Immune response is the production of antibodies in response to antigens. An antigen is any foreign material or organism that is introduced into the body and causes the production of antibodies. Antigens are protein in nature.
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An antibody is a protein whose structure is complementary to the antigen. This means that a specific antibody deals with a specific antigen to make it harmless. When harmful organisms or proteins invade the body, lymphocytes produce complementary antibodies, while bone marrow and thymus gland produce more phagocytes and lymphocytes respectively.
Types of Immunity
There are two types of immunity; natural and artificial. Natural Immunity is also called innate immunity. It is inherited from parent to offspring. Artificial Immunity can be natural or induced. When attacked by diseases like chicken pox, measles and mumps, those who recover from these diseases develop resistance to any subsequent infections of the same diseases. This is natural acquired immunity.
Artificial Acquired Immunity:
When attenuated (weakened) or dead microorganisms are introduced into a healthy person. The lymphocytes synthesis the antibodies which are released into the lymph and eventually reach the blood. The antibodies destroy the invading organisms.
The body retains ‘memory’ of the structure of antigen. Rapid response is ensured in subsequent infections. Vaccines generally contain attenuated disease causing organisms.
Artificial Passive Acquired Immunity:
- Serum containing antibodies is obtained from another organism, and confers immunity for a short duration.
- Such immunity is said to be passive because the body is not activated to produce the antibodies.