The lymphatic system and lymphoid organs get their name because they are concerned with the growth, development, and deployment of lymphocytes, white blood cells that are key to the immune system. Bone marrow Bone marrow is the soft tissue in the center of all the bones in the body. It produces both red and white blood cells. These two types of white blood cells are the immune system's front-line fighters. Bone marrow also houses the lymphocytes known as B cells until they reach maturity.
B cells fight disease by secreting antibodies into the body fluid.
These antibodies fight bacteria and viruses. The thymus is located near the top of the lungs and behind the breastbone. It is a key to immune response. Lymphocytes known as T cells get their name from the thymus because after bone marrow produces them, they are passed on to the thymus, which fosters their development. T cells both regulate immune response and attack infected or malignant body cells.