Which type of immunity develops following exposure to an antigen?

Specific immunity, also known as adaptive immunity, develops following exposure to an antigen and involves an immune response that is tailored to a specific pathogen. When the body encounters an antigen, the immune system learns to recognize it, leading to the activation of lymphocytes (T cells and B cells) that produce a targeted response. This type of immunity has memory capabilities, allowing for a faster and stronger response to subsequent exposures to the same antigen.

Passive immunity involves the transfer of antibodies from one individual to another, such as from mother to infant through breast milk or through antibody injections. This does not involve the individual's own immune response to an antigen.

Innate immunity refers to the natural defenses that are present at birth and provides a general response to pathogens; it does not require prior exposure to an antigen. Examples include physical barriers like skin and mucous membranes, as well as immune cells that act quickly.

Natural immunity can sometimes be used interchangeably with active immunity, which refers to immunity developed through the immune system's response to an infection. However, in the context of this question, "specific immunity" is the more precise term to describe the active, acquired nature of immunity upon exposure to an antigen.