WEBVTT - What Are Antibodies, and Why Are We Testing for Them?

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<v Speaker 1>Welcome to brain Stuff production of I Heart Radio. Hey

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<v Speaker 1>brain Stuff, Lauren Bogle bomb here. Antibodies and antibody tests

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<v Speaker 1>have been all over the news lately, so let's talk

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<v Speaker 1>about them. They're part of how your body defends itself.

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<v Speaker 1>But how do they work and why are we testing

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<v Speaker 1>for them? Your immune system is like an entire agency

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<v Speaker 1>in your body that's dedicated to keeping the bad guys

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<v Speaker 1>at bay in order to effectively destroy the enemy or

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<v Speaker 1>antigens as they're called in the immune system BIZ. The

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<v Speaker 1>agency has two arms that ideally work together. The innate

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<v Speaker 1>immune response acts very quickly but without much of a plan,

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<v Speaker 1>and the adaptive immune response is slower but much more

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<v Speaker 1>specific and effective and needs to collect data in order

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<v Speaker 1>to work. Our innate immune response includes a lot of

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<v Speaker 1>initial defensive barriers like your skin and nose hairs, as

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<v Speaker 1>well as a few all purpose weapons like natural killer

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<v Speaker 1>cells or NK cells, which cruise around the body destroying

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<v Speaker 1>cells infected by a virus and keeping an eye out

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<v Speaker 1>for tumors. Our adaptive immune response, on the other hand,

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<v Speaker 1>is the branch of the immune system that learns as

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<v Speaker 1>much about the enemy as possible and creates specialized weapons

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<v Speaker 1>to destroy it. Antibodies are an important tool of the

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<v Speaker 1>adaptive immune response. So what are they? Antibodies are y

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<v Speaker 1>shaped proteins that your immune system makes to help flag

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<v Speaker 1>foreign substances that the body has deemed harmful. Specialized immune

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<v Speaker 1>cells called plasma cells produced them. Plasma cells are activated

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<v Speaker 1>b cells, which is a type of cell that becomes

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<v Speaker 1>activated when one of its receptors recognizes an antigen or

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<v Speaker 1>an enemy and then binds to that enemy. They're then

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<v Speaker 1>poised to create a lot of antibodies for that enemy.

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<v Speaker 1>We spoke by email with Amrat Barber, a professor of

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<v Speaker 1>biology in the Department of Biological and Environmental Sciences at

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<v Speaker 1>Virginia's Longwood University. She explained Antibodies are found in your

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<v Speaker 1>blood and other tissues of your body, and they bind

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<v Speaker 1>to substances that appear foreign and dangerous to your body.

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<v Speaker 1>They are very specific and can recognize and bind to

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<v Speaker 1>many types of pathogens, including viruses, bacteria, fungus, and other

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<v Speaker 1>infectious agents. Your body has billions of antibodies, each recognizing

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<v Speaker 1>a different pathogen, and similar to a key and a lock,

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<v Speaker 1>an antibody is incredibly specific for the pathogen it recognizes,

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<v Speaker 1>so Your immune system has a key on its key

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<v Speaker 1>chain for each and every antigen it's ever fought. When

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<v Speaker 1>an antibody binds to the pathogen that it's specific for,

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<v Speaker 1>it acts as a flag to alert the immune system

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<v Speaker 1>that this antigen is dangerous and should be destroyed. The

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<v Speaker 1>antibody then works with other proteins and cells in your

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<v Speaker 1>immune system to slow the infection and clear the pathogen

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<v Speaker 1>from your body. A vaccine is made of defunct antigens

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<v Speaker 1>that show your immune system what the enemy looks like,

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<v Speaker 1>so that it can begin making antibodies to defend itself

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<v Speaker 1>against the pathogen before it's ever been exposed to the

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<v Speaker 1>real thing. Though, specific antibodies can sometimes wane and disappear,

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<v Speaker 1>which is why vaccine boosters are sometimes necessary. So that's antibodies,

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<v Speaker 1>But how do antibody tests work. An antibody test shows

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<v Speaker 1>whether a person's immune system has made antibodies against the

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<v Speaker 1>infection that's being tested for. If a person has been

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<v Speaker 1>exposed to a pathogen take the COVID nineteen virus, for instance,

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<v Speaker 1>then there be cells will become activated and start making

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<v Speaker 1>antibodies specific for that virus. But as good as antibodies

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<v Speaker 1>aren't their job. There's always a little lag time with

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<v Speaker 1>this process. It can take a week or two for

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<v Speaker 1>a person to start making antibodies against an infection with

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<v Speaker 1>particularly nasty pathogens like measles or even COVID nineteen. In

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<v Speaker 1>some cases, the disease might kill the person before their

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<v Speaker 1>immune system has time to develop antibodies against it. Barbara explained.

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<v Speaker 1>During an antibody test, a person's blood is analyzed to

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<v Speaker 1>see if it contains antibodies that bind to the virus.

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<v Speaker 1>It does not determine if someone has an active infection,

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<v Speaker 1>but whether they're making antibodies to the pathogen. A positive

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<v Speaker 1>antibody test suggests that the person was exposed to the pathogen.

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<v Speaker 1>In essence, an antibody test indicates that a person's body

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<v Speaker 1>has mounted an immune response against a specific pathogen at

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<v Speaker 1>some point, but what it can't tell is whether the

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<v Speaker 1>person is currently infected with that pathogen. There are different

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<v Speaker 1>types of antibodies for particular pathogens. Some indicate recent infection

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<v Speaker 1>and summer signs of older infection. Antibody testing means testing

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<v Speaker 1>for all of the different types. If you want to

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<v Speaker 1>look for a recent COVID nineteen infection, you'd test for

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<v Speaker 1>immunoglobin M antibodies. Immunoglobin G antibodies, on the other hand,

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<v Speaker 1>take longer to produce, so would indicate older infection. Current

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<v Speaker 1>COVID nineteen antibody testing can and does detect both types,

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<v Speaker 1>So a positive antibody test indicates that you have antibodies

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<v Speaker 1>in your blood that recognize and react with that specific pathogen,

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<v Speaker 1>which is a strong indicator that these antibodies would likely

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<v Speaker 1>provide immunity for some amount of time. In the case

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<v Speaker 1>of COVID nineteen, it's difficult to know at this point

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<v Speaker 1>for how long those antibodies can protect you from reinfection,

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<v Speaker 1>or even whether they can at all. Barbera said the

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<v Speaker 1>length of protection depends on a lot of factors, including

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<v Speaker 1>how much antibody a person makes and whether the virus mutates.

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<v Speaker 1>That said, antibody tests can be used not only to

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<v Speaker 1>determine if a person has been infected with COVID nineteen,

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<v Speaker 1>but also to gain a better understanding about how widespread

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<v Speaker 1>COVID nineteen is within a given community. For instance, people

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<v Speaker 1>who are infected with COVID nineteen but experienced relatively mild

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<v Speaker 1>symptoms will still test positive on an antibody test in

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<v Speaker 1>the same way as someone with a very acute case.

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<v Speaker 1>Barbara said, if antibody testing is conducted on a large scale,

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<v Speaker 1>the results can be used to more accurately estimate how

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<v Speaker 1>many people were exposed to the virus. Antibody tests will

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<v Speaker 1>also likely play a large role in getting life back

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<v Speaker 1>to normal. People with positive antibody tests will be able

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<v Speaker 1>to show that they developed immunity to the virus and

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<v Speaker 1>thus are protected from reinfection at least for an extended

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<v Speaker 1>amount of time. But Barbara warns that antibody test results

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<v Speaker 1>should be taken with a grain of salt, as people

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<v Speaker 1>who test positive may still have an active virus that

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<v Speaker 1>they could spread to others. Therefore, the use of a

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<v Speaker 1>test that tests for the presence of the actual virus,

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<v Speaker 1>paired with an antibody test for COVID nineteen would give

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<v Speaker 1>a more accurate picture of whether a person is safe

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<v Speaker 1>to return to normal life. Today's episode was written by

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<v Speaker 1>Jesscelyne Shields and produced by Tyler Klang. For more on

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<v Speaker 1>this and lots of other topics, because it houstof works

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<v Speaker 1>dot com. Brain Stuff is production of iHeart Radio. For

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