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
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This is because everyone’s immune system is slightly different, and some people tend to have stronger reactions than others to foreign substances.
—
Christopher P. Holstege, CNN Money, 17 Aug. 2025
Minor gastrointestinal discomfort is probably the most common symptom; however, pathogens that may cause only minor sickness in some people may cause serious conditions or death in others, especially in the very young, old, or those with weakened immune systems.
—Jalen Williams, Freep.com, 15 Aug. 2025
In the digestive system, beneficial bacteria help absorb nutrients, support digestion and the immune system, and prevent harmful bacteria from growing.2
Gastroesophageal reflux disease (GERD) and medications used to treat GERD can upset the balance of beneficial bacteria.
—Merve Ceylan, Health, 14 Aug. 2025
It is considered a serious condition and can be dangerous or life-threatening, especially to older adults, people with weak immune systems and pregnant people.
—Mary Walrath-Holdridge, USA Today, 12 Aug. 2025
See All Example Sentences for immune system
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Christopher P. Holstege, CNN Money, 17 Aug. 2025
Minor gastrointestinal discomfort is probably the most common symptom; however, pathogens that may cause only minor sickness in some people may cause serious conditions or death in others, especially in the very young, old, or those with weakened immune systems.
—Jalen Williams, Freep.com, 15 Aug. 2025
In the digestive system, beneficial bacteria help absorb nutrients, support digestion and the immune system, and prevent harmful bacteria from growing.2
Gastroesophageal reflux disease (GERD) and medications used to treat GERD can upset the balance of beneficial bacteria.
—Merve Ceylan, Health, 14 Aug. 2025
It is considered a serious condition and can be dangerous or life-threatening, especially to older adults, people with weak immune systems and pregnant people.
—Mary Walrath-Holdridge, USA Today, 12 Aug. 2025
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 21 Aug. 2025.
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