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

Proposition 38 would authorize the state to issue $8.4 billion in bonds to fund immunology and immunotherapy research to uncover treatments that help the immune system fight diseases such as cancer more effectively.

From Los Angeles Times ● Oct. 1, 2026

The infection also weakens the immune system, leaving children vulnerable to other infections.

From BBC ● Sep. 30, 2026

Injecting antibodies can help provide temporary protection against a virus or, if already infected, help the immune system fight it off.

From The Wall Street Journal ● Sep. 28, 2026

During haze, orangutans show signs of fat breakdown despite eating more and resting more, suggesting elevated energy demands likely from an immune system forced to work harder, it said.

From Barron's ● Sep. 26, 2026

A “smooth” strain possessed a slippery, sugary coat on the cell surface and could escape the immune system with newtlike deftness.

From "The Gene" by Siddhartha Mukherjee