Immunoglobulin Isotypes | Antibody Classes

An antibody (Ab), also known as an immunoglobulin (Ig),is a large, Y-shaped protein produced mainly by plasma cells that is used by the immune system to neutralize pathogens such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of the pathogen, called an antigen, via the fragment antigen-binding (Fab) variable region. Each tip of the "Y" of an antibody contains a paratope (analogous to a lock) that is specific for one particular epitope (analogous to a key) on an antigen, allowing these two structures to bind together with precision. Using this binding mechanism, an antibody can tag a microbe or an infected cell for attack by other parts of the immune system, or can neutralize its target directly (for example, by inhibiting a part of a microbe that is essential for its invasion and survival). Depending on the antigen, the binding may impede the biological process causing the disease or may activate macrophages to destroy the foreign substance. The ability of an antibody to communicate with the other components of the immune system is mediated via its Fc region (located at the base of the "Y"), which contains a conserved glycosylation site involved in these interactions. The production of antibodies is the main function of the humoral immune system.
Antibodies are secreted by B cells of the adaptive immune system, mostly by differentiated B cells called plasma cells. Antibodies can occur in two physical forms, a soluble form that is secreted from the cell to be free in the blood plasma, and a membrane-bound form that is attached to the surface of a B cell and is referred to as the B-cell receptor (BCR). The BCR is found only on the surface of B cells and facilitates the activation of these cells and their subsequent differentiation into either antibody factories called plasma cells or memory B cells that will survive in the body and remember that same antigen so the B cells can respond faster upon future exposure In most cases, interaction of the B cell with a T helper cell is necessary to produce full activation of the B cell and, therefore, antibody generation following antigen binding.Soluble antibodies are released into the blood and tissue fluids, as well as many secretions to continue to survey for invading microorganisms.
Antibodies can come in different varieties known as isotypes or classes. In placental mammals there are five antibody isotypes known as IgA, IgD, IgE, IgG, and IgM. They are each named with an "Ig" prefix that stands for immunoglobulin (a name sometimes used interchangeably with antibody) and differ in their biological properties, functional locations and ability to deal with different antigens, as depicted in the table.[33] The different suffixes of the antibody isotypes denote the different types of heavy chains the antibody contains, with each heavy chain class named alphabetically: α (alpha), γ (gamma), δ (delta), ε (epsilon), and μ (mu). This gives rise to IgA, IgG, IgD, IgE, and IgM, respectively.

[@sarahasif9567]

Love your videos! Best explanation I've heard so far 👍👍

[@hussainbiology]

thanks for appreciation..Glad to know that it helps ✌️

[@hamihamro]

Love your video and the way you say "occurs"

[@MGcreativedrawing]

Good explanation

[@hussainbiology]

Keep watching

[@amalbreikat4359]

That’s very helpful, thank you 😊

[@vyshuvyshu7126]

It's a very nice explanation 👍thank u....

[@artzylens8777]

valuable content 👍👍👍

[@Wildly_om]

Mind Blowing

[@hussainbiology]

thanks for appreciation

[@cjlevin4622]

This explanation is fire

[@hussainbiology]

thanks for appreciation

[@sanjaykumar-ew6mb]

Nice presentation

[@santosh__zond9101]

Beautiful explanation

[@hussainbiology]

thanks for appreciation

[@michaeleisenberg7867]

Shabir, Fascinating! Easy to understand.Thank you and keep up the good work! No evolution comments today 😘.

[@hussainbiology]

thanks Doc for appreciation......
Well i was thinking of making videos on Evolution but none of videos will remain specific since Evolution always tends to branch here or there and remains suspended at anytime....

[@michaeleisenberg7867]

@@hussainbiology Shabir, You sort of stuck the secretory component of IgA & the J chain in there so I had to Google them. The secretory component of IgA is another of the many helper or add on proteins that are required for the finished product. The construction of IgA in the plasma cell, delivery from the local plasma cell to the epithelial cell, and finally the secretion into the lumen or mucosal barrier is a highly complex process. It was very clever of evolution. The local plasma cell produces the IgA, it then binds to an Ig membrane receptor on the epithelial cell, taken up by endocytosis, then passes thru the epithelial cell still attached to the Ig membrane receptor, to finally be secreted into the lumen. Proteolysis of the Ig membrane receptor occurs on the way out, and only the protective "secretory" portion of the Ig membrane receptor remains attached to the IgA. Where did all these things come from? Your evolution videos will need a time machine 😉!
en.wikipedia.org/wiki/Secretory_component

[@shalinikumari8950]

Nice vedio.
Appreciation points i must mention -
●to the point
●short explanation
●useful information
😊keep it up

[@hussainbiology]

thanks for appreciation

[@biology_mcqs3037]

Informative video brother..... But u had missed a bit of information....
IgG2 do not cross the placenta.
In most cases heavy chain have 3 domains but in case of IgM and IgE they are having four constant domains.
IgG4 do not activate the classical pathway.
IgG is having highest half-life 23 days

[@hussainbiology]

✓IgM and IgE having 4 Constant Domains in heavy chain is mentioned in the video.
✓ igG Crosses Placenta but i have not gone down to subtypes which one's don't.
In the same way i have mentioned the basic functions without poking the subtype functions

[@biology_mcqs3037]

@@hussainbiology u had mentioned subtypes that's why I mentioned some of these exceptions

[@Isterbollen]

Thank yooooouuuuu

[@saisudheerreddy]

Thanks a lot😊😊

[@hussainbiology]

thanks for appreciation

[@raziyamomin5393]

sir plz ...make a video on microbioogy classes

[@hussainbiology]

InshaAllah soon

[@pallavi12mj]

Very nice explanation sir, could you upload video of" Antigenic Diversity- Gene Rearrangement" also, thank you :)

[@qadeerunnisa4673]

th-cam.com/video/mcHta6jju18/w-d-xo.html

[@godfather4047]

May I please know the reason for high IgE level?

[@s.r0700]

Sir thanks a lot for this
Sir can u upload a new video of pcr technique pls
Our university exams are coming

[@hussainbiology]

thanks for appreciation

[@nishatfatima2091]

Sukriya sir...

[@hussainbiology]

thanks for appreciation

[@qadeerunnisa4673]

th-cam.com/video/mcHta6jju18/w-d-xo.html

[@medicalbiochemistry_]

Good

[@hussainbiology]

✌️

[@amishasoni4002]

👌👍👍👍

[@zj6785]

Where is the previous video?????? Plzzzzz help i really need it 😫😢😩😭

[@hussainbiology]

Here it is....
th-cam.com/video/uvlah0Qensg/w-d-xo.html

[@hussainbiology]

✌️😊.... Sorry i forget to put link in description

[@saimarashid3518]

🌺🌺

[@hussainbiology]

✌️✌️

[@measententia2154]

What is ADCC?

[@hussainbiology]

th-cam.com/video/rNwtGK1p2zs/w-d-xo.html

[@hussainbiology]

Antibody Dependent Cell-Mediated Cytotoxicity.... The Upper link is my video on it but it us quite old and less informative....
✌️

[@measententia2154]

@@hussainbiology ok..thank you❤️👍

[@hussainbiology]

@@measententia2154 ❤️❤️ Wlcm wlcm✌️

[@vishipsherrah]

0:30 IgG is sus

[@botsacharishma7398]

Explanation good but plz tell slowly

[@zainulabidinkhan4186]

9i