Comparative analyses of SARS-CoV-2 binding (IgG, IgM, IgA) and neutralizing antibodies from human serum samples

A newly identified coronavirus, named SARS-CoV-2, emerged in December 2019 in Hubei Province, China, and quickly spread throughout the world; so far, it has caused more than 49.7 million cases of disease and 1,2 million deaths. The diagnosis of SARS-CoV-2 infection is currently based on the detection of viral RNA in nasopharyngeal swabs by means of molecular-based assays, such as real-time RT-PCR. Furthermore, serological assays detecting different classes of antibodies constitute an excellent surveillance strategy for gathering information on the humoral immune response to infection and the spread of the virus through the population. In addition, it can contribute to evaluate the immunogenicity of novel future vaccines and medicines for the treatment and prevention of COVID-19 disease.The aim of this study was to determine SARS-CoV-2-specific antibodies in human serum samples by means of different commercial and in-house ELISA kits, in order to evaluate and compare their results first with one another and then with those yielded by functional assays using wild-type virus. It is important to identify the level of SARS-CoV-2-specific IgM, IgG and IgA antibodies in order to predict human population immunity, possible cross-reactivity with other coronaviruses and to identify potentially infectious subjects.In addition, in a small sub-group of samples, a subtyping IgG ELISA has been performed. Our findings showed a notable statistical correlation between the neutralization titers and the IgG, IgM and IgA ELISA responses against the receptor-binding domain of the spike protein. Thus confirming that antibodies against this portion of the virus spike protein are highly neutralizing and that the ELISA Receptor-Binding Domain-based assay can be used as a valid surrogate for the neutralization assay in laboratories that do not have biosecurity level-3 facilities

Gene expression profile of rat left ventricles reveals persisting changes following chronic mild exercise protocol: implications for cardioprotection

<p>Abstract</p> <p>Background</p> <p>Epidemiological studies showed that physical exercise, specifically moderate lifelong training, is protective against cardiovascular morbidity and mortality. Most experimental work has focused into the effects and molecular mechanisms underlying intense, rather than mild exercise, by exploring the acute effect of training. Our study aims at investigating the cardioprotective effect of mild chronic exercise training and the gene expression profile changes at 48 hrs after the exercise cessation. Rats were trained at mild intensity on a treadmill: 25 m/min, 10%incline, 1 h/day, 3 days/week, 10 weeks; about 60% of the maximum aerobic power. By Affymetrix technology, we investigated the gene expression profile induced by exercise training in the left ventricle (LV) of trained (n = 10) and control (n = 10) rats. Cardioprotection was investigated by ischemia/reperfusion experiments (n = 10 trained vs. n = 10 control rats).</p> <p>Results</p> <p>Mild exercise did not induce cardiac hypertrophy and was cardioprotective as demonstrated by the decreased infarct size (p = 0.02) after ischemia/reperfusion experiments in trained with respect to control rats. Ten genes and 2 gene sets (two pathways) resulted altered in LV of exercised animals with respect to controls. We validated by real-time PCR the increased expression of four genes: similar to C11orf17 protein (RGD1306959), caveolin 3, enolase 3, and hypoxia inducible factor 1 alpha. Moreover, caveolin 3 protein levels were higher in exercised than control rats by immunohistochemistry and Western Blot analysis. Interestingly, the predicted gene similar to C11orf17 protein (RGD1306959) was significantly increased by exercise. This gene has a high homology with the human C11orf17 (alias: protein kinase-A interacting protein 1 or breast cancer associated gene 3). This is the first evidence that this gene is involved in the response to the exercise training.</p> <p>Conclusion</p> <p>Our data indicated that few, but significant, genes characterize the gene expression profile of the rat LV, when examined 48 hrs since the last training section and that mild exercise training determines cardioprotection without the induction of hypertrophy.</p

A model of anti-angiogenesis: differential transcriptosome profiling of microvascular endothelial cells from diffuse systemic sclerosis patients

The objective of this work was to identify genes involved in impaired angiogenesis by comparing the transcriptosomes of microvascular endothelial cells from normal subjects and patients affected by systemic sclerosis (SSc), as a unique human model disease characterized by insufficient angiogenesis. Total RNAs, prepared from skin endothelial cells of clinically healthy subjects and SSc patients affected by the diffuse form of the disease, were pooled, labeled with fluorochromes, and hybridized to 14,000 70 mer oligonucleotide microarrays. Genes were analyzed based on gene expression levels and categorized into different functional groups based on the description of the Gene Ontology (GO) consortium to identify statistically significant terms. Quantitative PCR was used to validate the array results. After data processing and application of the filtering criteria, the analyzable features numbered 6,724. About 3% of analyzable transcripts (199) were differentially expressed, 141 more abundantly and 58 less abundantly in SSc endothelial cells. Surprisingly, SSc endothelial cells over-express pro-angiogenic transcripts, but also show up-regulation of genes exerting a powerful negative control, and down-regulation of genes critical to cell migration and extracellular matrix-cytoskeleton coupling, all alterations that provide an impediment to correct angiogenesis. We also identified transcripts controlling haemostasis, inflammation, stimulus transduction, transcription, protein synthesis, and genome organization. An up-regulation of transcripts related to protein degradation and ubiquitination was observed in SSc endothelial cells. We have validated data on the main anti-angiogenesis-related genes by RT-PCR, western blotting, in vitro angiogenesis and immunohistochemistry. These observations indicate that microvascular endothelial cells of patients with SSc show abnormalities in a variety of genes that are able to account for defective angiogenesis

Cell culture-derived influenza vaccines from Vero cells: a new horizon for vaccine production

In the 20th century, three influenza pandemics killed approximately 100 million people. The traditional method of influenza vaccine manufacturing is based on using chicken eggs. However, the necessity of the availability of millions of fertile eggs in the event of a pandemic has led research to focus on the development of cell culture-derived vaccines, which offer shorter lead-in times and greater flexibility of production. So far, the cell substrates being evaluated and in use include Vero, Madin–Darby canine kidney, PER.C6 and insect cells. However, Vero cells are the most widely accepted among others. This review introduces briefly the concepts of advanced cell culture-derived influenza vaccine production and highlights the advantages of these vaccines in terms of efficiency, speed and immunogenicity based on the clinical data obtained from different studies

Desmoglein-2-Integrin Beta-8 Interaction Regulates Actin Assembly in Endothelial Cells: Deregulation in Systemic Sclerosis

<div><p>Background</p><p>The inability of endothelial cells of patients affected by the diffuse form of Systemic sclerosis (SSc) to perform angiogenesis is a marker of the disease. We previously demonstrated that desmoglein-2 reduction is a major difference between (SSc)-microvascular endothelial cells (MVECs) and normal (N)-MVECs. Here we investigated the role of desmoglein-2 in human N-MVECs and SSc-MVECs angiogenesis.</p><p>Methodology/principal findings</p><p>Angiogenesis was studied by Matrigel invasion, capillary morphogenesis <i>in vitro</i> and Matrigel plug assay <i>in vivo</i>. Gene profiling was studied by Affymetrix technology and signal transduction by Western blotting. Colocalization was validated by immunoprecipitation and confocal microscopy. SiRNAs were used to validate the roles of specific molecules. We observed that desmoglein-2 co-localizes with integrin-beta8 in N-MVECs. This complex is required to signal through Rac, FAK, SMAD1/5 and MAP-kinases, promoting an angiogenic program. Inhibition of desmoglein-2 by <i>DSG2-</i>siRNA impaired actin stress fibres formation, capillary morphogenesis <i>in vitro</i> and angiogenesis <i>in vivo</i>. Transcriptome profiling after <i>DSG2</i> inhibition revealed alterations of several genes involved in actin organization. siRNA inhibition of integrin-beta8 and RAC2 also resulted into capillary morphogenesis impairment in N-MVECs, due to reduced expression of the same actin-assembly genes that were down-regulated by <i>DSG2</i> silencing. SSc-MVECs showed down-regulation of the same genes in <i>DSG2</i>-siRNA treated N-MVECs, suggesting that impairment of desmoglein-2/integrin-beta8 complex contributes to angiogenesis derangement in SSc. Transfection of <i>DSG2</i> in SSc-MVEC partially restored their angiogenic properties <i>in vitro</i>.</p><p>Conclusions/significance</p><p>We have shown that impairment of actin assembly as a result of desmoglein-2/integrin-beta8 complex formation is a major factor contributing to angiogenesis deregulation in Systemic sclerosis.</p></div

Effects of <i>DSG2</i> silencing on <i>in vitro</i> parameters of angiogenesis of N-MVECs and <i>in vivo</i> Matrigel sponge assay.

<p>A) <i>DSG2</i> RT-PCR after <i>DSG2</i> silencing. Data are expressed as fold change (siCONTROL-N-MVEC = 1). B) Representative desmoglein-2 Western blotting after <i>DSG2</i> silencing. Results shown are representative of similar data obtained in 3 different experiments; molecular weights markers are to the right; beta-actin: loading control. The blot on the right refers to desmoglein-2 expression in three different SSc-MVEC lines (5, 6, and 7) used in the present study. C) Cell viability evaluated by WST-1 assay, D) proliferation and E) matrigel invasion in <i>DSG2</i> silenced and control N-MVECs. Results are the mean ± SD of three different experiments performed in triplicate. *p<0.05, significantly different from control. F) Capillary morphogenesis at 6 h after seeding in Matrigel of control and treated N-MVECs. Numbers: percent field occupancy, taking control as 100%. Insets: morphology 24 hours after seeding. Data are from 3 experiments performed in triplicate. G) si<i>DSG2</i>-inhibition of angiogenesis in the Matrigel sponge model in mice. Upper part: angiogenesis quantification by haemoglobin content of each sponge. Pictures: ZEISS SR stereomicroscope aspect of the sponges under conditions corresponding to the histograms. Graphs are mean ± SD; * p<0.05. Results are the mean of three experiments (one animal for each condition, four Matrigel sponges in each animal).</p