A Temperature-Sensitive Recombinant of Avian Coronavirus Infectious Bronchitis Virus Provides Complete Protection against Homologous Challenge.

Avian coronavirus infectious bronchitis virus (IBV) is the etiological agent of infectious bronchitis, an acute highly contagious economically relevant respiratory disease of poultry. Vaccination is used to control IBV infections, with live-attenuated vaccines generated via serial passage of a virulent field isolate through embryonated hens' eggs. A fine balance must be achieved between attenuation and the retention of immunogenicity. The exact molecular mechanism of attenuation is unknown, and vaccines produced in this manner present a risk of reversion to virulence as few consensus level changes are acquired. Our previous research resulted in the generation of a recombinant IBV (rIBV) known as M41-R, based on a pathogenic strain M41-CK. M41-R was attenuated in vivo by two amino acid changes, Nsp10-Pro85Leu and Nsp14-Val393Leu; however, the mechanism of attenuation was not determined. Pro85 and Val393 were found to be conserved among not only IBV strains but members of the wider coronavirus family. This study demonstrates that the same changes are associated with a temperature-sensitive (ts) replication phenotype at 41°C in vitro, suggesting that the two phenotypes may be linked. Vaccination of specific-pathogen-free chickens with M41-R induced 100% protection against clinical disease, tracheal ciliary damage, and challenge virus replication following homologous challenge with virulent M41-CK. Temperature sensitivity has been used to rationally attenuate other viral pathogens, including influenza, and the identification of amino acid changes that impart both a ts and an attenuated phenotype may therefore offer an avenue for future coronavirus vaccine development. IMPORTANCE Infectious bronchitis virus is a pathogen of economic and welfare concern for the global poultry industry. Live-attenuated vaccines against are generated by serial passage of a virulent isolate in embryonated eggs until attenuation is achieved. The exact mechanisms of attenuation are unknown, and vaccines produced have a risk of reversion to virulence. Reverse genetics provides a method to generate vaccines that are rationally attenuated and are more stable with respect to back selection due to their clonal origin. Genetic populations resulting from molecular clones are more homogeneous and lack the presence of parental pathogenic viruses, which generation by multiple passage does not. In this study, we identified two amino acids that impart a temperature-sensitive replication phenotype. Immunogenicity is retained and vaccination results in 100% protection against homologous challenge. Temperature sensitivity, used for the development of vaccines against other viruses, presents a method for the development of coronavirus vaccines.

A Highly Potent SARS-CoV-2 Blocking Lectin Protein.

The COVID-19 (coronavirus disease-19) pandemic affected more than 180 million people around the globe, causing more than five million deaths as of January 2022. SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), the new coronavirus, has been identified as the primary cause of the infection. The number of vaccinated people is increasing; however, prophylactic drugs are highly demanded to ensure secure social contact. A number of drug molecules have been repurposed to fight against SARS-CoV-2, and some of them have been proven to be effective in preventing hospitalization or ICU admissions. Here, we demonstrated griffithsin (GRFT), a lectin protein, to block the entry of SARS-CoV-2 and its variants, Delta and Omicron, into the Vero E6 cell lines and IFNAR-/- mouse models by attaching to the spike protein of SARS-CoV-2. Given the current mutation frequency of SARS-CoV-2, we believe that GRFT protein-based drugs will have a high impact in preventing the transmission of both the Wuhan strain as well as any other emerging variants, including Delta and Omicron variants, causing the high-speed spread of COVID-19.

Guidance on the special care of liver or kidney transplant recipients diagnosed with COVID-19 / Az új koronavírus (SARS-CoV-2) okozta fertozésben szenvedo vese- és májátültetett betegek ellátásának speciális szempontjai. (A COVID-19-pandémia orvosszakmai kérdései)

Due to the COVID-19 pandemic caused by infection with the novel, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), transplant medicine also had to face a new, hitherto unknown challenge. To be prepared for any possibility, we consider it important to summarize the current knowledge regarding COVID-19 of liver and kidney transplant patients. Very early reports from Spanish and French registry recorded fatality rates of 18.6% and 13%, respectively, in renal patients which suggests a moderately worse outcome compared to the general population. In patients with positive PCR test but not showing clinical signs, the reduction of immunosuppression is not advised. In the case of gastrointestinal or respiratory signs with fever, the discontinuation of mycophenolate or mTOR inhibitors is recommended with decrease of the trough levels of calcineurin inhibitors to the lowest effective limit. Stop (kidney transplanted patients) or decrease (liver transplanted patients) immunosuppression and maintain corticosteroids when pulmonal injury develops and consider anti-IL1 and anti-IL6 monoclonal antibody use when hyperinflammatory syndrome is evolving. No proven effective treatment for SARS-CoV-2 exists currently. The use of lopinavir/ritonavir should be avoided because of the severe drug interaction with calcineurin inhibitors. The efficacy and tolerability of hidroxychloroquin remains to be also questionable; enroll patients into clinical trial with remdesivir or favipiravir if available. COVID-19 is characterized by virus-induced endothelial dysfunction, procoagulant state and renin-angiotensin-aldosteron system imbalance. Early thromboprofilaxis combination with low-molecular-weight heparin and low-dose aspirin is strongly recommended with the maintenance of angiotensin-converting enzyme inhibitor (ACEI) or angiotensin-II-receptor blocker (ARB) therapy when they were prescribed earlier. Orv Hetil. 2020; 161(32): 1310-1321.