512 research outputs found

    Qualitative and quantitative aspects of human igg subclass responses with special reference to a common microorganism, moraxella (branhamella) catarrhalis

    Get PDF
    Although much is known of the physico-chemical characteristics of the IgG subclasses, their specific biological function remains poorly understood. The consequence of either absence or low levels of one or more subclasses is still unclear. In an effort to document the clinical manifestation of IgG subclass deficiency in a paediatric population, a clinical study of children presenting with IgG subclass deficiency was undertaken. 42% of the 232 children reviewed presented with frequent infections, 17% presented with allergy and 13% presented with a combination of infection and allergy. No clear trends emerged relating the deficiency of a particular subclass with any given clinical manifestation. Since healthy individuals may have low levels or a complete absence of certain IgG subclasses the functional study of IgG subclasses needs to go beyond their quantitative estimation. It is known that individuals with normal IgG subclass levels may nevertheless suffer from frequent infection due to an inability to respond in an isotype appropriate way to carbohydrate antigens. This phenomenon suggests that an appropriate qualitative assessment is needed to further elucidate IgG subclass function. To this end a study of Moraxella (Branhamella) catarrhalis was undertaken. This bacterium is a ubiquitous gram negative organism which is emerging as an important paediatric pathogen. While healthy children may acquire infection with this organism, in adults it infects predominantly those with compromised immunity or chronic lung disease. To investigate whether this difference might have an immunological basis, a study of the antigens of M. catarrhalis and the age related IgG subclass response to them was undertaken. The surface antigens were defined by the purification of outer membrane proteins (OMPs) followed by SDS-PAGE and immunoblotting. This revealed that the OMPs were targets of human antibody and, furthermore, this recognition differed between the various isotypes with IgG3 recognising an extended range of proteins. By modification of a newly developed enzyme-linked immunosorbent assay (ELISA) the binding affinities of the M.catarrhalis specific IgG subclasses were measured and IgG3 antibodies were found to be of higher affinity than IgGl and IgG2 antibodies, further emphasising the importance of this isotype. An ELISA procedure was also used in an analysis of the age related appearance of IgG subclasses specific for the organism and this revealed that IgG3 antibody was undetectable in children under the age of four yet present in healthy adults and older children. Age related delay in IgG subclass antigen specific responses has previously only been described for carbohydrate antigens and the IgG2 response. Extending these findings to IgG3 regulation and function emphasises the need to acquire antibody response data on both an organism and subclass specific basis

    Mud and a Metaphor

    Get PDF

    Taking Art Personally: Austin, Performatives and Art

    Get PDF
    This paper is an attempt to apply speech act theory to aesthetics. In particular, it purports to be a contribution to reception theory by drawing attention to certain similarities between the contextual structure of performatives and the structure of the reception of art. It hopes to locate the auditor or spectator of artworks in what J. L. Austin calls “the total context” to help explain how certain aspects of artworks can be taken personally, somehow being about and seemingly directed at “me.” It is one way the so-called paradox of fiction can be by-passed by showing how the emotive aspects of artworks are not primarily a matter of our caring about the fictional characters portrayed therein, but directly about members of the viewing or listening audience. Concentrating on the performatives of warnings and threats, this paper details the writings of Austin to help explain why some people can relate to characters or situations presented by art while others are barely moved

    Television sport in the age of screens and content

    Get PDF
    The death of television has been long predicated in the digital age, yet it remains a powerful mediator of live sports. This article focuses on football and examines the implications for the sport of the move to an age of screens and content. These may be large screens in public places or in our homes or those at work or smaller screens carried in the palm of our hands, but what we use them for, how content gets onto those screens, and the implications for sports and sports fans remain compelling questions in the digital age. The article argues that through reflecting on major media sport events such as the FIFA World Cup, we see patterns of continuity in the role played by television as well as evidence of change

    A modal proof theory for final polynomial coalgebras

    Get PDF
    AbstractAn infinitary proof theory is developed for modal logics whose models are coalgebras of polynomial functors on the category of sets. The canonical model method from modal logic is adapted to construct a final coalgebra for any polynomial functor. The states of this final coalgebra are certain “maximal” sets of formulas that have natural syntactic closure properties.The syntax of these logics extends that of previously developed modal languages for polynomial coalgebras by adding formulas that express the “termination” of certain functions induced by transition paths. A completeness theorem is proven for the logic of functors which have the Lindenbaum property that every consistent set of formulas has a maximal extension. This property is shown to hold if the deducibility relation is generated by countably many inference rules.A counter-example to completeness is also given. This is a polynomial functor that is not Lindenbaum: it has an uncountable set of formulas that is deductively consistent but has no maximal extension and is unsatisfiable, even though all of its countable subsets are satisfiable

    Correlates of protection against SARS-CoV-2 infection and COVID-19 disease

    Get PDF
    Antibodies against epitopes in S1 give the most accurate CoP against infection by the SARS-CoV-2 coronavirus. Measurement of those antibodies by neutralization or binding assays both have predictive value, with binding antibody titers giving the highest statistical correlation. However, the protective functions of antibodies are multiple. Antibodies with multiple functions other than neutralization influence efficacy. The role of cellular responses can be discerned with respect to CD4+ T cells and their augmentation of antibodies, and with respect to CD8+ cells with regard to control of viral replication, particularly in the presence of insufficient antibody. More information is needed on mucosal responses

    Effect of Maternally Derived Anti-protein and Anticapsular IgG Antibodies on the Rate of Acquisition of Nasopharyngeal Carriage of Pneumococcus in Newborns.

    Get PDF
    Background: In developing countries, introduction of pneumococcal conjugate vaccine has not eliminated circulation of vaccine serotypes. Vaccinating pregnant mothers to increase antibody concentrations in their newborn infants may reduce the acquisition of pneumococcal carriage and subsequent risk of disease. We explored the efficacy of passive immunity, attributable to anti-protein and anticapsular pneumococcal antibodies, against acquisition of carriage. Methods: We examined the rate of nasopharyngeal acquisition of pneumococci in the first 90 days of life associated with varying anticapsular and anti-protein antibody concentrations in infant cord/maternal venous blood in Kilifi, Kenya. We used multivariable Cox proportional hazard models to estimate continuous functions relating acquisition of nasopharyngeal carriage to the concentration of maternally derived antibody. Results: Cord blood or maternal venous samples were collected from 976 mother-infant pairs. Pneumococci were acquired 561 times during 33,905 person-days of follow-up. Increasing concentrations of anti-protein antibodies were associated with either a reduction (PhtD1, PspAFam2, Spr0096, StkP) or, paradoxically, an increase (CbpA, LytC, PcpA, PiaA, PspAFam1, RrgBT4) in acquisition rate. We observed a nonsignificant reduction in the incidence of homologous carriage acquisition with high concentrations of maternally derived anticapsular antibodies to 5 serotypes (6A, 6B, 14, 19F, and 23F). Conclusion: The protective efficacy of several anti-protein antibodies supports the strategy of maternal vaccination to protect young infants from carriage and invasive disease. We were not able to demonstrate that passive anticapsular antibodies were protective against carriage acquisition at naturally occurring concentrations though it remains possible they may do so at the higher concentrations elicited by vaccination

    Pneumococcal pneumonia.

    Get PDF
    • …
    corecore