The term "active immunity" refers to the body's ability to create its own immunity against a specific antigen. In IPA phonetic transcription, the word /ˈæktɪv ɪˈmjuːnɪti/ would be spelled as "AK-tiv ih-MYOO-ni-tee". The stress falls on the first syllable of each word. The letter "c" in "active" is pronounced as a hard "k", while "immunity" has the "mm" sound pronounced distinctly, followed by an "i" sound. Overall, the spelling of "active immunity" accurately represents its pronunciation.
Active immunity refers to the protection that is acquired by an organism's own immune system in response to the presence of a pathogen or foreign substance. It is a type of immunity that develops when the body is exposed to antigens of specific pathogens, such as bacteria or viruses, triggering an immune response.
When the immune system encounters a pathogen, specialized cells called lymphocytes, including B cells and T cells, are mobilized. B cells produce antibodies that recognize and bind to specific antigens on the surface of the pathogen, while T cells directly attack infected cells. This coordinated immune response aims to eliminate the pathogen and prevent reinfection.
Active immunity is called "active" because it involves an active participation of the individual's immune system. This type of immunity can be acquired naturally through exposure to the pathogen itself, resulting in a primary immune response, or it can be induced through vaccination. Vaccination artificially stimulates the immune system by introducing a weakened or killed form of the pathogen or its antigens, stimulating an immune response and the production of memory cells.
The primary benefit of active immunity is the creation of memory cells, which allow the immune system to recognize and mount a rapid response to the same pathogen upon subsequent exposure. This leads to a much faster and more effective immune response, often preventing or mitigating the severity of the disease. Active immunity, whether acquired naturally or through vaccination, confers long-term protection against specific pathogens and plays a crucial role in defending the body against infections.
See acquired i.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.
The word "active" comes from the Latin word "activus", which means "doing, performing, or working". The term "immunity" comes from the Latin word "immunitas", which means "exemption from duty or public service". Therefore, the etymology of the word "active immunity" implies a state of exemption or protection from disease or pathogens that is achieved through the active working or performance of the body's immune system.