ABSTRACT
SARS-CoV-2 continues to accumulate mutations to evade immunity, leading to breakthrough infections after vaccination. How researchers can anticipate the evolutionary trajectory of the virus in advance in the design of next-generation vaccines requires investigation. Here, we performed a comprehensive study of 11,650,487 SARS-CoV-2 sequences, which revealed that the SARS-CoV-2 spike (S) protein evolved not randomly but into directional paths of either high infectivity plus low immune resistance or low infectivity plus high immune resistance. The viral infectivity and immune resistance of variants are generally incompatible, except for limited variants such as Beta and Kappa. The Omicron variant has the highest immune resistance but showed high infectivity in only one of the tested cell lines. To provide cross-clade immunity against variants that undergo diverse evolutionary pathways, we designed a new pan-vaccine antigen (Span). Span was designed by analyzing the homology of 2675 SARS-CoV-2 S protein sequences from the NCBI database before the Delta variant emerged. The refined Span protein harbors high-frequency residues at given positions that reflect cross-clade generality in sequence evolution. Compared with a prototype wild-type (Swt) vaccine, which, when administered to mice, induced serum with decreased neutralization activity against emerging variants, Span vaccination of mice elicited broad immunity to a wide range of variants, including those that emerged after our design. Moreover, vaccinating mice with a heterologous Span booster conferred complete protection against lethal infection with the Omicron variant. Our results highlight the importance and feasibility of a universal vaccine to fight against SARS-CoV-2 antigenic drift.
ABSTRACT
OBJECTIVE To find out whether 2811 will cause toxic reactions in animals, and determine the safe dose of without any toxic reactions and the relationship between the dose, time of administration and results of the toxicity test. METHODS Thirty healthy rhesus monkeys were selected and randomly divided into 3 groups, 1 O in each group (half males and half females), namely, the solvent control group, 2811 100 and 400 mg* kg-1 groups, respectively. The solvent control group was iv given 0.9% sodium chloride injection, while the experimental groups were iv given 2811 100 and 400 mg* kg-1 , respectively, once every 6 days, 3 times in 2 weeks, and allowed to recover for 9 weeks after drug withdrawal. During the test, the body weight, food intakes, body temperatures, ophthalmology, blood pressure, electrocardiograms, blood routine, anticoagulation, blood biochemistry, electrolytes, urine, systemic anatomy, organ weight and coefficient were observed, while histopathology and immunology tests were performed. At the same time, the anti-drug antibody (ADA) and plasma concentrations were determined, and toxikinetic parameters were analyzed. RESULTS During the experiment, the observation of general symptoms, body mass, food intakes, body temperatures, ophthalmology, blood pressure, electrocardiograms, blood routine, anticoagulation, blood biochemistry, electrolytes, urine, organ weight and coefficient, histopathology and immunology of animals in each dose group showed no significant changes related to the tested animals. ADA was not detected in any of the groups. Plasma drug concentrations in 2B11 100 and 400 mg* kg-1 groups were basically consistent and proportional to the dose, so was the ratio of peak concentration and exposure. 2B11 injection showed linear kinetics in vivo. CONCLUSION Under the conditions set in this test, the 2-week repeated administration toxicity test of 2B11 in rhesus monkeys is safe, and no clinical adverse reactions are observed at the dose level of 400 mg*kg-1, which provides reference for the follow-up clinical study of 2B11. Copyright © 2022 Chinese Journal of Pharmacology and Toxicology. All rights reserved.
ABSTRACT
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has evolved into a pandemic, which has imposed a burden on the global economy and public health, thus effective response measures are urgently needed. Antibodies have a good historic documented in the prevention and treatment of emerging infectious diseases. At present, hundreds of development projects for SARS-CoV-2 neutralizing antibodies around the world are ongoing by using different strategies, with some in clinical trials. This article reviews the current development strategies and research progress of SARS-CoV-2 neutralizing antibodies in the fields of target selection, antibody screening techinqne, functional evaluation and possible challenges.
ABSTRACT
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has widely spread around the world, exerting great impacts on economic growth and human life. It is the highest priority to develop safe and effective drugs. Neutralizing antibodies have achieved good results in previous clinical applications of some viral infectious diseases. They can be used not only for the short-term prevention of SARS-COV-2 infection, but also for the treatment of corona virus disease 2019 (COVID-19), showing important application value. At present, the research and development of SARS-CoV-2 neutralizing antibody has made its rapid progress in China and abroad. Many antibody drugs have entered clinical trials and been put into emergency use. This article mainly summarizes targets of SARS-CoV-2 neutralizing antibody, screening technologies, drug development progresses and problems to be concerned.
ABSTRACT
Objective: To establish and verify a competitive ELISA method for the detection of blocking activity of monoclonal antibody against SARS-CoV-2 RBD, and to compare the results by correlation analysis with that of live virus neutralization activity measured by the plaque reduction neutralization test (PRNT). Methods: Using RBD-Fc as coating antigen, ACE2-His and anti-SARS-CoV-2 RBD monoclonal antibodies were added to competitively bind to RBD. Anti-6×his antibody labeled with horseradish peroxidase was used as the secondary antibody. The competitive ELISA method detecting the ability of McAb to block the binding of RBD to ACE2 was established. The specificity, relative accuracy, precision, linearity and range of the method were verified. Seven monoclonal antibodies against SARS-CoV-2 RBD were detected by this method. The results were compared with PRNT method, and correlation analysis was performed. Results: The blocking activity of the relevant anti-SARS-CoV-2 RBD monoclonal antibody on RBD and ACE2 protein can be effectively detected using the established competitive ELISA method. The blocking ability of McAb was dose-dependent and conformed to the four-parameter equation. The samples with theoretical titers of 64%, 80%, 100%, 125% and 156% were determined for 10 times, and the relative bias was within ±20%. The logarithm (abscissa) of theoretical potency value was used for linear regression to the logarithm (ordinate) of the corresponding titer determination value. The regression equation was y=1.156x-0.021 3, in which the slope was between 0.8 and 1.25, meaning good relative accuracy. The geometric coefficient of variation (GCV%) of the relative titers of each titer level were 2.6%, 5.2%, 3.6%, 3.4% and 10.2%, respectively, all of which were less than 20% with good precision. The correlation coefficient of linear regression equation was 0.985, meeting the requirements. The relative accuracy, intermediate precision and linearity of the method all met the requirements of the titer level range was 64%~156%. The detection results of the blocking activity of the 7 RBD monoclonal antibodies showed good correlation with the results of the live virus neutralization activity measured by the PRNT method. Conclusion: A competitive ELISA method for the detection of anti-SARS-CoV-2 RBD monoclonal antibody has been successfully established. The method has satisfied specificity, accuracy, precision and linearity. The results had a good correlation with that by PRNT method. It can be used to indirectly evaluate the neutralizing activity of related SARS-CoV-2 monoclonal antibodies against the live viruses.