Classes of Antibodies - Video Tutorials & Practice Problems
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1
concept
Classes of Antibodies
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In this video, we're going to talk about the different antibody classes. And so it turns out that there's actually five different classes of antibodies or in other words, five different classes of immunoglobulins. And so these five classes are based on differences in their heavy chains as we'll see down below in our table. And so the five classes of antibodies are iggigaigmigenigd. And if you look at these red letters here, notice that it spells gamed and so notice down below right here, we have this antibody stick figure playing some video games and based on his facial expression, I'd say he's pretty gamed out from playing video games for 72 hours straight. And so hopefully this antibody stick figure along with gamed will help you guys remember the five different classes of antibodies. And so looking at this table right here, what I want you guys to notice is that uh the light chain for all five classes of antibodies is exactly the same. So the light chain will either be the one that's represented by the Greek letter Kappa or the light chain represented by the Greek letter lambda. And so the light chain is not going to distinguish one antibody class from another. However, looking at the heavy chain, notice that each class of antibody has a unique heavy chain. And so it's the heavy chain that's going to distinguish one antibody from uh one antibody class from another. And so this first row of uh antibody, this first class of antibody is IgG and this is really the one that we've been talking about all along. And so you can see the Y shaped structure here that we talked about. Now notice that IgE and IgD have very similar type of structures to IgG. However, IG A forms a dimer of these two Y shaped structures. And IgM tends to form a pener uh containing five different Y shaped structures here. Now, uh over here in this column, what we have is the primary feature of each of these antibodies. Now IgG is actually the most prevalent and the most abundant antibody in our blood. So this is going to be one that's involved uh and protecting pretty much against all types of infections including bacterial and viral infections. Now IG A is actually going to be highly concentrated in mucus membranes and it's going to be one that is uh typically secreted by ourselves and um it's also prevalent in our saliva. Now, IgM interestingly enough is usually going to be the first antibody uh that's going to be produced upon infection. So, uh IgM is going to be the one that's going to initiate the primary immune response. So the very first immune response and then, uh, the common second immune response would be IgG since it's so prevalent in our blood. Now, IgE, on the other hand, here is going to be one that's going to defend against allergies or allergens. And so you can see here, we have a guy who's saying I'm allergic to this kitty cat right here. And that's unfortunate because this is a cute little kitty cat, but IgE again, is gonna help defend against these allergens. Now IgD is one where its function is not really very well characterized. Uh However, there are some of uh textbooks and studies that say they're involved with activating B cells and uh allowing B cells to uh participate in immune responses. Now, over here on the far, right, what we have is the distribution of these antibodies uh classes throughout our bodies. And so notice that pretty much all of the antibodies are gonna be found in our bloodstreams uh except for IG A which again is gonna be highly concentrated in our mucus membrane. So it's gonna be lining our uh digestive systems a lot. And so this here concludes our introduction to the antibody classes and we'll be able to talk more about antibodies as we move along in our course. So I'll see you guys in our next video.
2
Problem
Problem
Which of the following is NOT an immunoglobin class?
A
IgM.
B
IgH.
C
IgG.
D
IgE.
E
IgD.
3
concept
IgG
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3m
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In this video, we're going to talk more details about the IgG class of antibody. And so the IgG antibody is the standard antibody. And that is because the IgG antibodies are the most abundant antibody class in our blood and in our tissues. And in some individuals, the IgG antibodies can make up to 80% of all of the immunoglobulins. Now, these IgG antibodies can have a variety of different functions. However, they are capable of binding to very specific antigens and they can eliminate pathogens by activating the complement system classical pathway which recall we covered the complement system classical pathway in our previous lesson videos, when we discussed innate immunity. Now IgG antibodies are also well known for providing immunity to a developing fetus during pregnancy as well as providing immunity to a newborn child after the child has been born. And so this is because these IgG antibodies have the amazing ability to cross the placenta between a mother and the baby. And so the mother's IgG antibodies are capable of crossing the placenta to protect the baby. So literally the mother is protecting the baby with her antibodies. Now, also IgG antibodies are well known for having a long half life. And all that means is that uh if it has a long half life is that it's very, very stable and it is capable of lasting a long time within our bodies before it's broken down. And so this long half life actually extends the time of protection of a newborn uh through the first few months after birth until the baby is capable of generating its own antibodies. And so basically, what we're saying here is that literally a mother's antibodies protects the baby as the baby is a developing fetus. And for the first few months of the baby's life until the baby is capable of generating its own antibodies. And so if we take a look at our image down below, it's just an image emphasizing those important features of the IgG class of antibody. And so notice that its structure is gonna be that standard antibody structure that we talked about in our previous lesson. Videos. Notice it is the most abundant class of antibodies. Around 80% of the antibodies are gonna be IgG, it provides infant immunity during again pregnancy as well as after childbirth as well because the IgG antibody has that amazing ability to cross the placenta between the mother and baby. And last but not least, this IgG antibody has many different immune functions, including uh the ability to activate the complement system via the classical pathway where it can bind to antigens. And again, uh you can see uh activating C three conversion taste leading to many different types of compliment system uh activity such as inflammation, optimization, cell lic of microbes and so on. And again, if you don't remember these details here about the complement system classical pathway, be sure to go check out our older lesson videos on that content. But for now, this year concludes our brief lesson on the IgG class of antibodies. And as we move forward in our course, we'll also be able to discuss briefly some of the other classes of antibodies. So I'll see you all in our next video.
4
concept
IgA
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2m
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In this video, we're going to briefly discuss the IG A class of antibody. And so the IG A class of antibody is going to help protect mucus membranes throughout our bodies. And they can also be found in body secretions such as for example, saliva, tears and breast milk. Now, the IG A antibody is commonly found as a dimer, which means that it consists of two identical subunits that are held together. And this dimer is uh referred to as secretory IG A or SI G A for short and within the secretory ig A uh molecule, which is a dimer. It consists of two monomers that are held together by a peptide. And we'll be able to see that down below in our image. Now, the secretory ig A antibody in breast milk helps protect the intestinal tract of breastfed newborns, which is why breastfeeding can actually be very healthy for newborn babies to provide them with those IG A antibodies that can help protect again the intestinal tract of those newborns. And so if we take a look at our image down below, we're just emphasizing those same important details of the IG A antibody and Uh again, the IG A antibody is commonly found as a dimer that we refer to as secretory IG A. And so, what you can see here is that there is a dimer, there's uh this unit right here and then there's this uh other identical unit right here. And these two units are held together by this blue peptide that is swirling around it. And so, uh that is the secretory ig a antibody. Again, this is really going to be important for protecting mucous membranes uh throughout our bodies. And also it's gonna be found in uh mucus saliva, tears and breast milk. And so you can see those images down below. And again, because it is found in breast milk, it will help protect the intestinal track of newborn babies that are breastfed. And so you can see the IG A antibody here uh dissolved within this breastmilk. And so uh this here concludes our brief lesson on the IG A class of antibody. And again, we'll be able to get some practice applying these concepts and talk about the other classes of antibodies briefly as we move forward. So I'll see you all in our next video.
5
concept
IgM
Video duration:
3m
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In this video, we're going to briefly discuss the IgM class of antibody. And so the IgM antibody is very important for controlling infections in the blood. And it is actually the very first antibody that is going to be initially produced in a primary infection by plasma cells before a process known as class switching takes place. And later in our course, in a different video, we'll talk more about this antibody class switching. Now, the IgM class of antibody is also the largest class of antibody in terms of its size and molecular mass. Because IgM antibodies consist of a pimer, which means that it is composed of five identical y shaped subunits. And because it has five y shaped subunits each sub unit with two antigen binding sites, that means that there are 10 antigen binding sites. And because there are so many antigen binding sites on these IgM antibodies that makes them very, very effective at linking antigens together. Now, the large size of the IgM antibody class actually prevents the IgM antibody from uh leaving the blood uh into the tissues. And so that's why the IgM antibody, its primary role is to help control infections in the blood. Also the IgM uh class of antibody is the most efficient antibody class at activating the complement system via the classical pathway. And so if we take a look at our image down below, once again, we'll have an image that helps to emphasize those same features of the IgM class of antibody. Notice first that it is indeed a pener that consists of these five identical y shaped subunits. And so uh that it makes it the largest antibody class. So we can label it here as the largest antibody class in size. Also, it is the very first antibody that is initially created by all plasma cells prior prior to the antibody class switching process that we'll get to talk about in more detail later in our course. And the primary role of the IgM antibody because of its large size is to control infections in the bloodstream. Uh Also this is the most effective antibody at activating the complement system. So it activates the complement system when it binds to the antigen. And again, here we have a little image that shows you uh C three converse being uh generated uh upon activation of the complement system. And then all of these um uh actions that result from the complement system activation, including information optimization and cell lic of microbes. And again, if you don't remember much about the complement system, make sure to go back to our older lesson videos to check those out. But again, this year concludes our brief lesson on the IgM class of antibody. And we'll be able to get some practice applying these concepts and talk about the other classes as we move forward. So I'll see you all in our next video.
6
concept
IgE
Video duration:
2m
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In this video, we're going to talk briefly about the IgE class of antibody. And so, the IgE antibodies are found on the surface of both basophils and mass cells. And recall that basophils and mass cells are uh going to have a lot of similarities. Uh but recall that basophils will circulate through the bloodstream, whereas mass cells are more localized within specific tissues. And so, uh when these IgE antibodies are on the surface of basophils and mass cells, they're capable of detecting and responding to very specific antigen. And these IgE antibodies can actually cause the cell to undergo a process called degranulation, which you might recall from some of our previous lesson videos just means that it will cause these cells to release their Granules and the contents of their Granules into the environment. And so uh that can include releasing inflammatory mediators that lead to inflammation in response to some kind of infection. Now, uh these IgE antibodies are very important for eliminating parasites such as worms. And they're also going to play an important role in the response to many different types of allergic reactions or hypersensitivities, which we'll get to talk more about allergic reactions and hypersensitivities much later in our course in a separate video. Uh But for now, if we take a look at our image down below, we can get uh a more solid understanding of this IgE class of antibody. And notice here, it has that same antibody structure. And again, it's found on the surface of both basophils uh as well as mass cells. And so you can see uh the basophil over here, the mass cells over here and upon binding their antigen, they cause degranulation, uh the release of the contents of the cytoplasmic Granules, which could include inflammatory mediators leading to inflammation. And so this can uh these IgE antibodies are important for protecting against parasitic infections like uh those parasitic worms as well as again, responding to uh allergies or uh generating those allergic reactions. And again, we'll get to talk more about allergies uh later in our course. But for now, this year concludes our brief uh lesson on the IgE class of antibody. And we'll be able to get some practice applying these concepts and then talk about the very last class of antibodies. So I'll see you all in our next video.
7
concept
IgD
Video duration:
1m
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In this video, we're going to talk very briefly about the IgD class of antibody. And so IgD antibodies are found on the surface of B cells and they signal B cell activation and maturation into an antibody secreting plasma cell. And so really, these IgD antibodies are important for the development and maturation of the antibody response. And so if we take a look at our image down below, we can see here that the IgD antibody is again a monomer that you can see here that makes up a very small percentage of all of the antibodies, about 1% of all the antibodies. And again, it's going to be found uh it can be found on the surface of B cells as you see here. And uh their role uh on the surface of B cells is again to help uh the B cell differentiate into plasma cells that can secrete antibodies. And so the IgD antibody is going to help activate the B cell and help it differentiate into a plasma cell. And uh ultimately, the plasma cell will be able to secrete uh a variety or um uh different types of antibodies. And so this here concludes our brief lesson on the IgD antibody and its role in the development and maturation of the antibody response. And we'll be able to get some practice applying this as we move forward. So I'll see you all in our next video.
8
Problem
Problem
______ is the first immunoglobulin class produced during a primary response.
A
IgA.
B
IgE.
C
IgM.
D
IgG.
9
Problem
Problem
Which antibody class crosses the placenta from mother to child?
A
IgA.
B
IgE.
C
IgM.
D
IgG.
10
Problem
Problem
_______ is the immunoglobulin class that neutralizes viruses in the intestinal tract.
A
IgG.
B
IgA.
C
IgD.
D
IgE.
11
Problem
Problem
Which of the following antibodies is involved in causing basophils to release histamine when the antibody encounters an allergen?
A
IgG.
B
IgA.
C
IgD.
D
IgE.
12
Problem
Problem
The primary B-cell receptor is:
A
IgD.
B
IgA.
C
IgE.
D
IgG.
13
concept
Review Table of Immunoglobin Classes
Video duration:
3m
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In this video, we're going to do a quick review of all of the immunoglobulin classes or all of the classes of antibodies. And so we're gonna do that by completing this review table of the immunoglobulin classes. And so uh what you'll notice is that we have these five classes of antibodies arranged so that they fit our mnemonic, which is gained. And the IgG antibody is the very first one on this list. Notice that it is a monomer and it is the standard antibody. Uh It has a very, very long half life, which means that it's very stable and will last a long time within our bodies before it's broken down. Uh It is the most abundant class of antibody. Around 80% of all antibodies will be IgG. It has this amazing ability to cross the placenta between the mother and the baby, which is going to help provide the fetus uh immunity during pregnancy as well as even after birth. Because again, these IgG antibodies last such a long time that the mother's IgG antibodies in the baby will also help to protect the baby even after birth. And they're also important for activating the complement system which can lead to a variety of immune responses. Now, the IG A antibody notice it is a dimer and a lot of times we refer to this dimer as the secretory ig A antibody or SI G A antibody. Notice that its half life is medium and it's going to be important for protecting the mucus membranes. It's also found in many different types of body secretions including breast milk, which can help protect the infant's intestinal system. When a mother breastfeeds her baby, the next antibody that we have on here is the IgM antibody, which is the largest class of antibody. It is a pimer and its half life is medium and it is the very first antibody that is initially created by all plasma cells prior to antibody class switching, it helps to control infections in the bloodstream. That is its main role. And it also is the most effective class at activating the complement system. The the next class that we have here is the IgE antibody which again is a monomer and its half life is very, very short. Uh And so it is going to be found on both uh the surfaces of basophils as well as mass cells. And they're important for triggering the release of inflammatory mediators causing these basophils and mass cells to de granulate, releasing their Granules into their environment. Uh the inflammatory mediators can cause inflammation and the IgE antibodies also play a role in uh allergic reactions and we'll get to talk more about that later in our course, when we focus our attention on allergic reactions and hypersensitivities, uh they also play an important role in protecting against parasitic infections as well like parasitic worms, for example. Now, last but not least we have the IgD antibody, which is again a monomer and has a short half life, which means that it does not last very long within the body. Uh Now, the IgD antibodies are gonna be found on the surface of B cells or can be found on the surface of B cells. And they play an important role in helping to trigger B cell activation and differentiation into antibody secreting plasma cells. And so this here concludes our brief review of the five classes of antibodies and we'll be able to get some more practice applying these concepts as we move forward. So I'll see you all in our next video.
14
Problem
Problem
Each class of antibody is specifically defined by its
A
Amino acid sequence of the variable region of the light chain.
B
Amino acid sequence of the constant region of the heavy chain.
C
Ability to cross the placenta.
D
Disulfide bonds.
15
Problem
Problem
Match the following antibody classes with their description:
a) IgA. b) IgG. c) IgE. d) IgM. e) IgD.
___ First antibody produced during primary response.
___ Protects mucous membranes.
___ Most abundant antibody.
___ Found on the surface of B cells.
___ Triggers allergic reactions to allergens.
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3m
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