As B-cells undergo affinity maturation, their BCR sequences change. Are they still considered to be part of the same clone?
I couldn't find a clear answer in response to this very similar question:
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There are different opinions on this, since it's about usage. You could make an argument that, if you're talking about a B-cell clone, it is the product of a specific VDJ recombination (a mature, but naive B-cell), and refers to B-cells that produce antibody to one antigen. However, the term was originally proposed in this context:
...the expendable cells of the body can be regarded as belonging to clones which have arisen as a result of somatic mutation or conceivably other inheritable changes. Each such clone will have some individual characteristic and in a special sense will be subject to an evolutionary process of selective survival within the internal environment of the body.
In this case, I'd argue that, when the BCR sequence changes in progeny from that original naive B-cell (as in affinity maturation), you end up with different clones.
You do have to be careful, though, because people use this term differently.