Antibodies - Production, Structure, Domains, Types (IgG, IgD, IgA, IgE, IgM) | Immunology
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- Опубликовано: 28 июл 2024
- This video is part 2 of Acquired immunity - Antibodies
Content
Introduction: 0:00
Where do Antibodies come from? 0:06
Components of an Antibody: 5:31
Domains: 7:32
IgG: 8:37
IgM: 9:50
IgA: 11:53
IgD: 13:39
IgE: 14:22
Differences between antibodies: 15:17
Table to memorize: 15:56
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All information in my immunology videos are from:
- Book: Immunology, Eighth Edition by David Male, Jonathan Brostoff, David Roth and Ivan Roitt
- Additional research in PubMed
- University lecture materials
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Antibodies: Plasma proteins
Where they come from:
1. B-cell (with BCR - IgG/D) bind to antigen
2. Present it on MHC II
3. APC activates a naive Th cell through TCR (CD4 and CD3), B7/CD28 and IL-4 receptor
4. Naive T helper cell secretes IL2 (autocrine)
5. Becomes an active Th2
6. Th2 helps active B-cell through CD40L/CD40 and T cell receptor.
7. IL-4, IL-5, IL-8, IL-10, IL-2, IFN gamma released depending on what type of antibody is needed.
Components of an Antibody:
Has:
Light Chain
Heavy Chain
Variable Part
Constant
Becomes:
VL, Vh, CL, Ch1, Ch2, Ch3
CL-Ch1 Connected through disulfide bonds
two parts of antibody connected through a Hinge which give the antibody motility
divided into Fab (fragment antigen binding) and Fc (Fragment crystalizable region)
Antibody Domains:
- Variable region - Antigen binding sites
- Ch1 region - Determine Allotype
- Ch2 region - Binds Complement
- Ch3 region - Binds Cells
Variants of chains:
Light Chain:
- Lambda Chain
- Kappa Chain
Heavy Chain:
- Gamma Chain (IgG)
- My Chain (IgM)
- Alpha Chain (IgA)
- Delta Chain (IgD)
- Epsilon Chain (IgE)
Functions of IgG:
- Exists as: Monomeric (plus subtypes)
- Amount in Plasma: 75%
- IgG is only antibody that pass through placenta. so we get igG from mothers.
- Direct Opsonization
- Activate Complement System
- IgG responsible for the secondary response in humoral immune response because memory B-cells are made to produce IgG
Functions of IgM:
- Pentameric (with a J-Chain) and Monomeric on B-cells
- ''Youngest Class'' since a fetus can produce them.
- IgM reacts as the primary response, but no memory as they are produced by T-cell independent B cell proliferation
- Complement activation
Functions of IgA:
- Dimeric (J-chain), Monomeric and Trimeric
- Found at mucosal entry
- Alpha plasma cells secretes IgA. IgA binds to epithelium through poly IgA receptors and transported through cytoplasm through endocytosis and sent out through proteolytic cleavage
- Many microorganisms can cleave IgA
Functions of IgD:
- Under 1% in blood
- Localized on surface of B-cells
- Monomeric
Functions of IgE:
- Very low amount in blood
- Monomeric
- Mast Cell
- Responsible for Type 1 hypersensitivity. Made after sensitization.
- Increase amount of IgE during allergic diseases and parasite infections.
Differences between Immunoglobulins:
- Idiotypic differences: Differ in variable region
- Isotypic Differences: Antibodies differ in constant region
- Allotypic Differences: Difference between alleles of same constant gene
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Astonishing that a 18 minute video is as helpful as 4 hours with my lecturer in university
Informative, thanks for the video!
I loved this tutorial!
Great video thank very much 🙏🏻
Thank you 👍
This is so helpful
thanks very informative 👍👍
IgM is has ten binding sites so could it bind to ten antigens at a time ?????
Very interesting
Thank you for this tutorial!
glad it helped! :)
Very helpful and enjoyable ,thanks a lot.
Glad you found it helpful 😁👍
hello sir, my ige value is 1.00 mm/mL in every blood test I give and i have recurring infections, is it because my ige level is low thank you
Good to know bro
Think you
Hello! I've been searching for an answer to this question but have not had luck yet. Why don't IgM and IgE have the hinge section? I Understand that IgM and IgE have extra CH that functions like the hinge¿?
Good question. I'm actually not sure why it is so. Maybe it's due to their properties? Since IgM is a pentamer and IgE is on the surface of mast cells? If you find the reason why, please share! :)
Hey, it's very interesting. I just don't understand what you say. It's too complicated for me. I just need to ask you a question, why IgG/IgM rapid test different from one to other diseases? I mean, can we use thypoid rapid test for Covid-19, for example?
Hello! 😄 Are you asking how we can differentiate the antibodies? You probably already know, but antibodies are very specific to what they bind to, so if you wanna check presence of any antibody (like the typhoid rapid test you mentioned); you'd just need to add antigens which the antibodies you wanna check for binds to. There's many ways to look for antibodies but a lot of them work aorund Coombs Test (just google it if you want).
For the Covid-19 is no difference, easy to look for antibodies if you add specific Covid19 Ag. However nowadays you'd wanna check for presence of the virus itself since you're already immune against the virus if you have antibodies (which takes a few weeks to gain after infection). Immunocompromized people won't have the strength to fight the virus and make these antibodies and then the virus takes over. For that most effective is PCR to look for the virus itself.
Hope i understood your question correctly!
Hey great video may you make one lymphatic system and endocrine
Hi, thank you! Those are big topics though, I'll definitely write them down in my list of potential topics to cover :)
@@TaimTalksMed you welcome we have been excelling because of you.
Thank you for the video👍... Please,I have question about IgG, are they able to pass the placenta during all the pregnancy or just in a specific period of pregnancy!!???
Hi! It begins already at 1st trimester. Maternal IgG can be detected in cord blood as early as 8-10 weeks of gestation (but in low concentration). Maternal IgG concentrations in fetal blood increase from early in the second trimester through term, most antibodies being acquired during the third trimester :)
(There's a good article about this in NCBI called ''The Impact of IgG transplacental transfer on early life immunity'', you can just google it up if you like)
@@TaimTalksMed ooh OK ,yes..I'm really very thankful to you it's all clear now ..Thanks a lot Doctor😊
😊 🙏 thankz
Glad you found it helpful! 😊
Any problem igg in pregnency..?
crosses the placenta & confers passive immunity from the mother to the fetus
@@lubnaaboudaba6062 thank you
i m from india