What type of immunity is developed through direct exposure to an antigen?

The correct answer is active immunity. This type of immunity develops when the body is exposed to an antigen, such as through an infection or vaccination, which triggers the immune system to respond. In the process, the immune system produces antibodies and memory cells specific to that antigen, allowing for a stronger and faster response if the same pathogen is encountered again in the future.

Active immunity is characterized by its long-lasting nature, as the immune system retains a memory of the exposure, leading to a more effective defense against future infections. This is in contrast to passive immunity, where pre-formed antibodies are transferred from one individual to another (e.g., maternal antibodies to a fetus), resulting in immediate but short-lived protection.

While natural immunity can occur through exposure to pathogens in everyday life, it is more general and does not specifically indicate the process of the body actively producing its own antibodies. Artificial immunity, on the other hand, typically refers to immunity gained through vaccinations, which is a specific method of inducing active immunity. Thus, while both natural and artificial types can contribute to an overall immune response, active immunity is specifically characterized by the body’s direct exposure to an antigen and the subsequent immune response it generates.