What is defined as the immunity gained after surviving a specific infection?

The concept of immunity gained after surviving a specific infection corresponds to the individual's immune system developing a response specifically tailored to that pathogen. This process is a fundamental aspect of how the immune system learns and remembers infections through a memory response.

Active immunity refers to the process whereby the immune system is exposed to an antigen, leading to the production of antibodies and memory cells that provide long-term protection. While protective immunity might describe the enhanced immunity that results from prior infections or vaccinations, it is not formally defined as the immunity gained from surviving an infection.

Passive immunity, on the other hand, involves receiving pre-formed antibodies from another source, such as through maternal antibodies or injections. This type of immunity does not involve the host's immune system producing a response and is typically temporary.

Adaptive immunity is a broader term that encompasses the specific immune responses that develop over time and can include both active and passive immunity. It reflects the ability of the immune system to adapt to new threats and retain memory for future encounters.

Therefore, the immunity gained specifically from surviving an infection accurately describes the concept of protective immunity, which encompasses the body's enhanced defense mechanism due to the previous encounter with a pathogenic threat.