Immunity involves physiological mechanisms enabling the body to identify foreign materials and eliminate, and metabolize them without necessarily causing any harm to its own tissues, thus preventing any further infection/harm caused by the foreign substances. The first line of defence in the human body against pathogens is through barriers such as the skin, mucus layers, and saliva. This is known as innate immunity. The second line of defence is through phagocytes; this is again produced by innate immunity. The third line of defence is through adaptive immunity.
Active immunity and passive immunity are two types of acquired immunity. A prominent difference between active and passive immunity is that active immunity is developed due to the production of antibodies in one’s own body, while passive immunity is developed by antibodies that are produced outside and then introduced into the body. In this article, let us look at more differences between active and passive immunity.
Active Immunity and Passive Immunity- Differences
|Active Immunity||Passive Immunity|
|Active immunity is usually long-lasting, sometimes life-long. It is produced by the antibodies of the host in response to direct contact with an antigen||Passive immunity lasts only for a few weeks or months. It is produced by the introduction of antibodies from outside into the host|
|It produces an immunological memory||It does not produce immunological memory|
|When the antigens enter the body, antibodies and other specialised lymphocytes are produced||Antibodies are introduced from an external source. For instance, a mother introduces antibodies to a fetus through the placenta and to an infant via mother’s milk.|
|There are no side-effects||It may cause reactions|
|Immunity does not occur immediately||Immunity develops immediately|
- Active immunity is attained by exposure to a pathogen. This leads to the production of antibodies in the body. The antigens present on the surface of the pathogens act as markers that bind to the antibodies.
- Passive immunity is acquired when antibodies are introduced into the body from an external source (usually through vaccines). It provides a quick response to the infection.
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