The Basics

Immune system: the body’s biological shield against a continuous onslaught of pathogens

The immune system is essential to everyone’s health and survival, and it has become a critical component of medical discovery, healthcare, and disease management.

Immunology: study of the structure and functions of the immune system, which contains the organs, tissues, cells, and cell products that protect our body from disease

Immune defense: the coordinated reaction of the many parts of the immune system to fight disease-causing agents, such as viruses and bacteria, and to keep damaged cells from becoming malignant

Inflammation: the gathering of immune system cells and molecules at a site of infection, a protective response that causes swelling, redness, and pain

Prolonged or mis-regulated inflammation harms body tissues. Heart disease, Alzheimer’s, ulcers, and frailty in old age appear to be linked to chronic inflammation triggered by the immune response.


Adhesion molecules: sticky cell surface molecules that facilitate intercellular binding and communication

Antigen: a foreign substance recognized by the immune system

Autoimmunity: when the immune system attacks healthy tissue, or “self”

B cells: immune cells that mature in the bone marrow

Complement system: proteins in the bloodstream that provide first-response immunity

Immune cell migration: how and why an immune cell travels the bloodstream and lymphatic system and then enters infected or healthy tissue

Primary immune deficiency: when the immune system becomes compromised and leaves the body open to infection and disease

T cells: immune cells that mature in the thymus

Transgenic mice: genetically altered mice that serve as disease models for experimentation