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## Acquired Immunity Acquired immunity is the resistance that an individual develops in their lifetime. There are two types of acquired immunity. ### Active immunity * **Naturally acquired active immunity** is when an individual is exposed to the infection naturally and develops immunity due to ex...

## Acquired Immunity Acquired immunity is the resistance that an individual develops in their lifetime. There are two types of acquired immunity. ### Active immunity * **Naturally acquired active immunity** is when an individual is exposed to the infection naturally and develops immunity due to exposure. * **Artificially acquired active immunity** is when an individual is intentionally exposed to the infection via a vaccine. Vaccines are made by injecting a weakened or inactive form of the pathogen in order to trigger an immune response without causing disease. ### Passive immunity * **Naturally acquired passive immunity** is when antibodies cross the placenta from the mother to the fetus, providing the fetus with temporary immunity. * **Artificially acquired passive immunity** is when antibodies are injected into the recipient from an outside source. Antisera are made by injecting the pathogen into a host animal and extracting antibodies from the animal's blood, then injecting the patient with these antibodies. For example, after a snake bite, anti-venin, derived from the blood of a horse, is injected into the infected patient. ## Antibodies Antibodies are proteins that are found in the blood that act against germs or their secretions. * They are produced by specialized lymphocytes and are specific. * When a lymphocyte recognizes a foreign antigen, it triggers the body to produce antibodies that bind to the antigen, rendering the bacteria harmless. * They can make the bacteria clump together, making them easier to kill. ![Image depicting lymphocytes producing antibodies] This image shows a simplified representation of a lymphocyte recognizing a bacteria antigen and producing antibodies, which then bind to the bacteria and clump them together for easier destruction by phagocytes. The clumped bacteria can then be consumed and digested by a phagocytic white blood cell.