B cells (also known as B lymphocytes) are white blood cells that produce antibodies and function in the immune response. B cells are a type of lymphocyte, which are white blood cells that are part of the immune system. B cells are produced in the bone marrow and mature in the spleen and lymph nodes.

When B cells encounter an antigen, which is a foreign substance that the body recognizes as harmful, they produce antibodies that are specific to that antigen. Antibodies are proteins that bind to antigens and help to neutralize them. B cells also play a role in the immune response by helping to activate other immune cells, such as T cells.

There are two main types of B cells:

* Memory B cells: These cells are produced after a B cell has been exposed to an antigen. Memory B cells remain in the body and can quickly produce antibodies if the body is exposed to the same antigen again.

* Plasma B cells: These cells are produced when a B cell is activated by an antigen. Plasma B cells produce large amounts of antibodies and are responsible for the immediate immune response.