Humoral immunity is a crucial component of our adaptive immune system. It involves B cells, which are specialized white blood cells that produce antibodies. These antibodies circulate in body fluids such as blood and lymph, where they can recognize and neutralize foreign pathogens like bacteria and viruses.
B cell activation is a multi-step process. First, the naive B cell must recognize and bind to a specific antigen on the pathogen through its surface receptors. However, this alone is not sufficient. The B cell also requires help from helper T cells, which provide additional activation signals. Once both conditions are met, the B cell becomes fully activated and ready to differentiate.
Once activated, B cells differentiate into two distinct cell types. Most become plasma cells, which are antibody factories with extensive rough endoplasmic reticulum for protein synthesis. These cells rapidly produce large quantities of antibodies specific to the original antigen. A smaller portion becomes memory B cells, which remain dormant in the body for years, ready to mount a faster response if the same pathogen is encountered again.