immune system
noun
: the bodily system that protects the body from foreign substances, cells, and tissues by producing the immune response and that includes especially the thymus, spleen, lymph nodes, special deposits of lymphoid tissue (as in the gastrointestinal tract and bone marrow), macrophages, lymphocytes including the B cells and T cells, and antibodies
Examples of immune system in a Sentence
Recent Examples on the Web
In clinical care, physicians aim to reduce immune system overactivity, control inflammation and prevent long-term damage, which is often done through medication.
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Daryl Austin, USA Today, 5 Jan. 2026
Flu is particularly dangerous for people 65 and older, pregnant women, young children, and people of any age who have chronic health problems, including asthma, diabetes, heart disease, and weak immune systems.
—Kaley Fedko, CBS News, 5 Jan. 2026
The immune system still identifies it, but less effectively – which increases the odds of the virus taking hold and advancing.
—New Atlas, 5 Jan. 2026
Despite boosting the immune system, vitamin C may not prevent you from getting sick.
—Sarah Bence, Verywell Health, 5 Jan. 2026
See All Example Sentences for immune system
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Daryl Austin, USA Today, 5 Jan. 2026
Flu is particularly dangerous for people 65 and older, pregnant women, young children, and people of any age who have chronic health problems, including asthma, diabetes, heart disease, and weak immune systems.
—Kaley Fedko, CBS News, 5 Jan. 2026
The immune system still identifies it, but less effectively – which increases the odds of the virus taking hold and advancing.
—New Atlas, 5 Jan. 2026
Despite boosting the immune system, vitamin C may not prevent you from getting sick.
—Sarah Bence, Verywell Health, 5 Jan. 2026
See All Example Sentences for immune system
Cite this Entry
“Immune system.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/immune%20system. Accessed 6 Jan. 2026.
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