Project description:Since December 2019, the novel human Coronavirus SARS-CoV-2 has spread globally, causing millions of deaths. Unprecedented efforts have enabled development and authorization of a range of vaccines, which reduce transmission rates and confer protection against the associated disease COVID-19. These vaccines are conceptually diverse, including e.g. classical adjuvanted whole-inactivated virus, viral vectors, and mRNA vaccines. We have analysed two prototypic model vaccines, the strongly TH1-biased measles vaccine-derived candidate MeVvac2-SARS2-S(H) and a TH2-biased Alum-adjuvanted, non-stabilized Spike protein side-by-side, for their ability to protect Syrian hamsters upon challenge with a low-passage SARS-CoV-2 patient isolate. The MeVvac2-SARS2-S(H) vaccine protected the hamsters from severe disease. In contrast, the protein vaccine induced vaccine-associated enhanced respiratory disease (VAERD) with massive infiltration of eosinophils into the lungs. Global RNA-Seq analysis of hamster lungs revealed reduced viral RNA and less host dysregulation in MeVvac2-SARS2-S(H) vaccinated animals, while S protein vaccination triggered enhanced host gene dysregulation when compared to unvaccinated control animals. Of note, mRNAs encoding the major eosinophil attractant CCL-11, the TH2 response-driving cytokine IL-19, as well as TH2-cytokines IL-4, IL-5, and IL-13 were exclusively up-regulated in the lungs of S protein vaccinated animals, consistent with previously described VAERD induced by RSV vaccine candidates. IL-4, IL-5, and IL-13 were also up-regulated in S-specific splenocytes after protein vaccination. Using scRNA-Seq, T cells and innate lymphoid cells were identified as the source of these cytokines, while CCL11 and IL-19 mRNAs was found in interstitial macrophages displaying an activated phenotype. Interestingly, the amount of viral reads in this macrophage population correlated with the abundance of Fc-receptor reads. These findings suggest that VAERD is triggered by induction of TH2-type helper cells secreting IL-4, IL-5, and IL-13, together with stimulation of macrophages dependent on Fc-receptor mediated uptake of virus complexed with non-neutralizing antibodies. Via this mechanism, uncontrolled eosinophil recruitment to the infected tissue occurs, a hallmark of VAERD immunopathogenesis. These effects could effectively be treated using dexamethasone and were not observed in animals vaccinated with MeVvac2-SARS2-S(H). Taken together, our data validate the potential for, and identify the transcriptional mediators that underlie VAERD and their cellular origins, in the context of protein-based TH2-biased COVID-19 vaccines. Dexamethasone, which is already in use for treatment of severe COVID-19, may alleviate such VAERD, but in-depth scrutiny of any next-generation protein-based vaccine candidates is required, prior and after their regulatory approval.

Project description:Acute lung inflammation can alter the pulmonary function of susceptible individuals and exacerbate the pathogenesis of chronic inflammatory lung diseases including chronic obstructive pulmonary disease (COPD), cystic fibrosis and asthma. Exposure to lipopolysaccharide (LPS) or endotoxin, a constituent of outer cell membrane of gram negative bacteria, induces airway inflammation that is primarily characterized by increased polymorphonuclear neutrophils (PMNs) at early time points. Because LPS is present in variety of occupational and home environments and is an active constituent of cigarette smoke it is a risk factor for increasing prevalence and severity of non-occupational COPD, for adult onset of asthma and for wheezing in children. In airway epithelial cells, LPS stimulation increases mucin gene expression and mucous production. Hypersecretion of mucus overwhelms the ciliary clearance and obstructs airways, causing morbidity and mortality in chronic inflammatory respiratory lung diseases. In addition, acute bacterial infection contributes to the exacerbation of chronic airway diseases, specifically in advanced COPD and CF subjects, leading to increased healthcare burden and higher mortality. Bcl-2, a prosurvival protein that inhibits cell death plays a key role in normal cellular homeostasis and regulates the integrity of the mitochondrial and endoplasmic reticulum membranes. Gain- and loss-of-function studies showed that Bcl-2 expression sustains hyperplastic epithelial cells, and Bcl-2 expression is elevated in airway epithelial cells of subjects with cystic fibrosis and asthma. The present study investigated which inflammatory mediators induce mucous cell metaplasia and Bcl-2 expression following LPS exposure. Microarray analyses of mRNA from airway epithelial cells captured by laser microdissection from rat lungs snap-frozen at day 0 and 2 post LPS exposure were analyzed. Microarray analysis of mRNA from airway epithelial cells captured by laser microdissection from rat lungs snap-frozen at day 0 and day 2 post LPS exposure was performed to identify inflammatory mediators modulated by LPS exposure. Specific pathogen-free F344/NCrR male rats of 8–10 wk of age (from NCI, Frederick, MD) were exposed to LPS (1000 ug in 0.5 ML Saline) and rats were sacrificed on day 0 and day 2 of LPS exposure. Right lungs were snap-frozen in OCT and airway epithelial cells were captured by laser-dissection microsopy to extract RNA. Gene expression data from nonexposed rats (0d) was used a control.

Project description:Acute lung inflammation can alter the pulmonary function of susceptible individuals and exacerbate the pathogenesis of chronic inflammatory lung diseases including chronic obstructive pulmonary disease (COPD), cystic fibrosis and asthma. Exposure to lipopolysaccharide (LPS) or endotoxin, a constituent of outer cell membrane of gram negative bacteria, induces airway inflammation that is primarily characterized by increased polymorphonuclear neutrophils (PMNs) at early time points. Because LPS is present in variety of occupational and home environments and is an active constituent of cigarette smoke it is a risk factor for increasing prevalence and severity of non-occupational COPD, for adult onset of asthma and for wheezing in children. In airway epithelial cells, LPS stimulation increases mucin gene expression and mucous production. Hypersecretion of mucus overwhelms the ciliary clearance and obstructs airways, causing morbidity and mortality in chronic inflammatory respiratory lung diseases. In addition, acute bacterial infection contributes to the exacerbation of chronic airway diseases, specifically in advanced COPD and CF subjects, leading to increased healthcare burden and higher mortality. Bcl-2, a prosurvival protein that inhibits cell death plays a key role in normal cellular homeostasis and regulates the integrity of the mitochondrial and endoplasmic reticulum membranes. Gain- and loss-of-function studies showed that Bcl-2 expression sustains hyperplastic epithelial cells, and Bcl-2 expression is elevated in airway epithelial cells of subjects with cystic fibrosis and asthma. The present study investigated which inflammatory mediators induce mucous cell metaplasia and Bcl-2 expression following LPS exposure. Microarray analyses of mRNA from airway epithelial cells captured by laser microdissection from rat lungs snap-frozen at day 0 and 2 post LPS exposure were analyzed. Microarray analysis of mRNA from airway epithelial cells captured by laser microdissection from rat lungs snap-frozen at day 0 and day 2 post LPS exposure was performed to identify inflammatory mediators modulated by LPS exposure.

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Recombinant RSV G protein vaccine induces enhanced respiratory disease via IL-13 and mucin overproduction

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