In this video, we're going to talk more details about how some viruses are able to avoid the immune response by preventing antiviral effects of antiviral proteins or AVPs. First, we need to recall from some of our previous lesson videos what interferons are and what they do. Recall from those older videos that interferons are cytokines that are produced by virally infected cells. When those virally infected cells produce the interferons, neighboring cells produce antiviral proteins or AVPs. Now, the infected cell is initially going to be able to identify the viral RNA via pattern recognition receptors or PRRs inside of the cytoplasm. For example, a RIG-like receptor or a RIG-like PRR is an example of a pattern recognition receptor that can detect viral RNA. Some viruses are able to coat their RNA with a viral protein that basically hides or protects the viral RNA from the cell's cytoplasmic PRRs.
If we take a look at our image down below, we can get a better understanding of this idea. What you'll notice is that we're showing you how some viruses can protect their RNA and block apoptosis in cells. Notice here what we're showing you is a virus that is coming into a host cell. This big blue thing represents our host cell. We have a virus that is infecting the host cell and it uncoats and releases its nucleic acid. It can be transcribed to form viral mRNA. What you'll notice is that in some cases, viral proteins are able to bind and protect the viral RNA. Those viral proteins can protect the viral RNA and prevent RIG-like receptors or RLRs, which are really just pattern recognition receptors that belong to the host, from binding to the viral RNA. Notice that this big red X here represents the fact that the RIG-like receptor is not able to bind to the viral RNA, which means that the viral RNA is able to be translated to create viral proteins.
In addition, once these viral proteins have been made, many of these viral proteins may inhibit or block the process of apoptosis. What you'll notice is the viral proteins are in orange and the host's apoptosis proteins are in green. The viral proteins can bind to the host, apoptosis proteins and prevent apoptosis from occurring. What we need to recall from some of our previous lesson videos, once again, is that antiviral proteins can cause a virally infected cell to immediately go into apoptosis, and apoptosis prevents viral replication. It's in the virus's best interest to prevent apoptosis. Some viruses are able to inhibit the expression of certain genes in the host cell that will prevent apoptosis so that the virus is able to replicate. Once again, that's what we're seeing down below over here on this side. We're showing you how viral proteins can inhibit host apoptosis proteins from triggering apoptosis. This prevents apoptosis from occurring, allowing the virus to be able to replicate.
This concludes our brief lesson on how some viruses are able to avoid the immune system by preventing antiviral effects by using proteins to prevent recognition through PRRs and also using viral proteins to prevent and block apoptosis. We'll be able to get some practice applying these concepts and learn more as we move forward. I'll see you all in our next video.