Different light chains combine with different heavy chains for an increase in
repertoire diversity. Antigens drive the selective process which involves
rearrangements similar to those found in the VH region of the heavy chains.
Additionally, it appears an additional advantage is the ability of alternate
light chain usage to rescue B cells which have an unproductive rearrangement of
a previous light chain.
darren at indy.bio.uts.edu.au wrote:
> A general question about light chain isotypes: in Ig molecules the HEAVY
> chain isotypes have well-defined seperate roles, eg differential binding to
> Fc Receptors, that can mean functional differences between the classes.
> However, I haven't read much about possible functional differences between
> kappa and lambda light chains. Also, it seems to me that K or L light chains
> associate haphazardly with the different Heavy chain isotypes; there is no
> real pattern of K in some situations and L in others. Can anyone tell me if
> there is a functional "raison d'etre" for the existence of these 2 different
> light chain isotypes. I am particularly interested in the evolutionary
> rationale as to why 2 types of light chain may be an evolutionarily
> progressive step over 1 light- chain type.
>> Thank you,
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