The Biology Project: Immunology

Introduction to Immunology Tutorial

Innate vs. Adaptive Immunity

The immune system is typically divided into two categories--innate and adaptive--although these distinctions are not mutually exclusive.

Innate immunity
Innate immunity refers to nonspecific defense mechanisms that come into play immediately or within hours of an antigen's appearance in the body. These mechanisms include physical barriers such as skin, chemicals in the blood, and immune system cells that attack foreign cells in the body. The innate immune response is activated by chemical properties of the antigen.
Adaptive immunity
Adaptive immunity refers to antigen-specific immune response. The adaptive immune response is more complex than the innate. The antigen first must be processed and recognized. Once an antigen has been recognized, the adaptive immune system creates an army of immune cells specifically designed to attack that antigen. Adaptive immunity also includes a "memory" that makes future responses against a specific antigen more efficient.

The Biology Project
The University of Arizona
May 24, 2000
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