immune system

American  

noun

Anatomy.

immune systems plural

1. a diffuse, complex network of interacting cells, cell products, and cell-forming tissues that protects the body from pathogens and other foreign substances, destroys infected and malignant cells, and removes cellular debris: the system includes the thymus, spleen, lymph nodes and lymph tissue, stem cells, white blood cells, antibodies, and lymphokines.

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immune system Scientific  

1. The body system in humans and other animals that protects the organism by distinguishing foreign tissue and neutralizing potentially pathogenic organisms or substances. The immune system includes organs such as the skin and mucous membranes, which provide an external barrier to infection, cells involved in the immune response, such as lymphocytes, and cell products such as lymphokines.

2. See also autoimmune disease immune response

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immune system Cultural  

1. The system in the body that works to ward off infection and disease. Central to this system are the white blood cells. Some white blood cells produce antibodies in response to specific antigens that may invade the body; others function as scavengers to fight infection by destroying bacteria and removing dead cells.

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Other Word Forms

Noun Inflected Forms

• immune systems
  plural

Etymology

Origin of immune system

First recorded in 1960–65

Example Sentences

See Examples For:

immune system

Without it, malignant cells become much harder for the immune system to identify and kill.

From Science Daily ● Jul. 26, 2026

Most of the time, the immune system clears them quickly.

From The Wall Street Journal ● Jul. 26, 2026

Prostate cancer is notoriously difficult to treat with immunotherapy, a type of cancer treatment that helps the immune system identify and destroy tumors.

From Science Daily ● Jul. 26, 2026

Multiple sclerosis is caused by the immune system attacking the protective covering around nerve cells - known as myelin.

From BBC ● Jul. 22, 2026

Her immune system reacted badly to all the shots: they made her sick.

From "The Hot Zone" by Richard Preston