21. Principles of Disease
Viruses Evade the Immune Response
Video duration:
3mRelated Videos
Related Practice
Skip to main content
This video, we're going to talk about another way that some viruses can evade the immune system, and that is by avoiding the effects of antibodies. And so very similarly to bacteria, viruses can also rapidly change their surface structures due to mutations that accumulate in their genome during replication. And so these mutations that accumulate in the viral genome can change its surface structures, And those changes in the surface structures allows the virus to once again evade the adaptive immune response, specifically evading the antibodies. And so some viruses use antibodies to enhance their infection by the process of antibody dependent enhancement, also known as ADE for short. And so viral particles that are bound by antibodies in this process of ADE are engulfed by macrophages where the virus is actually able to actively replicate. And so if we take a look at our image down below over here on the left hand side, we're showing you how some viruses are able to mutate to avoid antibodies. And so notice over here on the left hand side we're showing you our normal virus and this viral, this virus is going to have viral surface proteins. And what you'll notice is that the viral surface proteins over here on the left hand side are pink and, circuit. And notice that through mutations that can accumulate as this virus replicates, the mutations can lead to changes in the surface, molecules of the virus. And so notice now that this virus has new viral surface proteins, and they, the surface proteins have gone from pink circles to being these blue squares. And so, now notice that the antibodies that used to be effective, towards the, circular pink viral proteins are no longer effective towards the, bluish square surface, proteins. And so, by mutating, the virus is able to evade the effects of the antibodies. Now over here on the right hand side, we're also showing you how viruses can actually use antibodies themselves to enter cells in the process of antibody dependent enhancement or ADE. And so, in this image, what you'll notice is that, there is a virus, and the virus is being bound by these antibodies. But these antibodies are actually going to assist with the virus, the virus's replication. And so it turns out that these antibodies will actually enhance the ability for this virus to replicate. And so notice that the virus is saying engulf me, I dare you to the macrophage. And so these antibodies are bound and, it leads to phagocytosis. But notice that this virus is able to evade destruction and it is actually able to replicate inside of the macrophage via this process. And so, again, the virus replicates within the macrophage, invading the antibodies and evading the immune system. And so this here concludes our brief lesson on how some viruses are able to avoid the effects of antibodies in order to evade the immune response. And we'll be able to get some practice applying this as we move forward. So I'll see you all in our next video.
02:13
