Studying antibodies have been one of the keys to understanding coronavirus and vital for vaccine development. Researchers have recently come across certain antibodies that may protect the respiratory system against COVID-19.
Researchers from the University of Massachusetts Medical School's MassBiologics, a vaccine developer and manufacturer, recently published a study in the journal Nature Communications. Their paper analyzes how effective monoclonal antibodies called sIgA can be effective in protecting the respiratory system against the virus and its possible usage as an ingredient for future vaccines.
Dr. Yang Wang and his team described that the cross-reactive human monoclonal antibody (MAB) can block the ACE2 receptor from binding to the coronavirus spike protein, which can then prevent or limit the spread of infection. This all occurs in the respiratory tract, where the COVID-19 infection initially starts.
ACE2 receptors are proteins on the surface of several cell types, which acts as an enzyme to generate small proteins and regulates cell function. SARS-CoV-2 spike proteins attach to the ACE2 receptor to rapidly spread viral infection.
SARS Antibody
The team at MassBiologics had been one of the earliest teams to respond to the pandemic by researching how to prevent and treat coronavirus. Their current research goes back to developing an IgG monoclonal antibody that was effective against Severe Acute Respiratory Syndrome, the first SARS virus, nearly 16 years ago.
The old SARS program was revived by thawing frozen hybridoma cells that the company developed years ago, hoping that it would work with the second SARS virus which has a 90% similarity to the first kind. However, the IgG monoclonal antibody would not bind to SARS-Cov-2.
They then referred to a separate research program involving secretory IgAs (sIgA) antibodies that are an important part of the immune system. Previously, sIgA was being assessed as a possible treatment for gastrointestinal infections. A similar approach worked in the respiratory tract as an antibody called MAb362 neutralized the spread of coronavirus infection.
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IgA Antibody
'We were excited to learn that antibodies to SARS-CoV-2 are more effective in binding to and neutralizing the virus when they are in the sIgA isotype of antibody, compared to the usual circulating IgG antibodies,' said Dr. Mark Klempner. sIgA antibodies naturally coat mucosal surfaces like the respiratory, gastrointestinal, and genitourinary tracts, 'where they are stabilized by the mucous layer on these surfaces,' explained Dr. Klempner. The antibodies then function by 'preventing binding of a pathogen to host cells, thus preventing infection.'
MassBiologics also worked alongside Dr. Celia Schiffer of the Gladys Smith Martin Chair in Oncology and director of the Institute for Drug Resistance as well as Shurong Hou. They discovered that the MAb362 was similar to another antibody called MAb 80R, which neutralizes the SARS-CoV-2 by blocking the S proteins from binding to hACE2 receptors.
'So our search -which started during a coffee break conversation has resulted in a unique IgA antibody that could potentially be applied through mucosal administration, in combination with other systemically administrated therapeutics for direct mucosal protection,' shared Dr. Klempner.
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