Study On In Vitro Activity Of Covid-19 Neutralizing Antibody

Since the outbreak in novel coronavirus in late December,2019,coronavirus19(COVID-19)has gradually spread around the world,becoming a major public health event.Great efforts have been made all over the world to study the effective treatment of COVID-19,but there is no special antiviral drug for COVID-19 caused by SARS-CoV-2.Neutralizing antibody is the most effective tool against virus.Antibodies are protective protein produced by the immune system after the body is stimulated by antigens such as viruses.They can identify specific foreign objects,help clear the invading pathogenic organisms or prevent them from entering cells.The ways to obtain antiviral antibodies can be roughly divided into two categories: one is to separate from the blood of immune people or animals;The other method is to screen and design antibodies,and prepare a large number of antibody drugs in vitro.These drugs have high antiviral specificity,for example,they have played a great role in fighting Ebola virus and Middle East Respiratory Syndrome coronavirus(MERS-CoV).Activity measurement is the measurement of the effective components and contents of drugs and drug potency,and it is an important quality control index to ensure the effectiveness of antibody drugs.The biological activity of antibody drugs in novel coronavirus was studied in this paper.The main research contents include:1.Study on the method of novel coronavirus antibody binding activityBased on the biological activity of novel coronavirus antibody,this topic successfully established and optimized the indirect method to measure the binding activity of COVID-19 antibody,which was proved to be sensitive,specific,rapid and stable.It provides a reference for the quality research and activity determination of COVID-19 antibody,and also provides a train of thought for the establishment of biological activity determination methods of other antibodies.2.Study on competitive binding activity of novel coronavirus antibody.Based on the biological activity of neutralizing antibodies against novel coronavirus,a method for measuring the competitive binding activity of neutralizing antibodies against novel coronavirus was successfully established and optimized,and the method also showed good durability when the antigen RBD-m Fc coating concentration,antibody incubation time and TMB color development time were slightly changed intentionally.The verification of the method shows that the method has good accuracy,precision,specificity and linearity.By supplementing the competitive ability of COVID-19 antibody and ACE2 antibody,this method provides another idea for detecting the biological activity of COVID-19 antibody,and also provides a basis for the quality research and activity determination of COVID-19 antibody.3.Study on neutralizing activity of pseudovirusSevere acute respiratory syndrome coronavirus type 2(SARS-CoV-2)is a highly pathogenic and infectious virus.Because the experiments related to live viruses must be handled under the Biosafety Level 3 conditions,it hinders the development of vaccines and therapeutic drugs.Pseudovirus has become a useful virology tool instead of live virus because of its safety and versatility,especially for newly discovered and repeated viruses.Therefore,with the help of VSV pseudovirus production system,scientists have developed a pseudovirus based neutralization test to evaluate the anti SARS-CoV-2 neutralizing antibody in Level 2 biosafety facilities.This paper established and verified a method to study the neutralization activity of SARS-CoV-2 pseudovirus based on the expression of ACE2,a cellular mechanism receptor.First,by comparing the protein expression and relative m RNA content of angiotensin converting enzyme 2(ACE2),HEK293T-h ACE2 cells with the highest expression of ACE2 were selected as experimental cells.Then,by exploring the number and proportion of virus and cells,incubation time,etc,To establish and validate the research method of neutralizing activity of SARS-CoV-2 pseudovirus.