B lymphocytes are cells that are initially produced in the yolk sac, then in the liver (during fetal life), and later in the bone marrow. They are responsible for ensuring the so-called humoral immunity, which stands out for the immune response made by the production of antibodies. These antibodies are capable of neutralizing or even destroying antigens. In addition to antibody production, B lymphocytes act as immune memory cells. These cells are able to react quickly to a new infection with the same antigen. As such, they ensure faster and more effective protection.
T lymphocytes originate from lymphoid progenitor cells found in the bone marrow. These cells leave the marrow towards the thymus. T helper lymphocytes guarantee the differentiation of B lymphocytes into plasma cells, and are therefore important for antibody production. Suppressor T lymphocytes terminate the humoral response, that is, antibody production. T lymphocytes are estimated to represent 65% to 75% of lymphocytes present in a person's blood.
NK cells (also a lymphocyte), or natural killer cells, are part of the innate immune system. These cells are able to distinguish infected or tumor cells and attack them without stimulation. Its immune response is nonspecific, unlike T and B lymphocytes, which produce responses by antigen action.