Coxackievirus B4 transplacental infection severely disturbs central tolerogenic mechanisms in the fetal thymus

Thymus plays a fundamental role in central tolerance establishment, especially during fetal life, through the generation of self-tolerant T cells. This process consists in T cells education by presenting them tissue-restricted autoantigens promiscuously expressed by thymic epithelial cells (TECs), thus preventing autoimmunity. Thymus infection by Coxsackievirus B (CV-B) during fetal life is supposed to disturb thymic functions and, hence, to be an inducing or accelerating factor in the genesis of autoimmunity. To further investigate this hypothesis, in our current study, we analyzed thymic expression of autoantigens, at the transcriptional and protein level, following in utero infection by CV-B4. mRNA expression levels of Igf2 and Myo7, major autoantigens of pancreas and heart, respectively, were analyzed in whole thymus and in enriched TECs together along with both transcription factors, Aire and Fezf2, involved in autoantigens expression in the thymus. Results show that in utero infection by CV-B4 induces a significant decrease in Igf2 and Myo7 expression at both mRNA and protein level in whole thymus and in enriched TECs as well. Moreover, a correlation between viral load and autoantigens expression can be observed in the whole thymus, indicating a direct effect of in utero infection by CV-B4 on autoantigens expression. Together, these results indicate that an in utero infection of the thymus by CV-B4 may interfere with self-tolerance establishment in TECs by decreasing autoantigen expression at both mRNA and protein level and thereby increase the risk of autoimmunity onset

Essential Oil Composition, Antioxidant, Cytotoxic and Antiviral Activities of Teucrium pseudochamaepitys Growing Spontaneously in Tunisia

The chemical composition, antioxidant, cytotoxic and antiviral activities of the essential oil obtained by hydrodistillation from the aerial parts of Teucrium pseudochamaepitys (Lamiaceae) collected from Zaghouan province of Tunisia are reported. The essential oil was analyzed by gas chromatography equipped with a flame ionization detector (GC-FID) and gas chromatography coupled with mass spectrometry (GC/MS). Thirty-one compounds were identified representing 88.6% of the total essential oil. Hexadecanoic acid was found to be the most abundant component (26.1%) followed by caryophyllene oxide (6.3%), myristicin (4.9%) and α-cubebene (3.9%). The antioxidant capacity of the oil was measured on the basis of the scavenging activity to the stable 2,2-diphenyl-1-picrylhydrazyl (DPPH). The IC50 value of the oil was evaluated as 0.77 mg·mL−1. In addition, the essential oil was found to possess moderate cytotoxic effects on the HEp-2 cell line (50% cytotoxic concentration (CC50) = 653.6 µg·mL−1). The potential antiviral effect was tested against Coxsackievirus B (CV-B), a significant human and mouse pathogen that causes pediatric central nervous system disease, commonly with acute syndromes. The reduction of viral infectivity by the essential oil was measured using a cytopathic (CPE) reduction assay

In vitro antimicrobial, antioxidant and antiviral activities of the essential oil and various extracts of wild (Daucus virgatus (Poir.) Maire) from Tunisia

Essential oils are considered of great efficacity regarding the various beneficial effects on human health. The aim of this study was to analyze the composition and to investigate the antiviral, antioxidant and antimicrobial effects of wild Daucus virgatus (Poir.) Maire from Tunisia. The essential oil obtained by hydrodistillation air-dried D. virgatus in a Clevenger type apparatus was analyzed using gas chromatography and mass spectrometry (GC-FID and GCâ\u80\u93MS). Fifty-two components representing 92.4% of the total constituents were identified. Methyl eugenol (33.0%) and β-bisabolene (13.2%) were the most predominant components. The antibacterial and antifungal activities against the pathogens: Pseudomonas aeruginosa, Bacillus subtilis, Bacillus anthracis, Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis and Candida albicans were investigated using the agar diffusion and broth microdilution methods. The lowest minimum inhibitory concentration was 625 μg mLâ\u88\u921 against both B. subtilis and C. albicans. Investigation of the in vitro antiviral activity of the essential oil, ethylacetate and methanolic extracts was tested against Coxsackievirus B (CV-B), a small nonenveloped single-stranded and positive-sense RNA virus of the Picornaviridae family that produce central nervous system disease frequently with acute syndromes. The reduction of viral infectivity of the extracts was determined by the plaque reduction assay. The cytotoxicity test demonstrated moderate cytotoxic effects of the crude extracts on the HEp-2 cell line. Fifty percent cytotoxic concentrations (CC50) are 543.35 and 372.7 μg mLâ\u88\u921 for ethylacetate and methanol respectively. Furthermore, ethylacetate and methanol extracts exhibited significant inhibitory effects against CV-B4 virus with IC50 vales of 98.16 and 60.08 μg mLâ\u88\u921 respectively