Class MHC I & II and the like. (1 Viewer)

[.ben]

Do we have to know about these things? they seem very complicated.

 

[Survivor39]

OMG.. You don't need to know them... They are probably too difficult to understand for year 12 Biology. I didn't even know what they do in Year 12 Biology.

But in case you're interested and in very simple terms, MHC Class I and II are important surface molecules that help to "present" foreign peptides to your T cells. So once your T cells know foreign molecules are present, such as a bacterium component or a viral component, the T cell then go after these foreign peptide and kill them. Therefore, these are also important molecules in transplantation because organs that are not yours (except for identifical twins) are recognised by the immune system as "foriegn" and rejection occurs. This is why they are called "Major Histocompatibility Complex". Note histo = tissue, so tissue compatibility.

Don't worry too much about them.

 

[.ben]

Wow sounds complicated how do you know all this lol

 

[Survivor39]

Have you ever looked at my Signature?

" B Medical Science at University of New South Wales (Third Year)
Subjects: MICR3021 (Microbial Genetics), MICR3041 (Immunology 1), MICR3071 (Environmental Microbiology), MICR3081 (Bacteria and Disease) "

 

[.ben]

sorry my thing doesn't display signatres or avatars.

btw do we have to know about IgA, IgM etc?

 

[Survivor39]

No you don't need to know about IgA or IgM (or IgD, IgG, IgE). You just need to know they are different classes of antibodies, secreted by activated B cells or plasma cells. Some of them maybe neutralising antibodies, which bind and neutralise antigens, such as toxins. Some antibodies are opsonising antibodies, which promote phagocytosis.

 

[.ben]

mmhmm. thank you very much!

 

[+Po1ntDeXt3r+]

Survivor39: did u hear about a mhc-III???

.ben: yep it gets easier with time n lectures..

 

[Survivor39]

No I haven't heard of MHC Class III. Is it a recent discovery?

 

[lil_georgie_gal]

Yea our bio teacher showed us an animation which went through all this MHC I and II but said we didnt need to know just know that there present and where.

Same with the immunoglobins like IgA know theres main ones and maybe just one example of what one does/or is present in

 

[+Po1ntDeXt3r+]

No I haven't heard of MHC Class III. Is it a recent discovery?

would i lie?

umm it doesnt code for an HLA tho so not realli related to CMI .. but it produces cytokines (e.g. TNF) and complement factors and other factors relating to class 1 and 2

i think its old but its important for new insight to immuno-disease.. read a new article on graves about it... i was hopeing for some insight from u

 

[Cade]

Hmm well from what my lecturers taught me, what i can understand is Class MHC I is present on almost all nucleated cells in our body. Thats how they help distinguish between our own body cells and foreign cells. Class MHC I is involved in the recognition of antigens by T-cells then.Does that mean that MHC I only binds to infected body cells that display antigens?

As for MHC II, they're only present on few cells; macrophages and B-cells. Well i kinda think that MHC II only binds on the surface of the macrophage and B-cells cuz when macrophage engulfs an antigen, they then have small fragments of antigen on its surface. MHC II recognizes this antigen and binds to it, alerting helper T-cells.

 

[+Po1ntDeXt3r+]

Hmm well from what my lecturers taught me, what i can understand is Class MHC I is present on almost all nucleated cells in our body. Thats how they help distinguish between our own body cells and foreign cells. Class MHC I is involved in the recognition of antigens by T-cells then.Does that mean that MHC I only binds to infected body cells that display antigens?

your statements
Class MHC I is present on almost all nucleated cells in our body- ???? [what other exceptions?... cos only think i can think of are possibly pro-erythoblasts?] Most books notably Abbas AK - "Basic immunology" state that it was all nucleated..tho someone on wiki said the same as u... tho its source was not referenced :S id be interested to know wat exceptions of nucleated cells ure lecturers were talkin about..

Thats how they help distinguish between our own body cells and foreign cells. -True
Class MHC I is involved in the recognition of antigens by T-cells then- True

Does that mean that MHC I only binds to infected body cells that display antigens?...

not from my understanidng..... recall MHC I is on almost all cells... it allows all cells to kinda show wat is inside itself (i.e it displays the antigen).. by sampling proteins that it is producing and presenting them... given your wording it does not bind externally.. your body's cells will present a whole heap of self proteins that due to anergy wil not react...

e.g in a viral infection of a cell... this is intracellular.. when the viruses use the cell's ER and golgi apparatus to produce proteins... the cell's MHC-1 samples a bit of the synthesized protein and displays it on surface (grossly simplified) ... which since the protein is foreign.. well lead to an immune reaction via CD8+ T cells.