Using the blood components of a recovered patient to treat or to help one who is recovering. Sounds like a sci-fi technique to save humans, right? Believe me, this technique is at least 100 years old. The very first thought of using the blood of a recovered patient came into the brilliant minds of the physiologists von Behring and Kitasato to treat diphtheria, and they gave it a fair try in 1890.
But its advantage was first observed during Spanish influenza. It lasted almost whooping 3 long years from January 1918 to December 1920. Studies conducted during this pandemic suggest that this therapy could be used as a potential weapon for many of the bacterial and viral infectious diseases.
Later it was found helpful in Cickenpox, management of measles, parvovirus B19 Argentine haemorrhagic fever, influenza, infections by cytomegalovirus, Middle East respiratory syndrome coronavirus (MERS-CoV), H1N1 and H5N1 avian flu, and severe acute respiratory infections (SARI) viruses.
How it works
Plasma, a single largest component of human blood contains water, salts, enzymes, proteins, and antibodies. These antibodies kill the pathogens in the human body. When an infected patient recovers from disease, antibodies that fought the infection are still present in the plasma making that patient immune to that disease for some time. These antibodies could also be an aid to another patient fighting with the same infection.
What is Antibody?
Our adaptive immune system develops a very powerful weapon called an antibody. Humans have more than 10 billion different kinds of antibody. These antibodies are pathogen-specific and need to have exactly opposite shape that of pathogen’s antigen. This right shaped antibody also tells the immune system to make more of this antibody and the immune system produces 2000 antibodies per second.
Pathogens produce some antigens or toxins. Antibodies help our body to identify these antigens on the surface of a microbe. They bind with the antigen of pathogen very specifically, making it inactive. They also mark these antigens alerting the killer cells to kill that pathogen.
In a process called agglutination, a number of antibodies can work together to which makes a number of pathogens stick together. Agglutinated viruses make an easier target for immune cells than single viral particles.
A pathogen-bound antibody binds to Fc receptors, on the surface of phagocytic cells. This also triggers a process called phagocytosis in which phagocytic cells engulfs and destroy the pathogen.