The different types of immunity are active immunity, passive immunity, natural immunity and artificial immunity, according to Austin Peay State University. Active immunity refers to an immune response that results from exposure to a particular antigen.
When the body is exposed to an antigen and responds by activating the immune system, the resulting immune response is called active immunity, APSU explains. The immune system generates clones of antigen-specific B and T lymphocytes. In contrast, passive immunity develops when a person receives immune molecules or immune cells from another individual who was previously exposed to a specific antigen. The response is not the product of the activation of the body's own immune system. Natural immunity is an immune response that occurs due to exposure to an antigen in an external environment without the interference of medical therapy or practice. Artificial immunity involves medical therapy or practice intervention that results in exposure to a particular antigen, causing the development of an immune response.
APSU states that natural and artificial immunity are either active or passive. Natural active immunity develops due to exposure to foreign toxins, allergens, drugs or venoms, whereas artificial active immunity develops from exposure to a vaccine that provides protection against disease organisms.