Which statement concerning passive immunity is least accurate?

Which statement concerning passive immunity is least accurate?

• A. It involves antibodies that have been produced in a donor animal
• B. It provides immediate but short-lived immunity
• C. It may be natural or artificial
• D. It develops after exposure to a pathogen

Answer: (D)

Passive immunity is the transfer of antibodies from one individual to another, providing immediate protection but without the recipient actively producing antibodies. Because the antibodies come from a donor, there’s no activation of the recipient’s own immune system to create antibodies or memory. That’s why the idea that immunity “develops after exposure to a pathogen” isn’t accurate for this type of immunity—it describes active immunity, where the host’s own immune system responds to an exposure and builds lasting defense. The other statements fit passive immunity: it involves antibodies from a donor, it gives quick but short-lived protection, and it can be natural (like maternal antibodies) or artificial (such as immune serum or immunoglobulins).

Passive immunity is the transfer of antibodies from one individual to another, providing immediate protection but without the recipient actively producing antibodies. Because the antibodies come from a donor, there’s no activation of the recipient’s own immune system to create antibodies or memory. That’s why the idea that immunity “develops after exposure to a pathogen” isn’t accurate for this type of immunity—it describes active immunity, where the host’s own immune system responds to an exposure and builds lasting defense. The other statements fit passive immunity: it involves antibodies from a donor, it gives quick but short-lived protection, and it can be natural (like maternal antibodies) or artificial (such as immune serum or immunoglobulins).