Interferon Response - Video Tutorials & Practice Problems
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Interferons
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In this video, we're going to begin our introduction to the Interferon response. And so first, we need to recall from some of our previous lesson videos that interferons are commonly abbreviated as ifns. And these interferons are one of many different types of cytokines or chemical signals used to communicate between cells. And so these interferons are specifically cytokines that provide anti viral effects or in other words, it helps to provide defense against viruses and it will provide these anti viral effects to neighboring cells. And so we'll be able to talk more detail about the steps of the interferon response in our very next lesson video. But for now, if we take a look at our image down below, notice, we're showing you our map of the lesson on innate immunity. And right now here in this video, we're focusing in specifically on the second line of defense on the innate effector actions, specifically the interferon response. And so once again, in our next lesson video, we'll get to talk a lot more details about this interferon response in order to understand how it allows for anti viral effects. And so I'll see you all in our next video.
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Steps of the Interferon Response
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In this video, we're going to talk more details about the steps of the interferon response, which recall from our last lesson video provides antiviral effects or defense against viruses in neighboring cells. Now, before we begin, I want to first mention that the text that you see up above uh corresponds with the image that you see down below on the interferon response. And so one thing that we're going to do as we break this up is we're going to go uh from the text up above uh down to the image down below. So you can see how it corresponds. And so here, what we're saying is that when the Pr Rs or the pattern recognition receptors of an infected cell detect viral RN A sometimes that infected cell can produce and secrete interferons which recall interferons are commonly abbreviated as ifns. And so, uh if we take a look at our image down below, on the left hand side over here, uh notice that we're showing you uh uh our first cell and this first cell is being infected by a virus. And so notice that this is our virus and notice that the virus here is infecting this uh cell that we have right here. And so uh the the the virus is infecting the cell. However, this infected cell uh is sometimes able to create interferons. And so notice that this cell, although it is being infected, it is producing and secreting these interferon molecules and the interferon molecules can uh again, be produced by the first cell and diffuse over towards neighboring cells. And so again, uh what we're saying here is that the infected cell can produce and secrete interferons. And those interferons can go on to diffuse to a neighboring cell and bind to that neighboring cell in order to warn that neighboring cell of the presence of the virus. And so notice here uh in the image, uh we have these little interferon molecules diffusing over to a neighboring cell here that has not yet been infected by the virus. Now notice this uh little bubble speech that's being said here by the first cell. Uh that is infected. Notice that because this cell here is being infected by the virus. Uh It's saying I'm doomed. And so this first cell uh although it is being infected by the virus and it is ultimately going to be killed by the virus. Um It's saying here that maybe I can save my neighbors if I release interferons. And so the first cell, although it knows it is going to die by the virus, it can release these interferons again to warn neighboring cells of the presence of the virus before the virus actually gets over to it. And so again, here, what we're saying is that these interferons that have been released by the first infected cell, they can uh diffuse over towards neighboring cells and bind to those neighboring cells that have not yet been infected. And when the interferons bind to those neighboring cells that have not yet been infected, it can actually lead to the production of inactive antiviral proteins or IAVPS in those neighboring cells that have not yet been infected. And so if we take a look at our image down below, notice that these interferons that have diffused over to the neighboring cell over here allow for the production of IAVPS inactive antiviral proteins. And so notice it says here that the neighboring cell receives the interferons. It detects the interferons and the detection of the interferons allows the neighboring cell to produce those Iavps inactive antiviral proteins. Now, these inactive antiviral proteins, as their name implies, they are inactive. And so because they are inactive, they are not going to do anything until they become activated. Uh however, they are being expressed. So they are ready to uh take action and become activated when the scenario presents itself. And so notice that this bubble speech over here by the neighboring cell is saying, oh, I just got a message and the message is referring to the interferons that my neighbor was infected by a virus. So I better make these anti viral proteins or IAVPS. Now, if this neighboring cell down the line is ever infected by that virus, then the detection of that viral double stranded RN A or just any type of viral RN A that is detected that can actually activate that neighboring cells inactive antiviral proteins. And the activation of inactive antiviral proteins will form a VPs, active viral uh active antiviral proteins and these active uh antiviral proteins or a VPs, they have the ability to stop translation of the cell by degrading the cell's MRN A. And uh ultimately, this will trigger apoptosis. And although apoptosis is programmed cell death, that will kill the cell, it is also going to prevent, it will also prevent the virus from using the cell as a host to replicate. And so ultimately, it will prevent the virus replication. And so if we take a look at our image down below, notice that the first cell over here that is infected by the virus, again, it releases those interferons so that the neighboring cell can respond to those interferons. However, the first cell uh again, uh the infected cell is going to ultimately die. It will produce new viruses. So more viruses will be uh produced. And uh again, the infected cell here is going to lice so it is going to die. However, uh by releasing the interferons, the first infected cell is making an effort to help uh control the replication of the virus by um allowing for anti viral proteins to be produced. And so notice that later down the line, if this virus ever tries to make an attempt to infect this neighboring cell, this neighboring cell has these inactive antiviral proteins and the neighboring cell, if it is ever infected by the virus, the um the inactive antiviral proteins, the IAVPS are able to activate into a VPs. And so notice that the bubble speech here in the neighboring cell is saying, hey, uh sorry virus um that I, I'm, I know you're trying to infect me, but you're not going to use me to replicate. I'm going to sacrifice myself by performing apoptosis so that your replication cycle ends here. And so notice it saying IAVPS or inactive A VPs activate into a VPs. And so you can see the iavps here are activating into a VPs and um the A VPs can trigger apoptosis. And so notice that the cell here is performing apoptosis and notice it's saying I might be dead. But so are you virus? And so because this cell performs apoptosis, it prevents the replication of the virus. And so, whereas the first cell over here produced many uh copies of the virus, the second cell did not produce any copies of the virus. And so this helps to prevent um the replication of the virus and to limit the replication of the virus. And so notice down below what we're saying, is thanks to this interferon response, the virus is unable to replicate in the neighboring cell because the neighboring cell was uh prompted to produce antiviral proteins. And so, uh by preventing the replication of the virus, this is a great step in preventing the spread of the virus. And uh it is going to allow for uh the buying of more time to ultimately eliminate the virus from our bodies and to uh again, get rid of the virus. And so this interferon response again is an anti viral uh response that helps protect neighboring cells from viruses and ultimately help uh limit the replication of a virus. And so, uh notice here in summary, the interferon's function is to prevent or limit viral replication by warning neighboring cells to build antiviral proteins. And so this here concludes our lesson on the steps of the interferon response and its antiviral effects. And we'll be able to get some practice applying these concepts as we move forward in our course. And so I'll see you all in our next video.
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Problem
Problem
How does the interferon response provide anti-viral protection?
A
Interferons bind to the virus neutralizing it.
B
Interferons stimulate neighboring cells to produce anti-viral proteins.
C
Interferons prevent the virus from entering the cell.
D
Interferons prevent the virus from leaving the infected cell and infecting neighboring cells.
4
Problem
Problem
If a cell produces antiviral proteins (AVPs) what occurs when that cell encounters dsRNA?
A
The antiviral proteins trigger the production of iAVPs.
B
The antiviral proteins cease protein translation in the cell so no viral proteins can be made.
C
The antiviral proteins become activated and the cell undergoes apoptosis to stop the viral spread.
D
The antiviral proteins trigger the production of interferon proteins to warn neighboring cells of viral infection.
5
Problem
Problem
How does the interferon response to an invading virus result in the infected cell undergoing apoptosis?
A
Detection of viral RNA triggers the degradation of host RNA and stops translation which results in cell death.
B
Detection of viral proteins inactivates the AVPs which triggers cells death.
C
Detect of viral RNA ceases all functions of the cell and results in cell lysis and release of newly made viruses.
D
Detection of viral proteins causes pores to form in the surface of the cell resulting in apoptosis.
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Problem
Problem
Which of the following cells can induce viral-infected cells to undergo apoptosis?
A
Neutrophils.
B
NK cells.
C
Eosinophils.
D
B cells.
E
Basophils.
F
Red blood cells.
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Problem
Problem
Which of the following statements about interferon is incorrect?
A
It only works on enveloped viruses.
B
It decreases the spread of the virus.
C
It is a species-specific molecule.
D
It does not directly inactivate viruses.
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