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Innate Immunity

by Peter J. Delves, PhD

Innate (natural) immunity is so named because it is present at birth and does not have to be learned through exposure to an invader. It thus provides an immediate response to foreign invaders. However, its components treat all foreign invaders in much the same way. They recognize only a limited number of identifying substances (antigens) on foreign invaders. However, these antigens are present on many different invaders. Innate immunity, unlike acquired immunity, has no memory of the encounters, does not remember specific foreign antigens, and does not provide any ongoing protection against future infection.

The white blood cells involved in innate immunity are

  • Monocytes (which develop into macrophages)

  • Neutrophils

  • Eosinophils

  • Basophils

  • Natural killer cells

Each type has a different function.

Other participants in innate immunity are

  • The complement system

  • Cytokines