KINE 2011 Lecture Notes - Lecture 18: Endoplasmic Reticulum, Complement System, B-Cell Receptor
11 Dec 2017
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Document Summary
Both b and t cells have constant regions and variable portions. The constant regions provide shape and support and are always there. The variable regions are at the tip, and they are what contact and bind the antigen. They are called variable regions because they are where we see variability between antigen receptors (10^11 di erent ones): the way we have such variability in the variable region is through gene segments. Gene segments are little pieces of sequence that randomly get stuck together to be the sequence of the variable region. The cutting and sticking is di erent every time, which is why we have such diversity: all of this is done during development, so we have this huge level of diversity before we ever encounter any antigens. When a b lymphocyte becomes activated, its shape changes dramatically. They become more elongated and get extensive growth in their endoplasmic reticulum.
