immunity: The Immune Response

The principal parts of the immune system are the bone marrow, thymus, lymphatic system, tonsils, and spleen. The lymph nodes, tonsils, and spleen act to trap and destroy antigens from the lymph, air, and blood, respectively. Antigens are molecules that the body reacts to by producing antibodies, highly specific proteins also known as immunoglobulins. Antigens include bacteria and their toxins, viruses, malignant cells, foreign tissues, and the like. Their destruction is accomplished by white blood cells (lymphocytes and the granulocytes and monocytes mentioned above), which are produced and constantly replenished by the stem cells of the bone marrow. The two types of lymphocytes are called B lymphocytes (B cells) and T lymphocytes (T cells). B cells are responsible for production of antibodies in what is called “humoral” immunity after the ancient medical concept of the body humors.

Sections in this article:

• Introduction
• Undesirable Immune Responses and Conditions
• Active and Passive Immunity
• T Lymphocytes
• Antibodies
• B Lymphocytes
• The Immune Response
• Nonsusceptibility
• Interferons
• Inflammatory Response
• Nonspecific Defenses
• Bibliography

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