The Encyclopaedia Britannica defines lymphocytes as white blood cells that determine the specific response of the immune system to bacteria and toxins. They are present in the circulation and central lymphoid organs and tissues, where an immune response initially occurs.
The Encyclopaedia Britannica states that lymphocytes are primarily categorized into B lymphocytes and T lymphocytes, also called B cells and T cells. Both types of lymphocytes come from stem cells in the bone marrow. Some travel to the thymus and mature into T cells, while others stay in the bone marrow and develop into B cells.
Lymphocytes generally last for a short time, with an average life span ranging from a week to a few months, although some cells live for years and form a group of long-lived T and B cells, according to the Encyclopaedia Britannica. These lymphocytes are responsible for immunological memory, a faster, vigorous response to a subsequent encounter with the same antigen, such as a microorganism or foreign substance. They remove these antigens from the body by binding the antigens through the receptor molecules on their surfaces.
Lymphocytes then multiply into clones of identical cells, which produce antibodies that neutralize or destroy the targeted antigen, says the Encyclopaedia Britannica. The body continues to produce antibodies for several days or months until the antigen is destroyed.