite (HDM) was used in sensitizing mice intratracheally at day 0 and challenged at day 7 to 11 intranasally under anaesthesia. To assess the development of asthma features, we measured lung function on day 14 and collected blood for ELISAs, mediastinal lymph nodes, and lung tissues for FACS and RNA. For induction of AD, a skin irritant vitamin D3 analog (MC903) was used to topically sensitize shaved mice (IL-4i1+/+ or IL-4i1-/- ) for 9 consecutive days. We assessed disease score and skin inflammation at day 10 and collected blood, inguinal lymph nodes, and skin for ELISAs, FACS, RNA, and histology analysis. In both disease models, we saw a significant reduction in total IgE in IL-4i1- deficient mice compared to IL-4i1+/+ littermate controls. A significant upregulation of Th2 cytokines and increased eosinophilia was seen in IL-4i1 deficient mice in the allergic asthma model with no changes in airway hyperresponsiveness. In AD model, we observed a protective effect in the absence of IL-4i1, which was demonstrated by no changes in body weight a reduced skin epidermal thickness, and reduced systemic type 2 cytokines, TSLP, IL-5, and IL-13 producing CD8 T cells. Furthermore, type 2 alarmin, TSLP was reduced at disease site. These results suggest a dichotomy of IL4i1 in regulation of type 2 immune responses depending on disease site. This data further suggests that IL4i1 may be a potential target for therapy against these diseases. Studies are currently underway to understand how IL-4i1 is induced and how it regulates downstream effector molecules and how these target molecules can be inhibited
Investigation of the molecular adjuvant potential of Trypanosoma congolense BiP/HSP70 using congopain as model antigen.
Get PDFThesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.African animal trypanosomiasis is a major threat to African agriculture causing a loss estimated to 4.5 billion US$ per annum. Trypanosoma congolense is the major causative agent in African animal trypanosomiasis and is transmitted by tsetse flies of the Glossina spp. Congopain, a major cathepsin L-like cysteine peptidase in T. congolense is associated with trypanotolerance in N‘Dama cattle and is a target for an anti-disease vaccine. It is suggested that trypanotolerant cattle control the disease by antibody mediated neutralisation of congopain, and that immunisation of cattle against congopain can mimic trypanotolerance resulting in minimised disease pathology. Susceptible cattle immunised with recombinant catalytic domain of congopain, C2, produced high levels of anti-congopain IgG specific antibodies against congopain, maintained weight and exhibited less severe anaemia. However, there was no effect on the establishment of T. congolense infection and acute anaemia development in trypanosusceptible cattle. It has been suggested that failure of congopain to give full protection of the host may be due to poor presentation to the immune system by conventional adjuvants used in previous studies.
The aim of the present study was to improve the presentation of the catalytic domain of congopain (C2) to the immune system, by linking it to the proposed molecular adjuvant, BiP, an ER localised HSP70. A further aim was to localise the domain(s) of BiP where the adjuvant properties reside. BiP consists of an ATPase domain (ATPD), a peptide binding domain (PBD) and a C-terminal domain (C-term). Consequently, BiP69, BiP69 lacking the C-terminal domain (BiP60), BiP coding fragments (ATPD, PBD and C-term) and the C2 coding sequence were amplified by PCR from either genomic T. congolense DNA or plasmid DNA. The PCR products were each sub-cloned into a pTZ57RT vector, and C2 cloned into a pET-28a expression vector. The BiP coding fragments were inserted into the recombinant pET-28a-C2 vector, resulting in pET-28a-BiP69-C2, pET-28a-BiP60-C2, pET-28a-ATPD-C2, pET-28a-PBD-C2 and pET-28a-C-term-C2 coding chimeras. The fusion proteins were expressed in an E. coli system as insoluble inclusion bodies at the expected sizes of 96 kDa (BiP69-C2), 88 kDa (BiP60-C2), 47 kDa (PBD-C2), 34 kDa (C-term-C2) and 27 kDa (C2). However, the ATPD-C2 fusion protein was expressed at a larger and smaller size in different attempts. Protein expression was confirmed by western blots using anti-BiP antibodies and anti-congopain N-terminal peptide antibodies.
Recombinantly expressed peptide binding domain (PBD)-C2, C-terminus-C2, BiP69-C2, BiP60-C2 chimeras and a BiP69 fusion protein were purified and refolded by a Ni-NTA based one-step on-column refolding method. Bacterial proteins co-purifying with BiP69-C2 and BiP60-C2 chimeras were removed by incubation with 5 mM ATP in the dissociation buffer, but poor yields resulted in using these chimeras as non-pure proteins. Immunisation of Balb/c mice with the BiP69-C2 fusion protein chimera induced a higher antibody response to C2 compared to immunisation with the BiP69/C2 mixture or with C2 in Adjuphos/Quil A. BiP69-C2 and PBD-C2 chimeras and BiP69/C2 mixture induced a robust antibody response to BiP69, but no correlation could be made with the contribution to control of parasitemia and disease induced pathology. Mice immunised with BiP69-C2 and PBD-C2 chimeras showed a better booster effect of T. congolense infection with higher anti-C2 antibody stimulation compared to control groups. Immunisation did not change the establishment of T. congolense infection and anaemia development in most immunised groups. However, mice immunised with the BiP69/C2 mixture and with the PBD-C2 chimera produced anti-C2 antibodies possible contributing to clearing parasites 10 days and 16 days earlier respectively, than mice immunised with BiP69-C2, C-term-C2 and BiP60-C2 chimeras and PBS, C2 and C2 in Adjuphos/Quil A control groups and showed no clinical symptoms of the disease. There was no significant difference in percentage mice survival between BiP-C2 chimera immunised mice and control groups immunised with C2 alone or with a mixture of Adjuphos/Quil A or immunised with PBS.
In the present study, it was shown that BiP69 has adjuvant effects when linked to C2 and that its peptide binding domain acts as an adjuvant. It is possible that the removal of the C-terminal domain reduced the adjuvant potency of the peptide binding domain suggesting a prominent role in the adjuvant effect of the BiP molecule. Finding the exact role of the C-terminal domain in the adjuvant effect of BiP would be of utmost interest, and would involve comparing anti-C2 antibody response produced by immunisation with C2 linked to the peptide binding domain with or without the C-terminal domain. Future work includes repeating this study in trypanosusceptible cattle to confirm these findings
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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