There is an ongoing search for treatments to address worry and distress surrounding the global pandemic. In this article we will be learning about antibodies and new developments with animal testing. Before beginning human trials for COVID-19 therapies, researchers carried out several tests on animals. Monkeys and hamsters have been tested with a new antibody cocktail. With a mixture of two human antibodies, there is a hope that neutralizing antibodies have the power to treat and prevent SARS-CoV-2.
What are Antibodies?
Antibodies, also known as immunoglobulins, are proteins formed in B cells, they are essential for your immune system to combat viruses, bacteria and parasites. It all starts in the B cell, a type of white blood cell of the lymphocyte subtype. Their responsibility is to secrete antibodies, but first they have to become activated. When a B cell comes into contact with a foreign substance such as bacterium, we call that the antigen. The cell becomes activated with the help of a T cell. It then begins to clonal expand creating numerous copies of the antibodies they possess.
There are many specific antibodies, but they are mainly classified into five types (Deane, 2017):
IgE: Defense against helminth worms (and cause of the side effect of allergies)
IgA: General, found in mucus, saliva, breast milk, blood, and tears
IgG: Anti-bacterial and anti-virus, found in all tissues of the body. These are some of the few antibodies that can cross a mother’s placenta without causing damage to the offspring. There are multiple types of this kind.
IgM: Found in blood and lymph, first to be made in response to infection, involved in the B cell activation process
IgD: Involved in the B cell activation process
What are Monoclonal antibodies?
Now that we know what antibodies are, let's learn about how scientists and researchers use this information to combat viruses such as COVID-19.
Monoclonal antibodies are man made proteins created to bind to a specific substance. They are used in many drugs and are thought of as a precise tool to target diseases like cancer. Extracted B-cells are extracted and their ideal sequence is fused into a hybridoma to produce monoclonal antibody. B cells produce ‘polyclonal’ antibodies, the natural means of immunity. Monoclonal antibodies are unnatural and essentially produced by GMOs (the hybridoma). B cells quickly die after isolation… The cancer based cells used as factories are immortal (when treated correctly) and will pump out the same thing over and over, however, they will mutate over time too, so you always keep successful cell banks so you can keep starting over
In the following study, we will see how scientists use monoclonal antibodies to find a way to neutralize the coronavirus.
The REGN-COV2 antibody Cocktail
Picture above shows antibodies attacking a virus.
The “cocktail” of neutralizing antibodies is called REGN-COV2, and consists of the antibodies REGN10987 and REGN10933. In this case, the antibodies were cloned from human antibodies. This is the first study testing the viability of these antibodies for a COVID-19 treatment.
In this study, two animals are used: the rhesus macaque and the golden hamster. The two naturally have two very different reactions upon infection of the SARS-CoV-2 virus, giving the scientific community a better understanding of the efficacy of this therapy.
Rhesus Macaque : When exposed to the virus, RMs display a transient and mild course of the disease.
Golden Hamster : When exposed to the virus, golden hamsters manifest a very severe form of the disease, accompanied by rapid weight loss and severe lung malformations.
It was interesting and exciting that positive results came out of this study. It showed that there was less viral load in both animals' lower and upper airways as well as a reduction in viral RNA levels. These results show that this therapy could be used to prevent and treat COVID-19.
Of all the therapies cropping up in the past few months, it appears that the use of these neutralizing antibodies have the highest success rate. There are talks surrounding the use of convalescent plasma therapies and mRNA-based vaccines to help end this pandemic. While it appears that vaccination would be the best long term solution, the use of antibodies to completely "cure" COVID-19 infected patients could also be a highly effective solution.
References
Deane, P. (2017, August 22). B cells: The Antibody Factories of the Immune System. Retrieved August 16, 2020, from https://www.lifespan.io/news/b-cells/
Ghose, T. (2020, July 17). What are antibodies? Retrieved August 16, 2020, from https://www.livescience.com/antibodies.html
Baum, A., & Copin, R. (2020, August 3). REGN-COV2 antibody cocktail prevents and treats SARS-CoV-2 infection in rhesus macaques and hamsters. Retrieved August 17, 2020, from https://www.biorxiv.org/content/10.1101/2020.08.02.233320v1
Article Contributors : Edie Whittington, Rahma Osman