Science Latest Results: Isolated SARS-CoV-2 neutralizing antibodies to effectively protect animals against virus attacks!

Novel coronavirus pneumonia (COVID-19) continues to damage the global health. There is no cure and no licensed vaccine.obtaining pathogen neutralizing antibodies (nabs) of new coronavirus (sars-cov-2) may be a potential prevention and treatment option, which can also help guide vaccine design.on June 15, the research team from Scripps Research Institute published the latest research results of neutralizing antibodies against sars-cov-2 in science. They separated effective neutralizing antibodies (nabs) against two epitopes on receptor binding domain (RBD) and different non RBD epitopes on spike protein (s). It was found that the use of nabs could be attacked by high-dose sars-cov-2 The Syrian hamster provides protection.DOI: 10.1126/ science.abc7520 Specifically, the researchers recruited 17 patients with sars-cov-2 infection in California to collect peripheral blood mononuclear cells (PBMC) and plasma.at the same time, a hela-ace2 cell line with strong and repeatable viral titer was developed. The binding of donor plasma to recombinant sars-cov-2 s protein and receptor binding domain (RBD) protein was tested by pseudovirus (PSV) neutralization assay.the results showed that the binding potency of donor plasma to sars-cov-2s protein changed greatly, but the potency to RBD decreased by an order of magnitude.neutralizing antibody separation strategy for sars-cov-2. Subsequently, eight donors were identified with monoclonal antibodies (mAbs), and 2045 antibodies were cloned and expressed. Their binding to RBD and S proteins and neutralization of sars-cov-2 PSV were tested.the results were unexpected. The virus infection was more responsive to the non RBD region of S protein, but only a small part was neutralized.on the contrary, RBD binding antibody was less, but it could neutralize a high proportion of sars-cov-2 pseudovirus.separation and functional screening of antibodies for SARS CoV antigen binding and neutralization. Then, the researchers used s protein and RBD protein as capture antigen to detect antibodies bound to non competitive sites, and found three antigenic determinant boxes (rbd-a, rbd-b and rbd-c) of RBD and three antigenic determinant boxes (SA, Sb and SC) of S-protein.therefore, they continued to evaluate the neutralization activity of monoclonal antibodies against sars-cov-2 and sars-cov-1 Pseudoviruses.the results showed that the most effective neutralizing antibody was the antibody against rbd-a epitope, including two antibodies cc6.29 and cc6.30, which could effectively neutralize sars-cov-2 pseudovirus, while cc6.33 against rbd-b could neutralize sars-cov-2 and sars-cov-1 at the same time.through cell surface competition test and surface plasmon resonance (SPR) experiment, the researchers determined that the epitope rbd-a was the preferred target to trigger neutralizing antibody, and the corresponding increase of affinity between mAb and rbd-a may lead to the corresponding increase of neutralization force.it is worth noting that the above three antibodies can neutralize the mutated sars-cov-2 virus.sars-cov-2 neutralizing monoclonal antibody protects Syrian hamsters from weight loss and pulmonary virus replication. In order to study the in vivo protection of sars-cov-2 by neutralizing antibodies in vitro, two mAbs were selected to treat Syrian hamster models.the unrelated antibody den3 against dengue virus was used as the control, and hamsters were weighed as a measure of disease caused by infection.the results showed that the average weight loss of the control group was 13.6% in the cc12.1 targeted rbd-a epitope treatment, while no weight loss was found in the experimental group receiving neutralizing rbd-a antibody at the dose of 2 mg or 500 μ g. the lung virus load was further verified by real-time PCR. the researchers measured the antibody serum concentration before the Syrian hamster intranasal virus attack, and found that the antibody serum concentration of about 22 μ g / ml provided comprehensive protection, and the serum concentration of 12 μ g / ml was enough to reduce the disease caused by weight loss by 50%. however, the effective antibody concentration needed to prevent disease in the infected site remains to be determined. in conclusion, this study shows that nab plays a role in the prevention and potential treatment of covid-19. at the same time, the protective epitopes of NAB are also defined, which can be used to guide vaccine design. it is worth noting that in addition to this study, science also published four other research results on antibodies against new coronavirus, including human neutralizing antibodies and antibody "cocktail therapy" on the same day. the results of neutralizing antibodies against new coronavirus have been published frequently. novel coronavirus pneumonia is a new form of clinical application. We hope that these research results can promote clinical application as soon as possible, and provide powerful medical intervention for the treatment and prevention of new crown pneumonia. end References: [1] isolation of potential sars-cov-2 neutralizing antibiotics and protection from disease in a small animal model