Welcome to brain Stuff production of I Heart Radio. Hey brain Stuff, Lauren Bogle bomb here. Antibodies and antibody tests have been all over the news lately, so let's talk about them. They're part of how your body defends itself. But how do they work and why are we testing for them? Your immune system is like an entire agency in your body that's dedicated to keeping the bad guys at bay in order to effectively destroy the enemy or antigens as they're called in the immune system BIZ. The
agency has two arms that ideally work together. The innate immune response acts very quickly but without much of a plan, and the adaptive immune response is slower but much more specific and effective and needs to collect data in order
to work. Our innate immune response includes a lot of initial defensive barriers like your skin and nose hairs, as well as a few all purpose weapons like natural killer cells or NK cells, which cruise around the body destroying cells infected by a virus and keeping an eye out for tumors. Our adaptive immune response, on the other hand, is the branch of the immune system that learns as much about the enemy as possible and creates specialized weapons
to destroy it. Antibodies are an important tool of the adaptive immune response. So what are they? Antibodies are y shaped proteins that your immune system makes to help flag foreign substances that the body has deemed harmful. Specialized immune cells called plasma cells produced them. Plasma cells are activated b cells, which is a type of cell that becomes activated when one of its receptors recognizes an antigen or
an enemy and then binds to that enemy. They're then poised to create a lot of antibodies for that enemy. We spoke by email with Amrat Barber, a professor of biology in the Department of Biological and Environmental Sciences at Virginia's Longwood University. She explained Antibodies are found in your blood and other tissues of your body, and they bind to substances that appear foreign and dangerous to your body.
They are very specific and can recognize and bind to many types of pathogens, including viruses, bacteria, fungus, and other infectious agents. Your body has billions of antibodies, each recognizing a different pathogen, and similar to a key and a lock, an antibody is incredibly specific for the pathogen it recognizes, so Your immune system has a key on its key
chain for each and every antigen it's ever fought. When an antibody binds to the pathogen that it's specific for, it acts as a flag to alert the immune system that this antigen is dangerous and should be destroyed. The antibody then works with other proteins and cells in your immune system to slow the infection and clear the pathogen
from your body. A vaccine is made of defunct antigens that show your immune system what the enemy looks like, so that it can begin making antibodies to defend itself against the pathogen before it's ever been exposed to the real thing. Though, specific antibodies can sometimes wane and disappear, which is why vaccine boosters are sometimes necessary. So that's antibodies, But how do antibody tests work. An antibody test shows whether a person's immune system has made antibodies against the
infection that's being tested for. If a person has been exposed to a pathogen take the COVID nineteen virus, for instance, then there be cells will become activated and start making antibodies specific for that virus. But as good as antibodies aren't their job. There's always a little lag time with this process. It can take a week or two for a person to start making antibodies against an infection with
particularly nasty pathogens like measles or even COVID nineteen. In some cases, the disease might kill the person before their immune system has time to develop antibodies against it. Barbara explained. During an antibody test, a person's blood is analyzed to see if it contains antibodies that bind to the virus. It does not determine if someone has an active infection,
but whether they're making antibodies to the pathogen. A positive antibody test suggests that the person was exposed to the pathogen. In essence, an antibody test indicates that a person's body has mounted an immune response against a specific pathogen at some point, but what it can't tell is whether the person is currently infected with that pathogen. There are different types of antibodies for particular pathogens. Some indicate recent infection
and summer signs of older infection. Antibody testing means testing for all of the different types. If you want to look for a recent COVID nineteen infection, you'd test for immunoglobin M antibodies. Immunoglobin G antibodies, on the other hand,
take longer to produce, so would indicate older infection. Current COVID nineteen antibody testing can and does detect both types, So a positive antibody test indicates that you have antibodies in your blood that recognize and react with that specific pathogen, which is a strong indicator that these antibodies would likely provide immunity for some amount of time. In the case of COVID nineteen, it's difficult to know at this point for how long those antibodies can protect you from reinfection,
or even whether they can at all. Barbera said the length of protection depends on a lot of factors, including how much antibody a person makes and whether the virus mutates. That said, antibody tests can be used not only to determine if a person has been infected with COVID nineteen, but also to gain a better understanding about how widespread
COVID nineteen is within a given community. For instance, people who are infected with COVID nineteen but experienced relatively mild symptoms will still test positive on an antibody test in the same way as someone with a very acute case. Barbara said, if antibody testing is conducted on a large scale, the results can be used to more accurately estimate how many people were exposed to the virus. Antibody tests will also likely play a large role in getting life back
to normal. People with positive antibody tests will be able to show that they developed immunity to the virus and thus are protected from reinfection at least for an extended amount of time. But Barbara warns that antibody test results should be taken with a grain of salt, as people who test positive may still have an active virus that
they could spread to others. Therefore, the use of a test that tests for the presence of the actual virus, paired with an antibody test for COVID nineteen would give a more accurate picture of whether a person is safe to return to normal life. Today's episode was written by Jesscelyne Shields and produced by Tyler Klang. For more on this and lots of other topics, because it houstof works
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