Neutralizing IgG4 antibodies are a biomarker of sustained efficacy after peanut oral immunotherapy

BACKGROUND

Clinical efficacy of oral immunotherapy (OIT) has been associated with the induction of blocking antibodies, particularly those capable of disrupting IgE-allergen interactions. Previously, we identified mAbs to Ara h 2 and structurally characterized their epitopes.

OBJECTIVE

We investigated longitudinal changes during OIT in antibody binding to conformational epitopes and correlated the results with isotype and clinical efficacy.

METHODS

We developed an indirect inhibitory ELISA using mAbs to block conformational epitopes on immobilized Ara h 2 from binding to serum immunoglobulins from peanut-allergic patients undergoing OIT. We tested the functional blocking ability of mAbs using passive cutaneous anaphylaxis in mice with humanized FcεRI receptors.

RESULTS

Diverse serum IgE recognition of Ara h 2 conformational epitopes are similar before and after OIT. Optimal inhibition of serum IgE occurs with the combination of 2 neutralizing mAbs (nAbs) recognizing epitopes 1.2 and 3, compared to 2 nonneutralizing mAbs (non-nAbs). After OIT, IgG4 nAbs, but not IgG1 or IgG2 nAbs, increased in sustained compared to transient outcomes. Induction of IgG4 nAbs occurs after OIT only in those with sustained efficacy. Murine passive cutaneous anaphylaxis after sensitization with pooled human sera is significantly inhibited by nAbs compared to non-nAbs.

CONCLUSIONS

Serum IgE conformational epitope diversity remains unchanged during OIT. However, IgG4 nAbs capable of uniquely disrupting IgE-allergen interactions to prevent effector cell activation are selectively induced in OIT-treated individuals with sustained clinical efficacy. Therefore, the induction of neutralizing IgG4 antibodies to Ara h 2 are clinically relevant biomarkers of durable efficacy in OIT.

[Simultaneous EEG-fMRI measurements: insights in applications and challenges]

BACKGROUND

The following article presents an introduction to simultaneous electroencephalography and functional magnetic resonance imaging (EEG-fMRI) measurements which have undergone a huge development during the last few years.

OBJECTIVES

The idea behind combining both non-invasive methods is to join the excellent temporal resolution of EEG (ms) together with the superior spatial resolution of fMRI (mm). In this article the status quo of the method and perspectives regarding multimodal imaging are discussed.

MATERIAL AND METHODS

Simultaneous EEG-fMRI measurements are affected by scanner and cardioballistic artifacts. We present common artifact subtraction methods in order to achieve a feasible data quality and outline what to consider when planning and recording EEG and fMRI simultaneously. Moreover, we discuss different analysis strategies.

RESULTS

Combined EEG-fMRI measurements have already increased our knowledge about the underlying relationships between the blood oxygenation level-dependent (BOLD) response and the EEG signal and are applied to answer widespread research questions. Simultaneous measurements are an essential part of multimodal imaging in investigating the underlying processing mechanisms of the brain as well as in advancing our understanding of neuropsychiatric diseases.

CONCLUSIONS

Current developments in multimodal imaging focus on the combination of electrophysiological and MRI parameters within ultra-high field MRI as well as on positron emission tomography (PET) in a trimodal approach.

Continuous, short-interval redox data loggers: verification and setup considerations

Reduction-oxidation or redox potential is typically collected by measuring redox at a single time interval and returning to the electrode to collect subsequent intervals to generate a temporal gradient of changes in redox. Typically, intervals between sampling are on the scale of hours, days, and weeks, rather than one, five, or 20 minutes due to logistical constraints of collection. These constraints are labor (i.e., constant measurements 24/7) and technology driven (i.e., construction of a unit that is capable of accurately and precisely measuring redox at fine temporal scales). This study describes a continuous, short interval redox data logger that is capable of measuring ±10 mV at minute time intervals. To ensure quality assured and quality controlled data, the redox unit was subjected to tiered verification procedures that documented hardware and probe sensitivity to changes in voltage. Furthermore, the setup was laboratory tested against known mV redox solutions (Zobel, 225 mV), flooded in soil medium over 48 h, and subjected to drying over 48 h. Results highlight and verify the accuracy and precision of the redox probes and hardware for measuring stability and changes in redox. Future research will investigate field operations of redox probes and create spatially and temporally detailed investigations to changes in redox as a result of vegetation, flooding, and management.

Using high throughput sequencing to explore the biodiversity in oral bacterial communities

High throughput sequencing of 16S ribosomal RNA gene amplicons is a cost-effective method for characterization of oral bacterial communities. However, before undertaking large-scale studies, it is necessary to understand the technique-associated limitations and intrinsic variability of the oral ecosystem. In this work we evaluated bias in species representation using an in vitro-assembled mock community of oral bacteria. We then characterized the bacterial communities in saliva and buccal mucosa of five healthy subjects to investigate the power of high throughput sequencing in revealing their diversity and biogeography patterns. Mock community analysis showed primer and DNA isolation biases and an overestimation of diversity that was reduced after eliminating singleton operational taxonomic units (OTUs). Sequencing of salivary and mucosal communities found a total of 455 OTUs (0.3% dissimilarity) with only 78 of these present in all subjects. We demonstrate that this variability was partly the result of incomplete richness coverage even at great sequencing depths, and so comparing communities by their structure was more effective than comparisons based solely on membership. With respect to oral biogeography, we found inter-subject variability in community structure was lower than site differences between salivary and mucosal communities within subjects. These differences were evident at very low sequencing depths and were mostly caused by the abundance of Streptococcus mitis and Gemella haemolysans in mucosa. In summary, we present an experimental and data analysis framework that will facilitate design and interpretation of pyrosequencing-based studies. Despite challenges associated with this technique, we demonstrate its power for evaluation of oral diversity and biogeography patterns.

High Pressure Liquid Chromatographic Determination of Nitrogen Derived from Urea and Water-Soluble Methylene Ureas in Urea Formaldehyde Fertilizers: Collaborative Study

A melhod for measuring nitrogen derived from urea, melhylenediurea (MDU), and dimethylenetriurea (DMTU) was tested by 9 collaborators. Collaborators made single determinations on 2 separate days on 5 sets of paired samples. Samples were extracted with water, filtered, and analyzed after high pressure liquid chromatographic separation on a C-8 or C-18 bonded silica column, using a refractive index detector. Peak heights compared to external standard of each component were used for quantitation. Mean coefficients of variation for the completed study were 3.24% for urea, 3.48% for MDU, and 6.56% for DMTU. The method has been adopted official first action.

Glandular epithelial induction by embryonic mesenchyme in adult bladder epithelium of BALB/c mice

Tissue recombinants prepared with epithelium of the urinary bladder of adult mice and mesenchyme of the embryonic urogenital sinus were grown as renal capsular grafts in adult male hosts. Under these conditions the bladder epithelium, which is derived embryologically from the urogenital sinus, was induced to form prostate-like acini. The relevance of this observation to McNeal's (1978) hypothesis, that the formation of prostatic acini during the development of human benign prostatic hyperplasia may be a reexpression of the embryonic inductive capacity of the prostatic stroma, is discussed.