Lymph nodes are major sites of B lymphocytes that plays a central role in cell-mediated immunity.
Adaptive immune system . Like the innate system , the adaptive system includes both humoral immunity components and cell-mediated immunity components . A lymph node or lymph gland , is an ovoid or kidney-shaped organ of the lymphatic system , and of the adaptive immune system , that is widely present throughout the body . Lymph nodes are major sites of B and T lymphocytes , and other white blood cells .