Adaptive immunity refers to a type of acquired immunity a host develops after exposer to foreign substances or transfer of antibodies or lymphocytes from an immune donor.
1. Naturally acquired immunity
2. Artificially acquired immunity
(1) Naturally acquired immunity
- Naturally acquired active immunity
- Naturally acquired passive immunity
Naturally acquired active immunity occurs when an individual`s immune system contacts an antigen such as a pathogen that causes inflammation. the immune system responds by producing antibodies and activated lymphocytes that inactive or destroys the pathogen. the immunity produced can be either lifelong, as with measles or chickenpox, or last for only a few years, as with influenza.
Naturally acquired passive immunity involves the transfer of antibodies from one host to another. examples, some of a pregnant woman`s antibodies pass across the placenta to her fetus. if the woman is immune to diseases such as polio or diphtheria, this placental transfer also gives her fetus and newborn temporary immunity to these diseases. certain other antibodies can pass from a mother to her offspring when the child is fed breast milk. these maternal antibodies are essential for providing immunity to the newborn for the few weeks or months of life, as the child`s own immune system matures. naturally acquired passive immunity generally lasts only a short time.
(2) artificially acquired immunity
- artificially acquired active immunity
- artificially acquired passive immunity
artificially acquired active immunity results when an animal is vaccinated that is, intentionally exposed to foreign material and induced to form antibodies and activated lymphocytes. A vaccine may consist of the preparation of killed microorganisms genetically engineered organisms or their products or inactivated bacterial toxins` that bind to the whole bacterium, virus, toxin, and so forth to inactivate or help remove them from the host.
artificially acquired passive immunity results when antibodies or lymphocytes that have been produced by one host have been introduced into another this type of immunity is immediate, it is short-lived, lasting only a few weeks to a few months. an example of artificially acquired passive immunity would be botulinum antitoxin produced in horses and given to humans suffering from botulism food poisoning.
