Blocking COVID with Antibodies

As the number of global coronavirus cases continues to increase beyond 20 million, there is an urgent need for treatment for those infected with SARS CoV2. Internationally, biotech companies are working feverishly towards developing a vaccine to reduce infection rates. However, it is still unclear when a final product will be released and to what degree of immunity will be achieved. Until a permanent solution can be developed, it appears that monoclonal antibodies (mAbs) which are frequently used in cancer treatment may provide temporary immunity to SARSCoV-2. (1)

These mAbs are a form of immunotherapy which can bind to and neutralize antagonistic antigens. For COVID-19, treatment involves intravenous infusion of the recommended concentration of neutralizing antibodies that adhere to the S domain on the spike protein. Attachment of the antibody to a viral particle inhibits binding of the spike protein to the ACE2 receptor on the cell membrane.

By blocking the binding of the bspikes to the cell, the antibody prevents the virus from entering and replicating within the cell. (2)

Current data published by Regeneron Pharmaceuticals indicates that antibody therapy may prove vital to immunocompromised individuals suffering from COVID-19. In their study, they looked at the effects of their neutralizing antibody cocktail (REGN-COV2) on SARS-CoV2 infected rhesus macaques and golden hamsters.

To assess the efficacy of the treatment, nasopharyngeal and oral swabs were collected every other day for seven days and measured for viral load (gRNA, sgRNA). The data suggests that infusion of 50 mg/kg of neutralizing antibody greatly reduced the viral RNA load by the second day of therapy compared to the placebo group. Further pathological analyses of lung tissue in the control groups showed obvious signs of interstitial pneumonia in the placebo group, with minor to no signs of pneumonia in groups that received 0.3 mg/kg, or 50 mg/kg of REGN-COV2. (3)

In conclusion, the use of neutralizing antibody-based immunotherapy has shown promising results in preliminary animal testing. The data suggests that viral replication can be blocked very quickly, which may support a prompt recovery from SARS-CoV-2 infection. (3)

Although neutralizing antibody treatment is not permanent, researchers believe immunity could last up to six months. If this type of therapy is approved for treatment of patients, this could potentially provide sufficient time for a more permanent solution to be developed. (1)

References:

  1. https://www.medscape.com/viewarticle/935018?nlid=136721_5402&src=wnl_dne_200805_mscpedit&uac=166752BK&impID=2491809&faf=1
  2. https://apjai-journal.org/wp-content/uploads/2020/03/2.pdf
  3. https://www.biorxiv.org/content/10.1101/2020.08.02.233320v1.full

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