Question

Explain the difference between natural and artificial immunity, and give examples of each.

Answer 1

Natural immunity and passive immunity both form the part of adaptive immunity that is acquired by the body at later stages in life.

Natural immunity is the immunity that we obtain naturally from the environment. It can be categorized as:

Natual active immunity: Which is gained after we are exposed to any pathogen in the environmental surroundings, and our immune system response recognizes the pathogen and produces anibodies against it, e.g. natural immunity obtained for common cold which is caused by rhino viruses, ususally affectiing nasal passage.

Natural passive immunity: The immunity obtained from the placental transmission of antibodies IgG (immunoglobulin G) from mother to the foetus.

Artificial immunity is the immunity which is acquired by intentional exposure to the pathogens.

Artificial active immunity: Immunity obtained against a pathogen, by vaccination. (Injection of non-lethal dose of pathogen or its component to intiate a primary immune response). This immunity works on the basis of memory cells produced during the primary immune response which gets activated during a second encounter with the same pathogenic strain.

For example: Bacillus Calmette Guerin (BCG) maccine for Tuberculosis.

Artificial passive immunity. Immunity obtained by direct injection of antibodies that are not produced in an organism but produced in some other species. These antibodies are isolated and then administered to the organism , in case of recent outbreaks of pathogen in a locality or in case of serious wounds. This is comparitively short-term immunization.

For example: tetanus antiserum administered in case of deep wounds.