Harnessing the Power of the Immune System

The immune system is the body’s natural defense mechanism to prevent and combat disease. The immune system protects the body by specifically recognizing and destroying foreign invaders, such as viruses or bacteria. In addition, the immune system is capable of recognizing and eliminating abnormal cells from the body, such as infected cells or cancerous cells.

To accomplish this essential task, the immune system uses surveillance techniques to detect potentially life-threatening situations, and when encountered, deploys a variety of defense strategies to eradicate the problem.

The immune system can be described as possessing two complementary approaches to defend the body, labeled innate and adaptive immunity. Innate immunity, which is a rapidly acting “front-line” defense, includes dendritic cells, macrophages, natural killer cells and other components. Cells of the innate immune system are programmed to recognize structural components that may be present in disease-causing organisms. This triggers a prompt, but relatively non-specific immune response that defends against the invader and sends out alarm signals to the rest of the immune system.

Adaptive (or acquired) immunity, on the other hand, is designed to generate an immune response that is very specific for components (antigens) present in the foreign invader. This antigen-specific immune response, which involves B and T cells, evolves more slowly than innate immunity, and creates a powerful and sometimes very long-lasting defense that can be called upon again in the future.

Humoral and Cellular Immunity

Humoral and cellular immunity are two general types of immune responses that are used to defend the body.

• Humoral immunity refers to the production of antibodies by B cells, while
• Cellular immunity refers to the activities of other types of cells, including T cells.

B cells produce antibodies that prevent infection by attaching to the surface of invading pathogens and aiding in their disposal before they can infect cells. Once pathogens gain entry into cells, however, they are inaccessible to antibody and can survive inside cells for long periods of time. Therefore, humoral immunity is well-suited for the prevention of infection.

Next: Humoral Immunity (antibodies)