immunology gene rearrangement q.

[HiddenTruth]

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Ok, so let me get this straight. I had always thought that both the kappa (K)and lambda (Y) are chains and simply not constant domains, i.e, they both have different variable regions. Is this not correct? According to kaplan immuno, they say that the K and Y chains are constant domains and determine the only 2 isotype possibilities of light chains. So, in determining IDIOTYPIC possibilities wouldn't you add the gene rearr. possibilities of both K and Y and then multiply by number of gene rearr. of H chains? (E.g ([K]VxJ) + [Y]VxJ) x [H]VxDxJ). My whole point here is whether the K and Y chains are considered as constant domains (in which case u wouldn't add them to determine idiotypes), or they are separate chains, eaching having a different variable and constant domain (in which case you would add them)? Sorry, if this is confusing--

 

[ucbdancn00]

Ok, so let me get this straight. I had always thought that both the kappa (K)and lambda (Y) are chains and simply not constant domains, i.e, they both have different variable regions. Is this not correct? According to kaplan immuno, they say that the K and Y chains are constant domains and determine the only 2 isotype possibilities of light chains. So, in determining IDIOTYPIC possibilities wouldn't you add the gene rearr. possibilities of both K and Y and then multiply by number of gene rearr. of H chains? (E.g ([K]VxJ) + [Y]VxJ) x [H]VxDxJ). My whole point here is whether the K and Y chains are considered as constant domains (in which case u wouldn't add them to determine idiotypes), or they are separate chains, eaching having a different variable and constant domain (in which case you would add them)? Sorry, if this is confusing--

my understanding is that if it's a the kappa designation and lambda designation are only with reference to the constant region (much like the IgG vs IgA). it is the constant region of the heavy chain that determines the effector function of that particular isotype of Ab. However, as the kappa and lambda chains each have a variable region (that contributes to the hypervariably region responsible for the idiotype) it would probably necessary to include the light chains. of course....it's probably important to account in your calculation that kappa chains make up 2/3 of light chains versus lamda making up only 1/3. (it's not a 1:1 ratio).

hope this helps and sounds about right....hope you and I kick some ass man..

ucb

 

[HiddenTruth]

my understanding is that if it's a the kappa designation and lambda designation are only with reference to the constant region (much like the IgG vs IgA). it is the constant region of the heavy chain that determines the effector function of that particular isotype of Ab. However, as the kappa and lambda chains each have a variable region (that contributes to the hypervariably region responsible for the idiotype) it would probably necessary to include the light chains. of course....it's probably important to account in your calculation that kappa chains make up 2/3 of light chains versus lamda making up only 1/3. (it's not a 1:1 ratio).

hope this helps and sounds about right....hope you and I kick some ass man..

ucb

dang, i didn't know about the differences in ratio. In fact it's not even listed in the immuno text we used for class--anyways, i doubt we need to know this for the step anyways. But, getting back to my orig question. While, kappa and lamda may be considered constant region determinants, if they are included in determining the idiotype, then their variable regions are different (unlike H chains), thus, making them different chains all together. While, in the H chains, the variability regions are the same, independentt of their constant region (that's because of isotype switching). Ok,I don't even know what I am asking anymore--but I got my answer--you would count both chains! Thanks.

Yea, i hope we kick some ass too--way too much crap to know, though.

 

[ucbdancn00]

dang, i didn't know about the differences in ratio. In fact it's not even listed in the immuno text we used for class--anyways, i doubt we need to know this for the step anyways. But, getting back to my orig question. While, kappa and lamda may be considered constant region determinants, if they are included in determining the idiotype, then their variable regions are different (unlike H chains), thus, making them different chains all together. While, in the H chains, the variability regions are the same, independentt of their constant region (that's because of isotype switching). Ok,I don't even know what I am asking anymore--but I got my answer--you would count both chains! Thanks.

Yea, i hope we kick some ass too--way too much crap to know, though.

actually you bring up a good point; for a particular idiotype...you would have to assume that 2/3 of the light chains are k and 1/3 are lambda (since they are within the same event....you would add this up.....and then multiply via H chain..

however...just remember that allelic exclusion ensures that the Ab produced has a hypervariable region specific for one type of epitope...

alright...hope this helps

ucb

 

[HiddenTruth]

actually you bring up a good point; for a particular idiotype...you would have to assume that 2/3 of the light chains are k and 1/3 are lambda (since they are within the same event....you would add this up.....and then multiply via H chain..

however...just remember that allelic exclusion ensures that the Ab produced has a hypervariable region specific for one type of epitope...

alright...hope this helps

ucb

cool, thanks!

 

[Bounty]

whoa...do we need to be able to do calculations like that? yikes!

 

[ucbdancn00]

whoa...do we need to be able to do calculations like that? yikes!

probably not...hidden was just raising an important point...

i'd be scared ****less otherwise; hell i'm scared ****less now..

ucb