One of the fascinating aspects of the immune system is that it has a memory and the capacity to learn. In order to have room for all the cells needed to match millions of possible enemies, the immune system stores just a few of each kind. When an antigen appears, those few matching cells multiply into a full-scale army. Within the humoral system, the prime responsibility for the immune response lies with the B cells. Each B cell is specific to the production of one type of antibody.
Every plasma cell is essentially a factory for producing antibodies.
Each of the plasma cells from a given B cell manufactures millions of identical antibody molecules and pours them into the blood stream. An antibody matches an antigen much as a key matches a lock. But whenever antibody and antigen interlock, the antibody marks the antigen for destruction. The amount or concentration of a particular antibody that is in solution can be measured in a laboratory. Here is something more to think about.