Thông tin khoa học

B cell responses occur in several distinct phases. The process begins when a naïve B cell clone is activated. This activation happens when its specific antigen binds to the B cell receptor (BCR) on the cell's surface.

Once activated, the B cell receives additional stimuli, often through cytokines produced by T helper (TH) cells or other immune cells. These stimuli induce the B cell to undergo clonal expansion, where it proliferates and increases in number.

Following proliferation, the B cell can differentiate in one of several ways. It may directly differentiate into a plasma cell that secretes IgM-type antibodies.

Alternatively, the B cell may first undergo isotype switching in response to specific signals. After switching, it differentiates into a plasma cell that secretes different classes of antibodies, such as IgG, IgA, or IgE.

In another possible pathway, the B cell may first allow affinity maturation to occur. This process improves the binding affinity of the antibodies. The B cell then differentiates into either a plasma cell that secretes these higher-affinity antibodies or into a long-lived memory B cell, which can respond more rapidly upon future exposure to the same antigen.