by Professor Gino Martini, RPS Chief Scientist
As the race to develop a vaccine against COVID-19 advances, a number of researchers are focusing on finding a short-term way to treat people with the disease by using monoclonal antibodies or mAbs. Rather than developing vaccines to coax the body’s immune system to make its own antibodies, the concept is to inject designer versions of these antibodies to kill the SARS-CoV-2 virus directly. The use of mAbs is popular in the field of cancer treatment and now possibly in combating COVID-19. So how does this work?
Our wonderful Immune System
Our immune system is designed to attack antigens, such as cancer cells and viruses by making proteins called antibodies. These antibodies will circulate throughout the body and will identify these foreign antigens. Attachment of the antibody to the antigen can neutralise the antigen directly and signal to the immune system to release more antibodies.
Researchers can design antibodies that specifically target a certain antigen, such as those found on cancer cells. Once isolated, they can then make many copies of that antibody in the lab, hence the term monoclonal antibodies.
What mAbs are made of
Monoclonal antibodies are man-made proteins that act like human antibodies in the immune system. There are 4 different ways they can be made and are named based on what they are made of.
- Murine: These are made from mouse proteins and the names of the treatments end in -omab.
- Chimeric: These proteins are a combination of part mouse and part human and the names of the treatments end in -ximab.
- Humanized: These are made from small parts of mouse proteins attached to human proteins and the names of the treatments end in -zumab
- Human: These are fully human proteins and the names of the treatments end in -umab.
How are mAbs being used to treat COVID 19?
In this approach, researchers isolate antibodies from recovering patients and identify those that best ‘neutralize’ the virus, binding it to and keeping it from replicating. Researchers then produce these antibodies in bulk in the laboratory. If the treatment is found to be effective, companies will scale up production, using cells grown in giant bioreactors.
mAbs differs from ‘convalescent plasma’ treatments, an approach composed of a complex mixture of antibodies and molecules taken directly from the blood of people recovering from COVID-19 and used to treat other patients.
It is important to note that the effects of both approaches are short term; neither type of treatment will produce a long-lasting immune response.
NHS Blood+Transplant are calling for volunteers of those who have recovered from COVID-19 for their clinical trials; your antibody-rich plasma could help other patients to recover from the virus.
As I write this blog – AstraZeneca has just announced that they have just initiated a Phase 1 clinical trial and dosed participants with a combination of two monoclonal antibodies (mAbs) in development for the prevention and treatment of COVID-19.
Let’s hope the trial is successful – I am confident that Pharma and UK life sciences will deliver!