Hi. In this video, I'm going to be talking about the innate immune response. So remember the innate immune response is going to be the first response. It's much more simple. But essentially there are 3 components to the innate immune response. The first are chemical and physical barriers, which I'm not going to talk about because they're just kind of common sense. Right? These are the skin, acidic pH of the gut, sort of enzymes, or proteins in the mucus that can degrade bacteria or harm viruses or, you know, get rid of these pathogens before they can actually infect cells and cause harm. So those kind of make sense. Then we have the second response, and these are the cell intrinsic responses. So these are responses that a single cell can do to stop the pathogen. And then finally, you have phagocytic cells. So these are very similar to cell intrinsic responses because usually phagocytic cells are one cell. But usually there are collections of phagocytic cells which go travel around the body and, you know, can be activated and activate other cells to destroy the pathogen. So here's just an example of a blood sample. So you can see the blood cells here. So these little, sort of, donut-looking things are blood cells, but you see all these other things in the cell as well. And these can be part of the innate immune response. They're phagocytic cells, they're white blood cells, they're things that are coming in recognizing pathogens and stopping the infection. The infection. So what happens after the body is presented with some type of pathogen or infection? So after the infection, there are multiple components that come together to initiate the innate immune system response. So the first thing that's really important in the innate immune system response are these things called pathogen-associated molecular patterns. We abbreviate this as PAMPs. So PAMPs are actually sequences, on the infection itself that the host cell recognizes. So a lot of bacteria, some viruses, they have these things called PAMPs, which are very similar across all of one species of bacteria, all of this one class of virus. So the innate immune response, which is not a very specific response, it's kind of just this all-out response, but it can recognize these PAMPs because they're similar on so many different bacteria. And so the things that recognize these PAMPs are called pattern recognition receptors. So these are on the surface of the innate immune system cells, and they can bind to the PAMPs and they say, okay, here's the pathogen. Because our body doesn't have any PAMPs, so if I experience a PAMP, then it must mean that I'm interacting with the bacteria. So an example of this is called the toll-like receptor, this is the most common example that you'll see. And the toll-like receptor or the TLR, when it can bind to a PAMP, this is going to initiate this innate immune response. So signaling is going to be activated, it's going going to activate cells, cells are going to start phagocytosing things, and the innate immune response is going to be really, like highly upregulated. So once the pathogen once the PAMPs are bound to the receptor, this can stimulate the cell to kill the pathogen. It can activate other cells, and eventually lead actually to the adaptive immune system response. But I'll talk about that more in a second. So here we have an example of a Toll-like receptor, You can see Toll-like receptor, TLR4. So if an antigen, say this bacteria, binds this Toll-like receptor, then this can signal all of a bunch of different downstream pathways in the cell. And all of these pathways are immune system components. They're all going to activate the cell to do something to stop this pathogen, either by, you know, initiating phagocytosis, initiating the release of chemicals that will activate other pathways, or the adaptive immune system. And I'm not going to go into the specifics, so you definitely don't need to memorize these pathways or understand, you know, what these abbreviations are. Just understand that some type of pathogen interacts via the TLR, which is a pattern recognition receptor because of the PAMPs that are present on a lot of different bacteria that activates the cell to do a lot of different things. Now, there are other components of the innate immune system that are in addition to these PAMPs being recognized by things like Toll-like receptors. So this includes the complement system. Now the complement system is a collection of around 20 proteins that just always are circling in the blood. Now, if you get an infection, these proteins then become activated and can help get rid of the pathogen. Now, there's a lot of different nuances with the complement system, but I'm going to save that for your immunology classes. But ju
21. The Immune System
The Innate Immune Response
21. The Immune System
The Innate Immune Response - Online Tutor, Practice Problems & Exam Prep
1
concept
Innate Immunity
Video duration:
8mPlay a video:
Video transcript
2
Problem
ProblemWhich of the following is not an innate immune response?
A
The skin barrier
B
Phagocytic cells
C
Complement system
D
Antibody production
3
Problem
ProblemWhat is the name of the pathogenic sequence that a host cell recognizes as foreign?
A
Pattern recognition receptors
B
PAMPs
C
Toll-like receptors
D
Complement sequences