11th Aug 2020
11th Aug 2020
Curated by Endre Szvetnik
The world and researchers have been focusing on the race to create the first vaccine that can effectively stop the spread of COVID-19. However there are other ways to block the replication of the virus, that can be a stopgap measure and save many lives before vaccines become available.
So-called monoclonal antibodies or mAbs (already in use as drugs to treat cancer and autoimmune diseases) have been receiving much less attention in terms of COVID-19. However, they may offer both the potential of preventing an infection becoming severe and a fast and effective, but short-term treatment. Our immune system typically responds to viral infection by generating a diverse range of antibodies that can selectively bind components of the virus. Monoclonal antibodies are engineered versions that can be mass produced through biotechnology. Recent studies have shown that antibodies isolated from the blood plasma of COVID-19 survivors and then engineered into mAbs can block the “handshake” between the spike protein on SARS-CoV-2 and the human ACE-2 receptor – the mechanism by which the virus gets into our cells and starts multiplying. Researchers who detailed their findings in this paper have isolated three types of antibodies from the blood of recovered COVID-19 patients. Their tests showed that 2 out of the 3 antibodies could effectively block the virus from docking onto human cells and thus stop the infection from developing. Several mAbs have entered clinical trials in the summer of 2020 and we are now waiting for data about their safety and effectiveness
What is the difference between monoclonal antibodies and vaccines? Vaccines prompt the immune system to start generating its own antibodies that can help defeat the virus. Monoclonal antibodies, on the other hand, are ‘ready-made’ in a bioreactor. Vaccines and mAbs both have their benefits and drawbacks. Whereas vaccines can take weeks to ‘kick in’ the immune response in the body, mAbs can go to battle with the virus almost instantly when they have been injected into our bloodstream. However, as they are not replenished by our immune system, mAbs are eliminated from the bloodstream within a month or so. Vaccines, in general, offer more long-term protection. The faster acting capacity of mAbs means that they could be used to prevent infection or protect highly vulnerable people, such as healthcare workers and others in contagious environments or older people in care homes. They could also be administered to at-risk people who develop COVID-19 symptoms to stop them from falling severely ill. We are still learning about the immune reaction to COVID-19 and antibodies may play a lesser role in neutralising the virus compared to our specialised immune cells, which may limit our ability to discover effective mAbs. However, there are also other routes of discovery, for example engineering or using antibodies generated by animals. While mAbs could be a promising therapeutic option, if new mutations of SARS-CoV-2 emerge, monoclonal antibodies specific to older strains could become ineffective. Still, preliminary results suggest that they are safe to use and help manage the pandemic before vaccines become available.
Here is the current state of science on a Sparrho pinboard.
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