1,721,613 research outputs found
ETEC vaccination in pigs
No full textEnterotoxigenic Escherichia coli (ETEC) remain an important cause of neonatal and post-weaning diarrhoea in pigs. In general, neonatal infections can be prevented effectively by passive colostral and lactogenic immunity obtained by vaccination of the sow. In this respect, several maternal vaccines are on the market. These are applied mainly parenterally in the pregnant sow. However at weaning, lactogenic protection disappears. Strains involved in post-weaning diarrhoea mostly express F4 or F18 fimbriae. These fimbriae are important virulence factors since they allow the bacteria to bind to specific receptors on small intestinal enterocytes, resulting in colonization and subsequently the secretion of enterotoxins causing diarrhoea. Consequently, an active mucosal immunity, in which the local production of F4- and/or F18-specific sIgA plays an important role, is required to protect pigs against post-weaning diarrhoea. This review aims to give an overview of the immunization strategies applied in the pig model to prevent post-weaning diarrhoea caused by F4- and/or F18- positive ETEC in pigs. These include the use of oral live and subunit vaccines, encapsulation strategies and parenteral immunization.status: Publishe
Optimization of a small intestinal segment perfusion model for heat-stable enterotoxin A induced secretion in pigs
No full textMucosal priming of the murine immune system against enterohemorrhagic Escherichia coli O157:H7 using Lactococcus lactis expressing the type III secretion system protein EspB
No full textThe Fcγ receptor expression profile on porcine dendritic cells depends on the nature of the stimulus
No full textNowadays, vaccine research focuses on the development and implementation of subunit vaccines into existing or future vaccination platforms. However, recombinant proteins are often poor immunogens, necessitating adjuvants to activate and direct the immune response. Alternatively, the immunogenicity of antigens can be enhanced by targeting antigens to Fcγ receptors on antigen-presenting cells and as dendritic cells (DCs) are the most potent antigen-presenting cells, orchestrating innate and adaptive immune responses, they are attractive for this selective targeting of vaccine antigens. However, DCs express both inhibitory and activating Fcγ receptors and regulating DC function is pivotal to ensure the induction of effective immune responses and to prevent exaggerated immune responses causing inflammation. Previously, we demonstrated that immature porcine MoDC express FcγRII and FcγRIII on their cell surface, which mediate a functional DC maturation upon activation through immune complexes. In the present study, we clearly demonstrate that immune complexes are primarily internalised via FcγRIII, resulting in DC maturation and that depending on the DC maturation stimulus the FcγR expression profile is differentially regulated. These results could not only expedite the development of FcγR-targeting based vaccines, but also provide insights into FcγR-mediated autoimmune diseases.sponsorship: B. Devriendt acknowledges the IWT-Vlaanderen and Ugent (BOF-GOA) for their financial support. E. Cox acknowledges the FWO-Vlaanderen for funding. We thank K. Seminck for her technical support. Dr. Inumaru is acknowledged for kindly providing the rpGM-CSF. (IWT-Vlaanderen, Ugent (BOF-GOA), FWO-Vlaanderen)status: Publishe
Maltose-binding protein is a potential carrier for oral immunizations
Full text linkMaltose binding protein (MBP) is often fused to a relevant protein to improve its yield and facilitate its purification, but MBP can also enhance the immunogenicity of the fused proteins. Recent data suggest that MBP may potentiate antigen-presenting functions in immunized animals by providing intrinsic maturation stimuli to dendritic cells through TLR4. The aim of this study was to examine if an MBP-specific immune response can be elicited by oral administration of MBP. Therefore, in a first experiment the MBP specific immune response was analyzed after oral immunization with MBP or MBP+CT to piglets and both the systemic and mucosal immune responses were examined Although no high systemic response was observed in the MBP-group, a local mucosal IgM MBP-specific response in the jejunal Peyer's patches was observed. In the second experiment MBPFedF was orally administered to piglets. A significant systemic response against MBP and a weak response against FedF were found after oral administration of MBPFedF+CT. Also the presence of MBP-specific IgA ASC in the lamina propria indicates that a local intestinal immune response against MBP was induced. Our data suggests that MBP can cross the epithelial barrier reaching the gut-associated lymphoid tissue after oral administration to pigs, which implicates that MBP could act as a carrier and delivery system for fused proteins to target the vaccine antigens to intestinal immune cells.sponsorship: This work was supported by the Research Fund of the UGent, by the 'FWO-Flanders' and by the 'Institute for the Promotion of Innovation through Science and Technology in Flanders' (IWT-Vlaanderen). (UGent, FWO-Flanders, 'Institute for the Promotion of Innovation through Science and Technology in Flanders' (IWT-Vlaanderen))status: Publishe
Differentiation of F4 receptor profiles in pigs based on their mucin 4 polymorphism, responsiveness to oral F4 immunization and in vitro binding of F4 to villi
No full textGoing Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
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