The immune response is how your body recognizes and defends itself against bacteria, viruses, and substances that appear foreign and harmful.

Innate immunity; Humoral immunity; Cellular immunity; Immunity; Inflammatory response; Acquired (adaptive) immunity

The immune system protects the body from potentially harmful substances by recognizing and responding to antigens. Antigens are molecules (usually proteins) on the surface of cells, viruses, fungi, or bacteria. Nonliving substances such as toxins, chemicals, drugs, and foreign particles (such as a splinter) can also be antigens. The immune system recognizes and destroys substances that contain these antigens.

Even your own body's cells have proteins that are antigens. These include a group of antigens called HLA antigens. Your immune system learns to see these antigens as normal and usually does not react against them.

INNATE IMMUNITY

Innate, or nonspecific, immunity is the defense system with which you were born. It protects you against all antigens. Innate immunity involves barriers that keep harmful materials from entering your body. These barriers form the first line of defense in the immune response. Examples of innate immunity include:

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Immune response

Phagocytosis

Phagocytosis

Vaccines

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Immune response Prevention

Review Date: 05/02/2010
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Stuart I. Henochowicz, MD, FACP, Associate Clinical Professor of Medicine, Division of Allergy, Immunology, and Rheumatology, Georgetown University Medical School. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org)