20. Adaptive Immunity
Outcomes of Antibody Binding to Antigen
Outcomes of Antibody Binding to Antigen
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So we know that antibodies play a huge role in adaptive immunity. But how exactly do antibodies protect us from pathogens? Well in this video we're going to talk about some of the possible outcomes of antibody binding to antigen. So once antibodies are secreted from plasma cells and bind to their very specific antigens, those antibodies can result in many possible outcomes that protect us from pathogens and provide immunity. And so notice that number down below one through six, we have a few of the possible outcomes of antibody binding to antigen. Now, the term serology is a term that refers to the scientific study of blood serum, especially the blood serums antigen antibody reactions. And so once again, number down below, we have six of the possible antigen antibody reactions. And so notice the very first one that we have here is a recall because we've discussed this before in some of our previous lesson videos and that is that antigen antibody reactions can lead to optimization. Which recall is a process that makes microbes significantly easier to bind and engulf during Figo psychosis, allowing fabio sites to bind to the microbes and engulf them in a fake ghost toast them much much easier. And so each of these numbers that you see in the text up above, correspond with the numbers that we have down below in our image. And so if we take a look at number one in our image, notice that we're showing you optimization when antibodies bind to antigens on microbes for example, uh those antibodies can allow for optimization improved to go psychosis by tego sites such as macrophages. And so notice that this macrophages able to easily fabio santos, this microbe and digest and eliminate that microbe thanks to the antigen antibody reaction. Now, the second possible outcome that we have is that antibodies can prevent the adherence of microbes to host cells. And antibodies can also immobilize microbes. And so when antibodies bind to antigens again, they can block those antigens from interacting with the host cells and causing them harm. And or the antibodies can bind to pathogens and mobilize them, meaning that they can prevent them from moving in their environments. And ultimately that will help prevent the infection of host cells. And so if we take a look at our image down below at number two notice that we're showing you uh the immobilization um as well as the prevention of adherence that antibodies can provide. And so when these antibodies, these y shaped proteins here bind to microbes like this blue one here, they can block that microbes interaction with host cells and in some cases that can prevent those pathogens from causing us harm. Also, antibodies can bind to structures on the surface of pathogens that can immobilize them such as binding to their flag ela and preventing those microbes removing about in their environments, which can ultimately help prevent those microbes from causing us harm. Now the third possible outcome that we have here is also a recall because we've also talked about this in our previous lesson videos and that is that antibodies binding to antigens can lead to activation of the complement system or complement system activation. And recall that the activation of the complement system is going to occur via the classical pathway whenever antibodies are involved. And so if we take a look at our image down below at number three notice that we're showing you complement system activation again via the classical pathway. And so notice that here we have these antibodies binding to these specific antigens on these microbes and that can lead to the activation of the complement system, activating several complement proteins and ultimately that will lead to um some innate effect our actions such as inflammation optimization and sell license. And so if you don't remember much about the complement system or the classical pathway, be sure to go back to our older lesson videos to check those out. So the fourth possible outcome that we have is that antibodies can neutralize toxins and viruses so they can lead to toxin or virus neutralization. And so when antibodies bind to toxins and again viruses, uh they can make those toxins and viruses ineffective and harmless again helping to protect us and provide immunity. And so if we take a look at number four notice that we're showing you toxin and virus neutralization here And so notice that we have the toxin is and red and we have the virus over here in the screen. And so notice that we have antibodies binding to the toxin again neutralizing that toxin making it ineffective and harmless. And over here we have a virus and notice that the antibodies are binding to the virus. Again potentially making this virus ineffective and harmless. Now the 5th fifth possible outcome that we have of antigen binding to uh antibodies binding the antigens is a glutinous nation and a glut in ation is really just a fancy scientific word for clumping. And so antibodies actually have multiple antigen binding sites. And occasionally these antibodies can bind to multiple um antigens, multiple different antigens and can lead to what is known as cross linking and can cross link separate antigens essentially clumping those antigens together so that those antigens are all relatively in the same location and that makes them a lot easier to fake ghost toast in large groups and eliminate pathogens in larger groups. And so if we take a look at our image down below notice at number five over here we're showing you a glutinous nation, which again is just a fancy scientific word for clumping. And so you can see the cross linking of microbes for fabio psychosis. And again notice that a single antibody is capable of binding to multiple different antigens. And so notice that this single antibody is cross linking this microbe with this other microbe over here because it's being it's bound to both of them. And so it will help clump these microbes together uh so that these foreign invaders can all be targeted for destruction and eliminated together as a group, making uh immunity and protection more effective. And then last but not least, the six possible outcome that we have listed here of antibodies binding antigens is that uh antibodies can lead to what is known as antibody dependent cell mediated cida toxicity which is commonly abbreviated as A D. C. C. And so antibody dependent cell mediated side of toxicity or A D. C. C. Um is really just a process that allows natural killer cells or NK cells to target and kill antibody bound infected host cells. And so we'll be able to talk more details about this process here a DCC later in our course as we move forward. And we'll also get to talk more about natural killer cells as well as we move forward as well. But if we take a look at our image down below at number six, notice that we're showing you antibody dependent cell mediated side of toxicity or a DCC and notice that we have an an infected host cell over here in green and this infected host cell is going to be bound by antibodies. And so when these antibodies bind to the infected host cell, natural killer cells can detect that and release death signals to trigger the infected cell to undergo apoptosis, which ultimately helps to eliminate the pathogen uh and eliminate the infected cell to help provide us immunity. And so this year concludes our brief lesson on some of the possible outcomes of antibody binding to antigen. And we'll be able to get some practice applying these concepts as we move forward in our course. So I'll see you all in our next video.
Which term describes antibodies binding to a virus preventing it from attaching to host cells?
The study of antigen-antibody reactions is referred to as _____.
Which of the following is NOT a protective outcome of antibody-antigen binding?
Antibody-antigen complex triggering the complement system when bound to an antigen.
Antibodies cross-linking pathogens so that they can be easily phagocytosed by macrophages.
Antibodies signaling to a cytotoxic T cell that a host cell is infected.
Antibodies binding to bacteria and prevent the bacteria from moving throughout the body.
Antibodies binding to blood vessel walls resulting in vasodilation.