Given the enormous heterogeneity of antigen receptors expressed on the populations of naive B and T lymphocytes, the adaptive im
mune response relies on a process whereby the rare lymphocyte that binds to the antigen is first induced to proliferate, before it can perform its effector function. For B cells, there is a clever mechanism that ensures that the specificity of the antibody secreted by the plasma cell will recognize the same pathogen that initially stimulated the B cell antigen receptor and induced B cell proliferation. This mechanism is:
The naïve B cell expresses a membrane-bound form of the antibody as a receptor and secretes that same antibody when it differentiates into a plasma cell.
Explanation:
Naive B cell is a type of B cell that has still not been exposed to the antigen. The B cell receptors (BCRs) are transmembrane proteins composed of 1-a surface immunoglobulin molecule capable of recognizing the antigen, and 2-two transmembrane subunits that transduce the signal. When a B cell binds to antigen with its BCR, the B cell will proliferate and differentiate into a plasma cell. This plasma cell then releases antibodies, which are soluble forms of the BCR where the transmembrane domain that anchors the antibody protein to the membrane of the B cell is eliminated.
