HELP! Problems with understanding class switching (immunology)

[planetmillion]

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I have a task about immunology, which has to be done tomorow, I tried to find informations both on the net, the books and youtube, but couldn't find anything until now. I'm stuck.

"Explain and illustrate with a drawing, the genetic mechanisms behind a normal immunoglobulin class switching and explain, what is the consequence of a class switching for the produced antibodies".

Anyone has some good information on that?

 

[CatFactorial]

Do you have to really explain much beyond CD40L?

 

[planetmillion]

I thought about explaining the picture from wikipedia, but I really doubt if that's enough?
http://en.wikipedia.org/wiki/File:Class_switch_recombination.png

 

[Vancomycin12]

Do you have to really explain much beyond CD40L?

x2! no CD40L = no class switching.

That wiki picture is pretty bad though. The basic immunology book (i forget author) explained it better in my opinion. It's actually a pretty simple concept with the right picture/caption. I went over this a few months ago and clearly forgot it already, so I don't have much to offer

 

[planetmillion]

well, I didn't find any better explanations. Do you know any site where it's explained pretty well, better than in Wikipedia?

I'm tired of googling and googling for hours and not finding the right info.

 

[CatFactorial]

CD40L (Helper T cell) - CD40R (Naive B cell) signaling induces the enzymatic removal of the heavy chain locus (heavy chain, not light chain, since we are just looking at Fc and not Fab) of IgM (naive B cells only express IgM and IgD), and the remaining DNA segment is spliced to the intended class.

Gene segments go IgM IgD IgG IgA IgE (or something like that). So after productive formation of BCR, if you want to make IgE for that particular BCR, IgM, D, G, and A segments will be excised out and the remaining DNA heavy chain segment will be spliced.

 

[Charles_Carmichael]

Yea, just explain that you need a particular cytokine environment and the CD40-CD40L interaction to induce class switching. The gene segments containing IgM, IgD, and any other C regions that you don't want to switch to will be excised out.

 

[planetmillion]

Thanx guys 🙂

 

[Ronin786]

Also mention that the CD40 stimulation of TH2 cells leads to release of IL4/IL5 and each one is responsible for certain class switching.