Lymphocytes are made by the bone marrow and by other organs of the lymph system. Bone marrow is the spongy tissue inside the large bones in the body. Bone marrow cells are produced by immature immortal stem cells. White blood cells fight infection.
Platelets make the blood clot.
Lymphocytes are found in the lymph, a colorless, watery fluid in the lymph vessels. The lymph vessels are part of the lymph system, which is made up of thin tubes that branch, like blood vessels, into all parts of the body. Along this network of vessels are groups of small, bean-shaped organs called lymph nodes. Clusters of lymph nodes are found in the underarm, pelvis, neck, and abdomen. Lymphocytes fight infection by making antibodies, which attack germs and other harmful bacteria in the body.