Interleukin-4 (IL-4) enhances and soluble interleukin-4 receptor (sIL-4R) inhibits histamine release from peripheral blood basophils and mast cells in vitro and in vivo

The aim of the study was to analyse the effect of interleukin-4 (IL-4) on allergen and anti-IgE mediated histamine release from basophils and human skin mast cells and to assess whether soluble recombinant interleukin-4 receptor (sIL4R) can inhibit these effects. Anti-IgE stimulated histamine release from peripheral blood basophils and mast cells of atopic donors was enhanced after preincubation with IL-4, whereas after preincubation with sIL-4R it was inhibited. These effects were even more pronounced when samples were stimulated with a clinically relevant allergen. In IL-4 preincubated skin mast cells, there was a similar enhancement of anti-IgE stimulated histamine release, which could again be inhibited by sIL-4R. The effects of IL-4 and sIL4R were dose- and time-dependent. Mice sensitized to ovalbumin and treated with soluble recombinant murine sIL-4R showed significantly reduced immediate-type cutaneous hypersensitivity responses compared with untreated mice. These in vivo effects were IgE independent, since there were no significant differences in total and allergen specific IgE/IgG1 antibody titres between treated and untreated mice. This indicates that IL4 exerts priming effects on histamine release by effector cells of the allergic response and that these effects are potently antagonized by soluble IL-4R both in vitro and in vivo

Suppression of BCL6 Function by HDAC Inhibitor Mediated Acetylation and Chromatin Modification Enhances BET Inhibitor Effects in B-cell Lymphoma Cells

Multiple genetic aberrations in the regulation of BCL6, including in acetyltransferase genes, occur in clinically aggressive B-cell lymphomas and lead to higher expression levels and activity of this transcriptional repressor. BCL6 is, therefore, an attractive target for therapy in aggressive lymphomas. In this study romidepsin, a potent histone deacetylase inhibitor (HDACi), induced apoptosis and cell cycle arrest in Burkitt and diffuse large B-cell lymphoma cell lines, which are model cells for studying the mechanism of action of BCL6. Romidepsin caused BCL6 acetylation at early timepoints inhibiting its function, while at later timepoints BCL6 expression was reduced and target gene expression increased due to chromatin modification. MYC contributes to poor prognosis in aggressive lymphoma. MYC function is reduced by inhibition of chromatin readers of the bromodomain and extra-terminal repeat (BET) family, which includes BRD4. The novel combination of romidepsin and JQ1, a BRD4 inhibitor was investigated and showed synergy. Collectively we suggest that the combination of HDACi and BRD4i should be pursued in further pre-clinical testing.Funding: The work was supported by grants SAF2014-53526-R and SAF2017-88026-R from MINECO, Spanish Government, to M.D.D. and J.L. (partially funded by FEDER program from European Union). M.G.C. was recipient of a “Marcos Fernández” fellowship from Leukemia and Lymphoma foundation. L.G.G. was recipient of a FPI fellowship from Spanish Government

Evaluatie van de Pertussis Serological Potency Test ter vervanging van de muisbeschermings test middels een internationale ringstudie

De Pertussis Serological Potency Test (PSPT) is gebaseerd op het in vitro meten van de humorale afweerrespons tegen Bordetella pertussis bacterikn en ontwikkeld als een alternatief voor de muisbeschermingstest (MBT) voor het kinkhoest "whole cell" vaccin (WCV). Middels een internationale ringstudie van beperkte omvang (5 laboratoria) is de relevantie en betrouwbaarheid van de PSPT bestudeerd. De studie is opgedeeld in drie verschillende fases met elk hun eigen doelstelling. De pre-fase is toegevoegd als trainingssessie voor de participanten, die geen ervaring hadden met de antilichaam detectie assay, de 18323-whole cell ELISA (18323-WCE). Zestien serumpools zijn op 5 verschillende dagen getest, hetgeen resulteerde in significante verschillen in de extinctie-waarden en antilichaamconcentraties tussen de laboratoria. Tijdens de fase I studie werd de herhaalbaarheid (plaat en dagverschil) en de reproduceerbaarheid (verschil tussen laboratoria) bestudeerd. De gewenste precisie van minder dan 20% niet altijd werd gehaald en significante verschillen in antilichaamconcentraties werden gedurende de hele fase I-studie gevonden. Echter, de rangschikkingen van de serumpools op basis van de antilichaamconcentraties van de laboratoria komen goed met elkaar overeen, waardoor een betrouwbare potency bepaling van WCV's in de PSPT gewaarborgd lijkt. In fase II werd de PSPT met MBT vergeleken. Door vier van de vijf participanten werden 4 WCV's van verschillende herkomst tweemaal in beide modellen getest. De gemiddelde antilichaamconcentratie per vaccindosis in de PSPT, maar ook de overleving van de muizen in de MBT verschilde significant binnen en tussen de laboratoria. Desalniettemin, zijn er voor de vaccins in beide werkzaamheidstesten geen significante verschillen in de potencies gevonden. Met behulp van de c2-test is aangetoond dat de PSPT en de MBT goed correleren zowel binnen als tussen de laboratoria. Echter, de PSPT is beter reproduceerbaar en verlaagt de kans op hertesten van het vaccin omdat de betrouwbaarheidsintervallen kleiner zijn dan bij de MBT. Met deze studie hebben we aangetoond dat de PSPT een valide test is voor het bepalen van de werkzaamheid van kinkhoest WCV's, afkomstig van verschillende producenten.The Pertussis Serological Potency Test (PSPT) - based on in vitro assessment of the humoral immune response against Bordetella pertussis - was developed as an alternative for the Mouse Protection Test (MPT). A small-scale collaborative study was carried out in five laboratories to evaluate the relevance and reliability of the PSPT. The study has been divided into three separate phases, each with its own objective. A pre-phase study of the antibody detection assay, the 18323-whole cell ELISA (WCE) was included for training purposes. Sixteen serum samples were tested on 5 different days, resulting in significant differences in absorbance and antibody concentrations between the laboratories. In the Phase I study, the intra-assay, inter-assay and inter-laboratory precision of the 18323-WCE was assessed. The 5 participants assayed sixteen other serum pools 5 times on 5 different days. Although a precision of less than 20% was not always established and significant differences in antibody concentrations were found at random throughout the Phase I study, the ranking of the antibody concentrations corresponded well between the laboratories and should warrant a reliable potency estimation of whole cell vaccines (WCV's) in the PSPT. Phase II was a comparative study of the PSPT and the MPT to evaluate the implementation of the PSPT, to demonstrate correlation and to compare the reproducibility and reliability of both tests. Four out of the 5 participant have tested 4 different WCV's twice in the PSPT and the MPT. The mean antibody concentrations per vaccine dose in the PSPT and the survival of mice in the MPT differed significantly within and between the laboratories. Nevertheless, the potencies of the vaccines under test estimated in both test models did not differ significantly (p > 0.05). The PSPT and MPT correlated well in a c2-test of homogeneity within and between the laboratories. The potencies were almost similar (overall ratio = 0.877), but the PSPT is more reproducible and reduces the chance of re-testing due to the smaller 95% confidence intervals. In conclusion, the PSPT is a valid model to estimate the potencies of pertussis WCV's of different manufacturers.Platform voor Alternatieven van Dierproeven (PAD 94-26