Immune System
The body's coordinated network of cells, tissues, and organs that detects and defends against pathogens, toxins, and abnormal cells. It includes innate barriers and adaptive responses such as antibodies and T cells that build lasting immunity.
What is the immune system?
The immune system is the body's coordinated network of cells, tissues, and organs that detects and defends against threats such as bacteria, viruses, toxins, and abnormal cells. It distinguishes the body's own healthy tissue from foreign or dangerous material and mounts responses to neutralize what it identifies as harmful.
It operates through two broad arms. Innate immunity provides immediate, general defenses such as physical barriers and rapid-response cells, while adaptive immunity develops targeted responses, including antibodies and T cells, that can recognize specific pathogens and build lasting memory.
Why is the immune system important?
Because the immune system is the foundation of the body's defense against infection and disease, understanding it is essential to preventing and treating illness. Its memory function is what allows vaccines to confer durable protection.
Immune function also underlies much of modern medicine, from managing transplant rejection and autoimmune disease to harnessing immune responses against cancer. A patient's immune status can influence surgical risk, healing, and susceptibility to postoperative infection.
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