Active and Passive immunity

09 May

Different Types of Immunity

Introduction to different types of immunity

Immunity is defined as the ability of the body to defense against pathogens. There are two  different types of immunity. They are innate immunity and acquired or adaptive immunity. Acquired immunity can be naturally acquired or artificially acquired immunity. Naturally acquired or artificially acquired immunity is further divided into two different types:active immunity and passive immunity.

Innate immunity

Innate immunity or inborn immunity is defined as the immunity inherited by the organism from parents and protects from birth throughout life. This type of immunity can be seen in humans against distemper a fatal disease of dogs.

Active immunity

Natural active immunity is acquired or occurs when individuals suffer from a natural infection of a pathogen and become immune to that pathogen upon recovery (e.g. chickenpox).

Artificial active immunity is acquired or occurs when individuals are actively vaccinated with an antigen that confers immunity. But some vaccines need to be given for every 3-5 years.

Passive immunity response is immediate but is not long lasting. Immunity is said to be passive when antibodies produced in another organism are injected into a person to induce protection against diseases. Passive immunity is acquired for rabies, tetanus and salmonella infection.

Passive acquired immunity is short lived because the antibodies die and are removed from the body as foreign protein and hence the immunity is said to be transient. They acquire naturally or artificially.

Naturally acquired passive immunity occurs when individuals receive antibodies from their mother by a natural process. For e.g. mothers milk or transfer of antibodies from mother to fetus.

Artificially acquired passive immunity occurs when individuals are injected with serum containing antibodies against a large number of pathogens.

Cellular immunity is produced by T-cell lymphocytes and humoral immunity is produced by B-cell lymphocytes.


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