Development Of An Gene-engineered Rbc Vaccine And Evaluation To The Effect Of Dihydroquercetin For The Prevention Of COVID-19

The coronavirus disease 2019(COVID-19)caused by the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),a highly contagious coronavirus,has spread around the world and now poses a serious threat to social health systems,the global economy,and even global governance.The situation of the COVID-19 indicates that the prevention of COVID-19 has become a common concern worldwide.Therefore,this study aims to develop new preventive strategies for COVID-19.Two works based on vaccine prevention and drug prevention were carried out to provide new options for COVID-19 prevention.We constructed a gene-engineered red blood cell(RBC)SARS-CoV-2 vaccine and explored the preventive effect of Dihydroquercetin on SARS-CoV-2 infection in a Syrian hamster model.The RBD region of the S protein on the surface of SARS-CoV-2 contains abundant antigenic epitopes and is a key target of interest for vaccine development.CpG oligonucleotide(CpG ODN)is an immunostimulatory containing non-methylated DNA oligonucleotide sequence with adjuvant effect.In order to effectively induce humoral and cellular immune responses,a gene-engineered RBC SARS-CoV-2 vaccine was constructed in this study using RBCs as the vaccine vector,expressing RBD as the immunogen using genetic engineering technology,and the RBCs were further combined with CpG ODN adjuvant.Firstly,the lentiviral vector expressing RBD(RBD-LVs)was prepared.The RBD lentiviral vector construction and RBD expression were verified by flow cytometry and fluorescence microscopy techniques.Further,red progenitor cells were transfected with the RBC-LVs.Finally,denucleated mature RBCs were combined with CpG ODN adjuvant to obtain gene-engineered RBC SARS-CoV-2 vaccine.The results of flow cytometry showed that RBD-LVs successfully transfected red lineage progenitor cells.The transfection efficiency of RBD-LVs was 10% and the binding rate of RBC to CpG ODN was 100%.These results indicated the successful construction of the gene-engineered RBC SARS-CoV-2 vaccine.Dihydroquercetin is a natural compound extracted from the roots of larch in the alpine zone,that can effectively scavenge free radicals and toxins in the body.It has various biological activities such as anti-cancer,anti-inflammatory,anti-allergic,and anti-viral.Researches have shown that Dihydroquercetin has anti-SARS-CoV-2 potential,but it has not been validated in vivo or in vitro.In this study,we initially explored the preventive effect of Dihydroquercetin against SARS-CoV-2 by using the SARS-CoV-2 infection Syrian hamster model.The experimental results showed that the nasal,pharyngeal,lung tissue,and bronchoalveolar lavage fluid viral loads were reduced in the Dihydroquercetin group compared to the infected group of SARS-CoV-2-infected Syrian hamsters.The results of inflammatory factor levels and H&E staining pathology analysis confirmed that Dihydroquercetin reduced the inflammatory response triggered by the SARS-CoV-2 infection.These results suggest that Dihydroquercetin has a good preventive effect in SARS-CoV-2-infected Syrian hamsters.This study provides two strategies for the prevention of COVID-19.Firstly,a gene-engineered RBC SARS-CoV-2 vaccine platform was constructed to provide a new platform for dealing with mutations of SARS-CoV-2.Secondly,the preventive effect of Dihydroquercetin on SARS-CoV-2 was initially verified.These two strategies add new options for the development of preventive drugs for COVID-19,are scientifically important,and have wide application for the prevention of COVID-19.