Progressive Control of Streptococcus agalactiae-Induced Innate Inflammatory Response Is Associated with Time Course Expression of MicroRNA-223 by Neutrophils.

Group B streptococcus (GBS) is a human-pathogenic bacterium inducing a strong inflammatory response that may be detrimental for host tissues if not finely regulated. The inflammatory response can be modulated by different molecular mechanisms, among which growing evidence points toward the crucial role of microRNAs (miRNAs). Regarding innate inflammatory response, studies have reported that miR-223 is essential for the control of granulocyte proliferation and activation. Moreover, a number of investigations on miRNA expression profiling performed in various inflammatory settings have revealed that miR-223 is among the top differentially expressed miRNAs. Yet the dynamic pattern of expression of miR-223 in vivo with respect to the evolution of the inflammatory process, especially in microbial infection, remains elusive. In this study, we analyzed the kinetic expression of miR-223 in an inflammatory model of GBS-induced murine pneumonia and looked for correlates with inflammatory markers, including innate cell infiltrates. We found that miR-223 expression is rapidly induced at very early time points (3 to 6 h postinfection [p.i.]) mainly by lung-infiltrating neutrophils. Interestingly, the level of miR-223 accumulating in the lungs remains higher at later stages of infection (24 h and 48 h p.i.), and this correlates with reduced expression of primary inflammatory cytokines and chemokines and with a shift in infiltrating monocyte and macrophage subtypes toward a regulatory phenotype. Transient inhibition of miR-223 by an antagomir resulted in significant increase of CXCL2 expression and partial enhancement of infiltrating neutrophils in GBS-infected lung tissues. This suggests the potential contribution of miR-223 to the resolution phase of GBS-induced acute inflammation.info:eu-repo/semantics/publishe

Sex differences in alveolar macrophages polarization during Streptococcus agalactiae-Induced pneumoniae

Body of clinical and experimental investigations clearly indicate that sex is a contributing factor in the incidence and progression of several infectious diseases. This is particularly observed in respiratory diseases where men present higher morbidity and mortality than in women along the life course. We study the differences between the sexes in the inflammatory response in mice model of pulmonary group B streptococcus (GBS) infection. We found that the dynamics of pulmonary infiltration of alveolar macrophages differ between males and females after intranasal infection of GBS. This is associated with higher local production of the primary pro-inflammatory cytokines IL-1β and TNFα and higher expression of the chemokines CXCL2 and CCL3 in males compared to females. Alveolar macrophages represent a heterogeneous cell population and exhibit remarkable plasticity. In response to distinct micro-environmental stimuli, macrophages can polarize into different cell subtypes: classically activated macrophages (M1), involved in the pro-inflammatory process and in tissue damage, and alternatively activated macrophages (M2), involved in the damping of inflammation and tissue repair. We found that macrophages from GBS-infected male mice expressed higher levels of M1 macrophages markers (iNOS ans CD80). Taken together, our results indicate a differential sex polarization of alveolar macrophages during pulmonary GBS infection, hence suggesting the contribution of M1 macrophages in increased airway inflammation found in male mice.info:eu-repo/semantics/publishe

Development of a Dot-Blot Assay for the Detection of Mould-Specific IgE in the Belgian Population

Background: Data on mould sensitization in the general population are scarce and mostly on Aspergillus fumigatus, Alternaria alternata and Cladosporium herbarum. Objectives: To validate a dot-blot assay for the detection of specific IgE and evaluate the prevalence of mould sensitization in a healthy population. Methods: The dot-blot assay was validated against the CAP test. Sensitization rate to ten common indoor and outdoor mould species in 344 serum samples was calculated. For each serum with more than one reactivity, the “major sensitization” defined as the strongest response against a single mould species was calculated. Results: Intra- and inter-assay variations were both below 20%, and the positivity threshold of the test was of 0.418 kU/L for A. fumigatus. Correlation with CAP results was strong. The overall prevalence of sensitization was 32.8%, and the commonest sensitizations were against A. alternaria, A. flavus and A. niger (around 15%). The most frequent “major reactivities” were against A. niger and A. alternata (20–30%). In 25.1% of the samples, “major reactivities” were directed against a group of moulds commonly found indoor (Penicillium spp. Aspergillus versicolor, Cladosporium sphaerospermum and Cladosporium cladosporioides). Conclusions: The dot-blot assay was validated for the detection of mould-specific IgE. In the general population, sensitization to indoor species was common and accounted for 25% of overall mould sensitizations.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Sex difference in innate inflammatory response and macrophage polarization in Streptococcus agalactiae-induced pneumonia and potential role of microRNA-223-3p

Abstract While number of studies have shown that biological sex is a risk factor in the incidence and severity of infection-induced inflammatory diseases, the underlying mechanisms are still poorly understood. In this study, we compared the innate inflammatory response in male and female mice with group B streptococcal (GBS)-induced pneumoniae. Although male and female mice displayed similar bacterial burdens, males exhibited more innate inflammatory cytokines and chemokines and a higher proportion of infiltrating monocytes/macrophages. The analysis of the distribution of macrophage subtypes M1 (pro-inflammatory) versus M2 (anti-inflammatory) yielded a higher M1/M2 ratio in infected males compared with females. Given the importance of the chromosome X-linked microRNA-223-3p (miR-223-3p) in modulating the inflammatory process and macrophage polarization, we investigated its potential contribution in sex bias of GBS-induced innate inflammatory response. Knock-down of miR-223-3p with specific antagomiR resulted in increased inflammatory response and higher M1/M2 ratio following GBS infection. Notably, compared to male mice, we detected higher amount of miR-223-3p in macrophages from females that correlated negatively with M1 phenotype. These results suggest that differential expression of miR-233-3p may impact macrophage polarization, thereby contributing to fine-tune sex differences in inflammatory response.info:eu-repo/semantics/publishe

Relationship between mold exposure, specific IgE sensitization, and clinical asthma: A case-control study.

Most of the findings related to the noxious effect of mold sensitization on asthma come from investigations based on Alternaria alternata, Cladosporium herbarum, and Aspergillus fumigatus. However, species such as Penicillium spp, Cladosporium sphaerospermum, Cladosporium cladosporioides, or Aspergillus versicolor display a more pronounced indoor tropism, and their potential harmful respiratory effects cannot be neglected.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Induction of in vivo functional Db-restricted cytolytic T cell activity against a putative phosphate transport receptor of Mycobacterium tuberculosis

Using plasmid vaccination with DNA encoding the putative phosphate transport receptor PstS-3 from Mycobacterium tuberculosis and 36 overlapping 20-mer peptides spanning the entire PstS-3 sequence, we determined the immunodominant Th1-type CD4+ T cell epitopes in C57BL/10 mice, as measured by spleen cell IL-2 and IFN-γ production. Furthermore, a potent IFN-γ-inducing, Db-restricted CD8+ epitope was identified using MHC class I mutant B6.C-H-2bm13 mice and intracellular IFN-γ and whole blood CD8+ T cell tetramer staining. Using adoptive transfer of CFSE-labeled, peptide-pulsed syngeneic spleen cells from naive animals into DNA vaccinated or M. tuberculosis-infected recipients, we demonstrated a functional in vivo CTL activity against this Db-restricted PstS-3 epitope. IFN-γ ELISPOT responses to this epitope were also detected in tuberculosis-infected mice. The CD4+ and CD8+ T cell epitopes defined for PstS-3 were completely specific and not recognized in mice vaccinated with either PstS-1 or PstS-2 DNA. The H-2 haplotype exerted a strong influence on immune reactivity to the PstS-3 Ag, and mice of the H-2b, p, and f haplotype produced significant Ab and Th1-type cytokine levels, whereas mice of H-2d, k, r, s, and q haplotype were completely unreactive. Low responsiveness against PstS-3 in MHC class II mutant B6.C-H-2bm12 mice could be overcome by DNA vaccination. IFN-γ-producing CD8+ T cells could also be detected against the Db-restricted epitope in H-2p haplotype mice. These results highlight the potential of DNA vaccination for the induction and characterization of CD4+ and particularly CD8 + T cell responses against mycobacterial Ags.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Investigation of inflammatory and allergic responses to common mold species: Results from in vitro experiments, from a mouse model of asthma, and from a group of asthmatic patients

Most studies on molds focus on Alternaria alternata and Aspergillus fumigatus. Here, we report on inflammatory and allergenic properties of more typical indoor species Aspergillus versicolor, P. chrysogenum, C. cladosporioïdes, and C. sphaerospermum that were compared to A. alternata and A. fumigatus. In a mouse model, after intranasal instillation, A. alternaria, A. versicolor, and C. sphaerospermum induced the early recruitment of neutrophils and the strong expression of inflammatory markers in the bronchoalveolar lavages fluids. A. fumigatus also induced the early accumulation of neutrophils but with lower levels of inflammatory markers. Chronic treatment induced variable response according to species: P. chrysogenum and A. fumigatus appeared strong pro-allergenic inducers compared to A. alternata and C. sphaerospermum while A. versicolor and C. cladosporioides induced a mixed pro-allergenic/pro-inflammatory response. In mold-sensitized asthmatics, mold-specific Immunoglobulin E (IgE) were detected with an in-house dot-blot assay. A. fumigatus and A. alternata were the most frequent sensitizers. Altogether, P. chrysogenum, P. brevicompactum, C. sphaerospermum, and C. cladosporïoides were the “major sensitizer” (defined as the strongest response against a single mold species) for almost 30% of the asthmatics. These results show that, not only A. alternata and A. fumigatus, but also indoor species have strong inflammatory and allergic properties and a harmful potency.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

A randomized, multicentre, open-label phase II proof-of-concept trial investigating the clinical efficacy and safety of the addition of convalescent plasma to the standard of care in patients hospitalized with COVID-19: the Donated Antibodies Working against nCoV (DAWn-Plasma) trial

Abstract Background The COVID-19 pandemic has imposed an enormous burden on health care systems around the world. In the past, the administration of convalescent plasma of patients having recovered from SARS and severe influenza to patients actively having the disease showed promising effects on mortality and appeared safe. Whether or not this also holds true for the novel SARS-CoV-2 virus is currently unknown. Methods DAWn-Plasma is a multicentre nation-wide, randomized, open-label, phase II proof-of-concept clinical trial, evaluating the clinical efficacy and safety of the addition of convalescent plasma to the standard of care in patients hospitalized with COVID-19 in Belgium. Patients hospitalized with a confirmed diagnosis of COVID-19 are eligible when they are symptomatic (i.e. clinical or radiological signs) and have been diagnosed with COVID-19 in the 72 h before study inclusion through a PCR (nasal/nasopharyngeal swab or bronchoalveolar lavage) or a chest-CT scan showing features compatible with COVID-19 in the absence of an alternative diagnosis. Patients are randomized in a 2:1 ratio to either standard of care and convalescent plasma (active treatment group) or standard of care only. The active treatment group receives 2 units of 200 to 250 mL of convalescent plasma within 12 h after randomization, with a second administration of 2 units 24 to 36 h after ending the first administration. The trial aims to include 483 patients and will recruit from 25 centres across Belgium. The primary endpoint is the proportion of patients that require mechanical ventilation or have died at day 15. The main secondary endpoints are clinical status on day 15 and day 30 after randomization, as defined by the WHO Progression 10-point ordinal scale, and safety of the administration of convalescent plasma. Discussion This trial will either provide support or discourage the use of convalescent plasma as an early intervention for the treatment of hospitalized patients with COVID-19 infection. Trial registration ClinicalTrials.gov NCT04429854 .Registered on 12 June 2020 - Retrospectively registered.info:eu-repo/semantics/publishe