Adaptive Immune Response

by Jason Amores Sumpter
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Hi. In this video we'll be talking about the adaptive immune system, which can mount a specific defense against pathogens. Now the crux of the adaptive immune system will revolve around the interactions between antigens, antigen receptors and antibodies. Those air like the let's call it the three A's of the adaptive immune system. And we've talked about antigens before those air molecules that will produce an immune response and specifically, uh, they will have a region or actually many regions, uh called Tepito pops that are basically parts of the antigen that could be recognized by the immune system and the parts that antibodies and antigens receptors will actually find. And again, you know, an antigen can have many different EP itto pops and different antibodies can, uh, recognize different Pepitone apps on a particular antigen. Now, antibodies are, uh, these why shaped proteins basically that are produced by B cells and will bind to antigens. And you can see that antigen antibody binding happening right there. Now, antigen receptors on B cells at least, are basically just like antibodies. That air stuck in the membrane and you can see a B cell receptor. There looks just like an antibody, except it has a trans membrane domain that is anchoring it in the cell membrane there. Now, T cell receptors are a little different than B cell receptors, and the way I think you should think of them is as if they're just like an arm of a B cell receptors. So, like, imagine this piece right here except stuck in the cell membrane over here. So, you know, here we have the membrane. Uh, it's anchored in right there. And here we have the binding site for the T cell receptor, so that's how I would think of it. And essentially, recognition will occur when B and T cells bind antigens. That's when our adaptive immune system recognizes a pathogen. So Theodore, active immune response has some special features. And that's, you know, that has to do with the fact that it is an antigen specific response and that, uh, it has Teoh be able to process and recognize specific pathogens. I mean, it's so specific that it can actually recognize different strains of the same pathogen and mount different responses to those different strains. So it the specificity just cannot be stressed enough. That's really one of the most important points of the adaptive immune system that it will essentially Onley bind to specific sites on specific antigens, and it mounts these very specific defenses now. It's also super adaptable. The adaptive immune system is really capable of recognizing an almost infinite diversity of antigens. It can, you know, specify itself to essentially, you know, almost anything encounters, obviously, some exceptions, but it's, you know, it's pretty incredible how flexible and adaptable it is. It also includes a type of memory, and this is super important because if you get infected with the pathogen you've already been infected with, your adaptive immune system is going to essentially be able to reactivate itself and mount the previous response that it developed for that pathogen very quickly in full force. And that's why if you get re infected with the pathogen that's already gotten you sick before, you probably won't even notice it because it won't have a chance to, like make you sick. Your adaptive immune system is just so on it now the last point, and you know this is one that's probably less obvious, but super important as well is something that we call self non self recognition essentially the ability of our immune system. Thio recognize the difference between pathogens and the cells of the organism, the self molecules and furthermore Uhh You know the adaptive immune system has thio ensure that you know molecules produced by the organism will never act as antigens. And we're gonna talk about how it does that little later. And here I just have, you know, basically wanted to show you guys the You know, the classic thing that's going on when you think of the adaptive immune system and that is B cells, uh, recognizing pathogens and producing tons of antibodies to combat them. You know, there's other stuff going on that we'll talk about. But, you know, let's say, like the main meat and potatoes is these B cells producing tons of antigens to counter act the infection. So with that, let's flip the page