Shiga Toxin Binding to Glycolipids and Glycans

Background: Immunologically distinct forms of Shiga toxin (Stx1 and Stx2) display different potencies and disease outcomes, likely due to differences in host cell binding. The glycolipid globotriaosylceramide (Gb3) has been reported to be the receptor for both toxins. While there is considerable data to suggest that Gb3 can bind Stx1, binding of Stx2 to Gb3 is variable. Methodology: We used isothermal titration calorimetry (ITC) and enzyme-linked immunosorbent assay (ELISA) to examine binding of Stx1 and Stx2 to various glycans, glycosphingolipids, and glycosphingolipid mixtures in the presence or absence of membrane components, phosphatidylcholine, and cholesterol. We have also assessed the ability of glycolipids mixtures to neutralize Stx-mediated inhibition of protein synthesis in Vero kidney cells. Results: By ITC, Stx1 bound both Pk (the trisaccharide on Gb3) and P (the tetrasaccharide on globotetraosylceramide, Gb4), while Stx2 did not bind to either glycan. Binding to neutral glycolipids individually and in combination was assessed by ELISA. Stx1 bound to glycolipids Gb3 and Gb4, and Gb3 mixed with other neural glycolipids, while Stx2 only bound to Gb3 mixtures. In the presence of phosphatidylcholine and cholesterol, both Stx1 and Stx2 bound well to Gb3 or Gb4 alone or mixed with other neutral glycolipids. Pre-incubation with Gb3 in the presence of phosphatidylcholine and cholesterol neutralized Stx1, but not Stx2 toxicity to Vero cells

The Severe Paediatric Asthma Collaborative in Europe (SPACE) ERS clinical research collaboration: enhancing participation of children with asthma in therapeutic trials of new biologics and receptor blockers

Asthma is one of the most common chronic diseases of childhood. Fortunately, most children with asthma have a mild or moderate form of the disease [1], and symptom control can be achieved by ensuring adequate provision of care and continuously addressing the basics in asthma management through shared decision-making with patients and their families. However, asthma remains difficult to treat for a small proportion of children who may be symptomatic despite aggressive maintenance therapy and after management issues like adherence to treatment have been addressed [2, 3]. The expression “a small proportion” is anecdotal, since estimating the “true” prevalence of severe asthma in childhood has proved challenging. Epidemiological research on this topic is hampered by the heterogeneity in criteria used to define and classify paediatric severe asthma, as well as the scarcity of validated monitoring and outcome-assessment tools [2, 3]. Moreover, even with the adoption of a more standardised and internationally acknowledged definition, an accurate estimate of severe asthma prevalence should be based on very large population cohort studies including information on therapy not only by questionnaires but also from pharmacy-dispensed prescriptions

Biologicals in childhood severe asthma: the European PERMEABLE survey on the status quo

Introduction: Severe asthma is a rare disease in children, for which three biologicals, anti-immunoglobulin E, anti-interleukin-5 and anti-IL4RA antibodies, are available in European countries. While global guidelines exist on who should receive biologicals, knowledge is lacking on how those guidelines are implemented in real life and which unmet needs exist in the field. In this survey, we aimed to investigate the status quo and identify open questions in biological therapy of childhood asthma across Europe. Methods: Structured interviews regarding experience with biologicals, regulations on access to the different treatment options, drug selection, therapy success and discontinuation of therapy were performed. Content analysis was used to analyse data. Results: We interviewed 37 experts from 25 European countries and Turkey and found a considerable range in the number of children treated with biologicals per centre. All participating countries provide public access to at least one biological. Most countries allow different medical disciplines to prescribe biologicals to children with asthma, and only a few restrict therapy to specialised centres. We observed significant variation in the time point at which treatment success is assessed, in therapy duration and in the success rate of discontinuation. Most participating centres intend to apply a personalised medicine approach in the future to match patients a priori to available biologicals. Conclusion: Substantial differences exist in the management of childhood severe asthma across Europe, and the need for further studies on biomarkers supporting selection of biologicals, on criteria to assess therapy response and on how/when to end therapy in stable patients is evident